MXPA05011574A - Single-walled carbon nanotube-ceramic composites and methods of use. - Google Patents

Abstract

Composites of single-walled carbon nanotubes (SWNTs) and a ceramic support (e.g., silica) comprising a small amount of catalytic metal, e.g., cobalt and molybdenum, are described. The particle comprising the metal and ceramic support is used as the catalyst for the production of the single-walled carbon nanotubes. The nanotube-ceramic composite thus produced can be used "as prepared" without further purification providing significant cost advantages. The nanotube-ceramic composite has also been shown to have improved properties versus those of purified carbon nanotubes in certain applications such as field emission devices. Use of precipitated and fumed silicas has resulted in nanotube-ceramic composites which may synergistically improve the properties of both the ceramic (e.g., silica) and the single-walled carbon nanotubes. Addition of these composites to polymers may improve their properties. These properties include thermal conductivity, thermal stability (tolerance to degradation), electrical conductivity, modification of crystallization kinetics, strength, elasticity modulus, fracture toughness, and other mechanical properties. Other nanotube-ceramic composites may be produced based on AL2O3, MgO and ZrO2, for example, which are suitable for a large variety of applications.

Description

PRODUCTS COMPOSED OF INDIVIDUAL WALL CARBON NANOTUBES AND CERAMIC SUPPORT AND METHODS OF USE FIELD OF THE INVENTION This invention relates to the field of carbon nanotubes, and more particularly, but not by way of limitation, to composite products and products comprising individual wall carbon nanotubes. BACKGROUND OF THE INVENTION Carbon nanotubes (also referred to as carbon fibrils) are seamless tubes of graphite sheets with full fullerene caps that were first described as concentric multi-layer tubes or multi-walled carbon nanotubes, and so Subsequent, as single-walled carbon nanotubes in the presence of transition metal catalysts. Carbon nanotubes have shown promising applications that include nanoscale electronic devices, high strength materials, electron field emission, microscopic points with scanning probes, and gas storage. In general, single-walled carbon nanotubes are preferred over multi-walled carbon nanotubes for use in these applications because they have fewer defects and therefore are more REF: 167941 strong and more conductors than carbon nanotubes of multiple walls of similar diameter. Defects are less likely to occur in single-walled carbon nanotubes than in multi-walled carbon nanotubes because multi-walled carbon nanotubes can survive occasional defects by forming bridges between unsaturated carbon valencies, while the individual wall carbon nanotubes do not have neighboring walls to compensate for the defects. Single walled carbon nanotubes exhibit exceptional chemical and physical properties that have opened up a vast number of potential applications. However, the availability of these new individual wall carbon nanotubes in quantities and forms necessary for practical technology is still problematic. Large-scale processes for the production of high-quality individual wall carbon nanotubes are still necessary, and adequate forms of wall-individual carbon nanotubes are still needed for application to various technologies. It is to satisfy these needs that the present invention is directed. Brief Description of the Figures Figure 1 shows a schematic figure of several reactors that can be used to produce the products of the present invention.

Figure 2 is a graph showing the concentration of C02 downstream of reactor B2 as a function of the reaction time for two Co: Mo (1: 3) / silica catalysts (2% metal loading) with two different compositions of silica (silica gel 60 and Hi-SilMR-210). The reaction ran at 850 ° C with a space velocity of 67,000 h "1. Figure 3 is a scanning electron micrograph of a composite product of nanotubes and ceramic support showing the bundles of SWNT that remain interspersed between the silica particles. Figure 4 is a graph of I versus V showing curves for composite products prepared at different temperatures and different concentrations of La Figure 5 is a TE image of prepared MCM-41 support material Figure 6 is a spectrum of XRD of MCM-41 prepared as Figure 5. Figure 7 is a graph of I versus V showing curves for nanotube composite products and ceramic support prepared using various silica supports Figure '8 is a plot of. V that shows curves for products composed of nanotubes and ceramic support Aerosil 380 synthesized at 750 ° C and 850 ° C. Figure 9 is a graph of I versus V showing curves for two Products composed of nanotubes and ceramic support with different metal loads (2% and 6%). Figure 10 is a graph of I versus V that shows curves for composite products and SWNT after different purification treatments. Detailed Description of the Invention The present invention contemplates products composed of single wall carbon nanotubes (SWNT) and a ceramic support (e.g., silica) comprising a small amount of catalytic metal, for example, cobalt and molybdenum. The particle comprising the metal and the support material is used as the catalyst for the production of the individual wall carbon nanotubes. The composite product of nanotubes and ceramic support produced in this way can be used "as prepared" without further purification providing significant cost advantages. The composite product of nanotubes and ceramic support has also been shown to have improved properties over those of purified carbon nanotubes in certain applications such as field emission. Additionally, with the adjustment of the structure of the ceramic component, for example, by using a silica support without microporosity, such as precipitated and smoked silicas, a significant increase in the quality of the produced SWNTs can result. Other products composed of nanotubes and ceramic support can be produced based on support materials comprising A1203, alumina stabilized with La, gO and Zr02, for example, which are suitable for a wide variety of applications. When incorporated into the polymer matrices, these products composed of nanotubes and ceramic support can share improved polymer properties. These properties include thermal conductivity, thermal stability (tolerance to degradation), electrical conductivity, modification of crystallization kinetics, strength, modulus of elasticity, fracture hardness and other mechanical properties. These and other features and properties of the present invention are described in detail further below. The catalysts that provide the ceramic component of the nanotube and ceramic support composite product of the present invention are prepared in one embodiment by impregnating the support component (eg, silica) with different metal solutions of specific concentrations. For example, Co: Mo / SiO2 catalysts are prepared by impregnating various silica supports with aqueous solutions of cobalt nitrate and ammonium heptamolybdate to obtain the metal catalysts of the chosen compositions (see, U.S. Patent No. 6,333,016, the entirety of which is hereby expressly incorporated by reference herein). The liquid / solid relationship is maintained at incipient conditions-without moisture, which is different for each support. The total metal filler is preferably 0.1% -20% by weight. After impregnation, the catalysts are first dried preferably in air at room temperature, then in an oven at 120 ° C, and finally calcined in fluid air at 500 ° C. SWNT can be produced in these catalysts in different reactors known in the art such as fixed bed reactors, moving bed rectors, or fluidized bed reactors. The fluidized bed reactor can be operated in a batch mode as well as in a continuous mode, by way of example. The present work has used four reactors at laboratory scale to study and optimize the reaction conditions for the Co: Mo / Si02 series (Figure 1). The first reactor (A) consisted of a horizontal quartz tube 1 inch in diameter, in which a ceramic pot was placed with 0.5 g of calcined catalyst. This is a typical reactor configuration commonly found in the literature about the synthesis of carbon nanotubes. The second and third reactors (Bl and B2) are typical reactors with a fixed quartz bed of 1/8 and 1/2 inch in diameter, respectively. The reactor Bl is loaded with 0.05 g of catalyst and is considered a differential reactor when operating with a space velocity of 400,000 h. "The B2 reactor contained 0.5 g of catalyst and was run with a space velocity of 67,000? , the fourth reactor (C) is a fluidized bed reactor, in all cases, the catalyst was pre-reduced (for example, by exposure to H2 at 500 ° C) before the catalyst exposed to the reaction conditions. Prior to exposure to a carbon containing gas (eg, CO), the catalyst is heated in He up to the reaction temperature (700 ° C-1050 ° C). Subsequently, a gas containing carbon or gasified liquid is introduced. After a given reaction period that ranged from 1 to 600 minutes, the reactor was purged with He and cooled to room temperature.

For a continuous or semi-continuous system, the pretreatment of the catalyst can be done in a reactor prepared, for example, by pretreatment of much larger amounts of catalyst whereby the catalyst can be stored for later use in the SWNT production unit. With this new methodology, a fluidized bed reactor that operates continuously at the reaction temperature can be maintained, thus eliminating the preliminary steps of heating and cooling in the reaction process. By varying the reaction conditions, the catalyst selectively produces SWNT by the disproportionation of CO (decomposition at C and C02) in a preferred temperature range of 700-950 ° C (see United States patent application Serial number. 10 / 118,834, which is hereby expressly incorporated herein by reference in its entirety). A synergism between Co and Mo is critical for the performance of this catalyst [4]. Separately, these metals are not effective; neither are inactive (Mo alone) or non-selective (Co alone). The catalyst is only effective when both metals are simultaneously present in the silica support with an intimate Co-Mo interaction. The basis for the selectivity of the catalyst has been studied. Without being desired to be restricted by theory, it is believed that the selectivity towards SWNT production depends strongly on the stabilization of the C02 + species by Mo oxide species as explained below. It was found that the interaction side of Co-Mo is a function of the Co: Mo ratio in the catalyst and has different forms during the different stages of catalyst life [4]. In the calcined state, Mo is in the form of a well dispersed Mo6 + oxide. The state of Co depends strongly on the relationship of Co: Mo. At low ratios of Co: Mo, it interacts with Mo in a molybdate structure of surface Co. "At high Cp: Mo ratios, it forms a non-interacting C03O phase During the subsequent treatment of hydrogen reduction, the phase of Co of non-interaction is reduced to metallic Co, while the Co molybdate species remains as well dispersed Co2 + ions.This Co-Mo interaction inhibits Co sintering which typically occurs at the other temperatures required for the formation of carbon nanotubes When large Co particles are present, less desirable forms of carbon are produced (mainly graphite nanofibers) In contrast, when the Co agglomerates are too small so that they are only composed of a few atoms, they are produced only ST [2, 4]. When the metal atoms begin to agglomerate in the presence of gaseous CO, there is a nucleation period during which there is no nanot growth This nucleation includes the interruption of Co atoms from their interaction with Mo oxide when the latter becomes carbxadic. This interruption is followed by surface migration that results in agglomeration in the mobile agglomerates that continue to grow under the bombardment of CO molecules. Some of these molecules break down and begin to settle (nucleate) until a favorable configuration (embryo) is reached, which activates the formation of the nanotube. When this embryo is formed, the subsequent incorporation of carbon and the formation of SWNT will proceed at a rapid rate, perhaps only controlled by mass transfer. As a result, it can be concluded that the growth of each tube is limited by nucleation, and after the nucleation is completed, it is controlled by the mass transfer. For this reason, it has been observed that the decomposition of carbon in a catalyst only continues for hours, although the growth of an individual tube only takes milliseconds. The diameter of the tube is determined by the size of the embryo, therefore control of the nanotube diameter is possible by controlling the size of the metal cluster under the reaction conditions. Improvement of SWNT selectivity when using non-microporous silica as support material In systematic studies of SWNT grown under different reaction conditions, it has been shown that mass transfer limitations are important in determining the quality and performance of SWNTs. The external limitations of mass transfer can be minimized by adjusting the reaction conditions and by modifying the reactor configuration. On the other hand, in order to minimize internal diffusion problems, the pore structure and the particle size parameters of the catalyst can be adjusted. In general, small particles with larger pore sizes, or small non-porous particles can be used to reduce the internal limitations of mass transfers. However, the size of the particles can not be made much smaller without modifying the design of the reactor. Due to the high spatial velocity needed to keep the CO conversion and the high surface velocity required to minimize the external limitation of mass transfer to a minimum, excessive reduction of the catalyst particle size will excessively increase the pressure drop in a fixed bed reaction system. For this reason, a fluidized bed reaction system is a preferred alternative. In this reactor, much finer particles than one can be used in a fixed bed reactor. In some cases, particles as fine as powder can be used. In these cases, agglomeration and stickiness to the walls and between the particles can be avoided by well-established techniques such as agitation and vibration, which break the inter-particle bonds and improve the flowability. Preferably, the particle size of the powders to be used falls under the category A category of the Geldart classification. Another method that can be used to minimize the diffusion limitations that may arise during the growth of carbon nanotubes is the in situ fragmentation of the catalyst particles that expose a larger surface area to the gas phase as the reaction proceeds. . This is a typical method used in polymerization processes to improve and modify reaction kinetics [25]. The in situ fragmentation of the catalyst is obtained using a special support that may or may not require the use of special binders. This type of catalysts can be used in two ways. For example, as the nanotubes grow, the particles break up exposing new surface, and therefore, increasing the total yield of carbon obtained with this catalyst. Alternatively, a used binder is disintegrated in the support under the reaction conditions and a fine powder is generated in the reactor. Again, the use of a fine powder can increase the final carbon yield. It has been found that the microporosity of the silica support is responsible in part for the production of undesirable forms of carbon in the resulting catalyst product. The limitations of mass transfer within these micropores together with a physical impediment to the growth of the SWNT within the pores, may be responsible for the reduction of the quality of the nanotubes. This hypothesis was verified by studying the influence of the maximum temperature reached during the preheating step of the catalyst. The reactions were run at the same temperature (750 ° C) for 2 hours using a Co: Mo catalyst (1: 3) / silica gel 60 (2% metal loading). In one case, the usual procedure was used and preheated to the catalyst at 750 ° C in He. In the second case, the catalyst was first preheated to 950 ° C (thereby decreasing the microporosity) and then cooled to 750 ° C. This last pretreatment resulted in a much better product with a quality parameter c of 0.83 in so much that the first case c was just from? .62 (quality parameter c increases as the amount of amorphous carbon in the product decreases). However, they were not observed differences in the distribution of diameters of the SWNT produced and the carbon yield. The structure of the silicas is committed to a temperature as high as 950 ° C and therefore the micropores of the support tend to collapse. The average pre-treatment pore diameter of silica gel 60 is 6 nm. The individual wall nanotubes are not able to grow in pores that are much smaller than that and therefore these pores will lead to the formation of amorphous carbon. When smaller pores collapse due to preheating to 950 ° C, the production of amorphous carbon decreases and the quality of the material increases. In order to verify which hypothesis and to improve the performance of the catalyst, a different silica support with a different pore structure was studied. The new Si02 used was a precipitated silica "Hi-SilMR-210" (commercially available from PPG) that lacks microporosity. A catalyst comprising Co: Mo (1: 3) (2% metal loading) was prepared with the Hi-SilMR-210 silica and three experiments running the Boudouard reaction were carried out for 2 hours at 750 ° C, 850 ° C and 950 ° C using the same procedure as described above. The fourth reaction was also run at 750 ° C but catalyst was used which has been pre-treated with heating at 950 ° C. The results obtained for quality parameter c and carbon yield are summarized in Table 1 and were somewhat different from the results obtained for silica gel 60. No significant increase was seen in either c or carbon yield when the pre-heating and reaction temperature were 750 ° C or 850 ° C, while when preheating and reaction temperatures were 950 ° C there was an abrupt decrease of both parameters (to 0.80 and 2.0%, respectively). The second notable observation is that the quality of SWNT produced at 750 ° C and 850 ° C (c = 0.97) was much higher than that obtained using silica gel 60 even under the best operating conditions (c = 0.83) ( see previous analysis with reference to silica gel 60). Table 1 Yield and quality of SWNT obtained using a Co: o (1: 3) / Si02-Hi-SilMR catalyst in Reactor B2. The reaction was run for 2 hours at 5.8 atm. Performance Temperature Temperature (% Catalyst Preheat (° C) Reaction (, "° C") x 1-D / G by weight) Co: o (1: 3) / Si02- Hi-SilMK (2% load of 0.97 750 93% metal) Co: Mo (: 3) / Si02 - Hi-SilMR (2% load of 850 0.97 10.0% metal ) Co: o (1: 3) / S¡02- H¡-SilMR (2% load of 0.80 950 2.0% meta!) Co: Mo (1: 3) / S¡02- H¡-S¡lMR (2% load of 750 0.97 11.4% metal) The results of the preheating treatment were also important. The greatest increase in c reported before using silica gel 60 as the catalyst support when the catalyst was preheated to 950 ° C was not observed when silica with low microporosity (silica Hi-Sil) was used. the microporosity of silica gel 50 was responsible at least in part for the formation of amorphous carbon that decreased the selectivity to SWNT (ie, c decreased) The increase in quality parameter c when the reaction temperature of increase was related to the collapse of the micropores due to the high temperatures, a similar quality improvement observed when the catalyst was preheated to 950 ° C and the disappearance of this temperature effect when using Hi-SilMR-210 silica (with low microporosity) , strongly supports this hypothesis.

Interestingly, another difference observed with the silica Hi-SilMR-210 was that the yield of carbon obtained at a reaction temperature of 950 ° C was very low (only 2% by weight). In addition, the quality (ie, selectivity) (c = 0.8) | was: also much lower than the c obtained at 750 ° C and 850 ° C. These observations indicate a higher deactivation rate of the catalyst due to sintering. The smaller surface area of this product probably makes the catalyst more exposed to the sintering effect.

It is important to note that when the reaction was run at 750 ° C and 850 ° C for 2 hours, the carbon yield was slightly higher than when silica gel 60 was used. However, similar yields have been obtained with silica Hi-Sil ™ -210 for longer reaction times, showing that in reality the total reaction rates are different in both cases. Furthermore, when the C02 produced was followed by in-line mass spectroscopy (see Figure 2), it was observed that the reaction rate using Hi-SilMR-210 was at least twice as fast during the first 30 minutes of reaction as when the used silica gel 60. Subsequently, the production of C02 was sharply encouraged and became lower than for the case with the silica gel 60 catalyst. This observation indicates that the primary period of SWNT production is during the first 30 minutes of reaction. These observations provide strong evidence that internal diffusion is limiting the total reaction rate for SWNT production. Since, as mentioned below, the growth of the SWNT by themselves occurs in milliseconds, the nucleation step of the nanotubes is one that is limited by internal diffusion. Among the different phenomena that comprise the nucleation step, one that can be most likely affected is the release of the cobalt agglomerates. The Katura graphs and the Raman spectra were used to study the relationship between the diameter distribution and the reaction temperature for the production of individual wall carbon nanotubes. The Raman spectra were obtained using 633 nm and 514 nm lasers. Reactions ran for two hours in reactor B2 using Co: o (1: 3) / silica Hi-Sil "with 2% metal loading, the reaction was run at 5.8 atmospheres and at 750 ° C, 850 | C and 950 C. When silica gel 60 was used as a support as the reaction temperature increases, the SWNT produced have larger diameters and the distribution of the diameters becomes wider, for example, the average diameter for the SWNT produced. at the reaction temperature of 750 ° C it is approximately 0.9 nm, while the SWNT produced at reaction temperatures of 850 ° C and 950 ° C have diameters of about 1.1 nm and about 1.4 nm, respectively. Finally, it was observed that similar results are obtained when other non-porous silicas are used as catalyst support, for example, smoked silicas Aerosil ™ 380 and Aerosil I 4 R 90 (commercially available from Degussa Corp.), and Cab-o-silm (commercially available from Cabot Corp.)). The composite products of nanotubes and ceramic support described herein can be formed of support materials comprising nanoparticles of fumed silica (for example, 10-20 nm in diameter), precipitated silicas, silicas including silica gel, alumina (A1203). ), aluminas stabilized with La, MgO (magnesium oxide), mesoporous silicas materials including SBA-15 and Molecular Crystalline Materials (including MCM-41), zeolites (including Y, beta, KL and mordenite), and Zr02 (dioxide) of zirconium). The catalysts in one embodiment comprise cobalt and molybdenum (or other catalytic metals) and preferably comprise up to 20% by weight of the ceramic catalyst particle. · The ceramic catalyst may further comprise chlorine, for example, or other metals including Fe, Ni or W, or others as listed in U.S. Patent Nos. 6,333,016, or 6,413,487 or U.S. Patent Application Number series 60 / 529,665, each of which is hereby expressly incorporated herein in its entirety. Each product composed of nanotubes and ceramic support preferably comprises up to 50% by weight of carbon, for example, from 1 to 10% of the total weight of the composite product. Preferably, at least 50% of the SWNT have outside diameters of 0.7 nm to 1.0 nm, more preferably at least 70%, and even more preferably at least 90%. In another embodiment at least 50% of the SWNT have outside diameters of 1.0 nm to 1.2 nm, more preferably at least 70%, more preferably at least 90%. In yet a different embodiment, at least 50% of the SWNT have outside diameters of 1.2 nm to 1.8 nra, more preferably at least 70%, and more preferably at least 90%. The support materials in which the catalytic metals are placed to form the metal catalytic particles are not carbon nanotubes. Carbon nanotubes are produced only after the metal catalytic particles are exposed to the reaction conditions. Utility The catalyst-carbon nanotube support compositions produced herein can be used, for example as, electron field emitters, polymer fillers for modifying mechanical and electrical properties of polymers, coating fillers for modify mechanical and electrical properties of coatings, fillers for ceramic materials, and / or fuel cell electrode components. These are of course only examples of how the compositions of the invention can be used and the use is not limited thereto. The present ones used are described in further detail below. Uses in field emission screens Single wall carbon nanotubes have considerable attention attracted as field emitting materials due to their superior emission characteristics, high chemical stability, and outstanding mechanical strength. Although a great deal of effort has been made around the world for the applications of nanotubes to flourish, only a few have shown real potential. Among these, the field broadcast screens (FED) will be one of the first commercial applications. The EDFs are characterized by higher screen performances. Such as quick response time, wide viewing angles, wide operating temperatures, cathode ray tube (CRT) colors, ultra-thin characteristics, low cost and low power consumption. The EDF technology is one of the most promising approaches for direct view screens greater than 60 inches diagonal [5]. Nowadays, there are no well-developed technologies to grow in situ vertically aligned nanotubes on a large area of glass substrates at low temperatures. An alternative technology is the use of nanotubes produced separately and deposited later in the cathode by techniques such as stencil printing method. The deposition of a mixture of nanotubes and dielectric nanoparticles (DNP) leads to greatly improved emission characteristics [for example, see reference 6 and U.S. Patent Nos. 6,664,722 and 6,479,939]. This development makes a perfect combination with products composed of nanotubes and high quality ceramic support described herein. The products composed of nanotubes and ceramic support are particularly suitable for this application since Si02 is in the form of nanoparticles (dielectric) and has shown excellent results in this regard (see example I). The nanotube and ceramic support composite products produced herein are shown in one embodiment of Figure 3. The nano-sized particles of the silica support are physically separating bundles of separate nanotubes, which may be beneficial for emission applications. of field The nanotube and ceramic support composite products of the present invention have at least two advantages over the purely physical mixture of purified nanotubes and SiO2. In particular, the efficiency with which the silica particles separate bundles of nanotubes is much greater, and the cost of the composite products currently described is orders of magnitude less than the purified single-walled carbon nanotubes. Uses as fillers to modify mechanical and electrical properties of polymers Thermoplastic and thermosetting materials have been filled with particulate reinforcers such as Si02 to improve mechanical, thermal and chemical properties. When this reinforcing material is in the nanoscale size, the improvement of these properties is markedly greater. For this reason, fumed silica, which is available with a particle size of 10-20 nm, is commonly used as a reinforcement for PVC, silicones, acrylics (7-11) and vulcanized rubbers [12]. component for dental filling [13], electronic packaging [14], and thickeners for paints and coatings [15] Individual wall carbon nanotubes show unmatched electrical and mechanical properties, which make them good candidates for incorporation into polymer matrices In order to obtain high strength conductive polymers, however, in order to capitalize the properties of the carbon nanotubes, a good dispersion of the nanotubes in the polymer matrix is required, ideally this dispersion must contain individual nanotubes embedded in the polymer. However, although many scientists are working in this area, there is no technique developed so far that has been successful. n the achievement of this order of dispersion. The use of the nanotube and ceramic support compositions described herein as polymer fillers provides the advantages of both the nanometric sized silica and the S NT. In addition, the expression techniques that have been developed for the incorporation of SiO2 into different polymer matrices can still be applied to the composition of nanotubes and ceramic support, thereby increasing, at the same time, the dispersion of the SWNTs. This dispersion can be carried out either in the molten state of the polymer or in solutions of the polymer dissolved in solvents of varying reactivity. The reactive solvents can be low molecular weight thermosetting resins that are mixed with the matrix polymer and can improve processing conditions (eg, mix viscosity and processing temperature). further, the surface chemistry of Si02 can be easily changed for incorporation into a specific polymer matrix by generating graft sites, which can be used as anchor sites for polymer-oil filler adhesion improvement and / or sites to initiate in situ polymerization. Uses as catalysts for in situ polymerization A new technique that has been invented for use to maximize the dispersion of SWNT in polymer matrices is "in situ polymerization" (see United States patent application serial number 10 / 464,041, the entirety of which is incorporated herein by reference in its entirety). It has been shown that the properties of the SWNT-polymer composite products obtained by this technique are much better than those obtained only for a physical mixture of the same polymer and nanotubes [16, 17]. One method that was used to incorporate and disperse SW T in polymers was a technique called miniemulsion polymerization, a well-established method for producing polymer particles with very narrow size distributions. This process has the advantage of requiring substantially less surfactant to stabilize the hydrophobic reaction droplets within the aqueous medium than in the conventional emulsion polymerization. It also eliminates complicated kinetics of monomer transfer into micelles that takes place in conventional emulsion polymerization. Polystyrene composite products filled with SWNT (SWNT-PS) and styrene-isoprene prepared by this method showed distinctive physical characteristics such as: uniform black coloration; high solubility in toluene as well as in tetrahydrofuran (THF); and semiconductor to ohmic electrical behavior. In situ polymerization techniques can also be used to obtain good dispersions of the nanotube and ceramic support composite products currently claimed in different matrices. In addition, these ceramic nanotube and support composite products can be selectively adapted for in situ polymerization of specific polymers by adding an active agent to either the composite product or the bare catalyst before the nanotubes are produced. As an example, a product composed of S NT / SiO2 has been developed that has been impurified with chromium to make it effective in the in situ polymerization of ethylene. Polyethylene produced using Phillips Cr / Si02 catalysts represent 20% of the world's polyethylene production [18]. Since this catalyst needs to be activated under CO at high temperatures to be effective for polymerization [19], the present compounds of nanotubes and ceramic support doped with chromium can be easily activated for the polymerization of ethylene after growth of the nanotubes by disproportion of CO. In fact, during SWNT growth, the catalyst was treated under pure CO at high temperatures. The composite product of nanotubes and chromium-impregnated ceramic support comprises an effective polymerization catalyst. Uses as filling agents for ceramic materials Ceramic products are traditionally hard but are easy to break materials. Carbon nanotubes added to a ceramic material can improve its fracture resistance for the most part as well as increase the thermal and electrical conductivity of the ceramic product. These new materials can eventually replace conventional ceramic products. even metals in products without an account. For example, scientists have mixed alumina powder with individual cavity carbon nanotubes and then force the particles together in a combination of heat, pressure and impulse electrical current. The so-called spark plasma sintering, the method operates at lower temperatures than the conventional sintering technique used in previous attempts to make composite products reinforced with nanotubes. When the researchers produced a ceramic product with nanotubes as 5.7% of their material, the fracture hardness of the product was increased to more than twice that of a ceramic product of pure alumina. With carbon nanotubes at 10% by volume. The hardness of the ceramic product almost tripled. Due to the high price of single walled carbon nanotubes, it has been thought that previous uses of ceramic products made with these materials will probably be applications in which cost is a secondary issue, such as space vehicles and medical devices. However, the composite products of nanotubes and ceramic support described herein can be easily used to reinforce these ceramic products and additionally because of their low cost, they can make possible their use in a wide variety of applications. Uses in fuel cell electrodes The current drive to reduce the use of solid fuels due to its environmental and geopolitical impact has given fuel cells with an extraordinary thrust as attractive alternatives to combustion engines. The basic parts of a fuel cell are an ion-conducting electrolyte, a cathode, and an anode. A fuel such as hydrogen (or methanol) is put in the anode compartment where it releases electrons and forms protons, which diffuse into the cathode compartment, where they react with oxygen and consume the electrons. The electrolyte acts as a barrier for the diffusion of gas, but allows the transport of ions. Among the different types of fuel cells, the electrolyte-polymer membrane (PEM) fuel cells are generally preferred for most portable systems. They operate by transporting hydronium ions through hydrated regions of a sulphonated polymer. Due to the high conductivity of the membranes they can operate at low temperatures (<100 ° C). In addition, recent progress has allowed the use of proton conductive membranes such as Nafion (an ionomer) + silica + PW (a heteropolyacid based on phosphorous tungsten), which can operate "water-free" and at low temperatures. In parallel with the development of electrolyte membranes, great attention has been paid worldwide to the development of improved electrodes to improve reaction kinetics, decrease Pt loads and increase tolerance to CO doping. CO doping of the anode is a serious problem in PEM fuel cells. Some promising results have been obtained by allowing Pt with u, Mo, Sn, or WOx.

Several substrates have been investigated to maximize the dispersion of Pt (an electrocatalyst) and the effectiveness of the electrodes. For example, Bessel et al [20] investigated graphite nanofibers as support for fuel cell electrodes in platinum particles. They compared several types of graphite nanofibers with Vulcan carbon (XC-72). Catalysts were found to consist of 5% by weight of the platinum supported on graphite nanofibers as exhibiting activities comparable to those exhibited by approximately 25% by weight of Vulcan carbon platinum. Additionally, it was observed that metal particles supported in graphite nanofibers are significantly monkeys susceptible to CO doping that traditional catalysts. This improvement in performance was attributed to specific crystallographic orientations that Pt will adopt when dispersed in graphite nanofibers. Similarly, Rajesha et al. [21] has found that a combination of Py and W supported on multi-walled carbon nanotubes results in much more efficient electrodes for methanol fuel cells than those supported on the Vulcan carbon, which was attributed to a much greater dispersion of the metal of Pt. All these results indicate that the present single wall carbon nanotubes of nanotube composites and ceramic support product described herein (or the SWNT alone), with a much larger surface area, and a more perfect structure than the nanotubes Carbon multi-walled, or graphite nanofibers should be even more efficient. Also the higher electrical conductivity of the SWNT compared to other forms of carbon will be a favorable feature in the final electrode. Uses in solar cells Researchers at the Engineering Department of the University of Cambridge [22] have developed photovoltaic devices that, when contaminated with individual wall carbon nanotubes, perform better than non-contaminated photovoltaic devices. The nanotube diodes were made by depositing organic films containing SWNT on glass substrates coated with tin-indium oxide (ITO). The aluminum electrodes were then thermally evaporated under a vacuum to form a sandwich configuration. The interaction of the carbon nanotubes with the poly (3-octylthiophene) polymer (P30T) allows excitations generated by light in the polymer to disassociate in their separate chains and travel more easily.

The principle of operation of this device is that the interaction of the carbon nanotubes with the polymer allows the separation of charge of the photogenerated exitones in the polymer and efficient transport of electrons to the electrode through the nanotubes. The electrodes travel through the length of the nanotube and then jump or pass the tunnel to the next nanotube. This results in an increase in the mobility of the electrons and balances the transport of the charge carrier to the electrodes. In addition, the researchers found that the conductivity of the composite product is increased by a factor of 10, indicating percolation paths within the material. This contamination of the P30T polymer diodes with SWNT also improves the photovoltaic performance of the device, increasing the photocurrent by more than two orders of magnitude and doubling the open circuit voltage. The products composed of nanotubes and ceramic support have now described can be very useful for application since it requires a more controlled propagation of film and the impurification of the polymer for further improvements in the performance of these devices. In particular, the currently described nanotube and ceramic support composite products can assist in achieving the required dispersion of SWNTs in the polymer matrix used in this type of device. Additionally, the cost advantage of the present compositions makes use in economically favorable solar cells. Example "Work was carried out to determine the distribution of nanotube diameters and the amount that optimized the performance of the nanotube composite products and ceramic support in the field emission devices." The SWNT obtained at higher temperatures show more distribution wide diameter diameter centered in larger diameters than smaller sized bunches [2] .A similar diameter increase is observed when H2 is added in small concentrations to the carbon source fed to the reactor. is too high, carbon nanofibers start to form and the process loses selectivity towards SW T. For example, with pure CO, small diameter SWNTs (OD of 0.8 nm) are produced; with 3% H2 in CO the diameter increases (OD of 1.3 nm); with 10% en in multi-walled nanotubes mainly CO (OD of 19 nm) are produced. In parallel, the field emission characteristics of this series of samples were studied to determine the effect of the SWNT diameter distribution and the SWNT material quality. The I versus V curves for the corresponding nanotube and ceramic support products of the three samples are shown in Figure 4. For better performance of a field emission device, it is obvious that higher current densities are desired at a smaller field electric. With this concept in mind, it is clear that the composite product with the best performance can be obtained at 850 ° C and 3% ¾. The sample produced at 850 ° C without H2 followed this performance followed by the sample produced at 750 ° C. In all cases, the samples showed good stability, signifying little deterioration in the sample after reaching a current density of approximately 5 mA / cm2. This was observed by the low hysteresis of the I versus V curves. The influence of the dielectric structure on the field emission characteristics of the composite products of nanotubes and ceramic support was also studied. For this purpose, a series of different composite products are prepared using different silica supports for the catalyst particle. The silicas include silica gel 60 with an average pore diameter of 60 A, a silica HI-SilMR-210 with a microporosity and a surface area of 250 m2 / g, and two different aerosols (Aerosil "11 90 and Aerosil" 5 , 380) with specific surface areas of 90 and 380 m2 / g and an average particle size of 20 and 7 nm, respectively. A series of MCM-41 was also specially synthesized to try to improve field emission. Due to the highly ordered pore structure but the lower selectivity towards SVJNT during the reaction process that this material showed, the composite products provided poorer field emission performance. The silicas of MCM-41 were prepared by mixing 100 g of CTAOH with 50 g of tetramethylammonium silicate and stirring for 30 minutes. Then 12.5 g of Hi-Sil-x was added to the solution, stirred for five minutes, and poured into an autoclave. The autoclave was placed in an oven at 150 | C for 48 hours. In the removal, the autoclave was allowed to cool to room temperature. The solid was vacuum filtered with a Büchner funnel, washed with nanopure water, and dried under ambient conditions. The precipitated solid was calcined in air upon heating from room temperature to 540 ° C for a period of 24 hours then it was soaked for two hours. The calcined samples were designated MCM-41-210, MCM-41-233, and MCM-41-915 indicating the different Hi-Sil silicas "5 used to initiate." Figure 5 shows a TEM image of the MCMs synthesized. The image shows regular hexagonal array of uniform channels, which is typical for MCM-41, the average pore diameter in all samples is approximately 40 A. MCM samples were also characterized using X-ray Diffraction Spectra (XRD). The XD patterns (Figure 6) indicate that the samples exhibited hexagonal structures with a high degree of structural ordering, since all the spectra characterized three of the interplanar spacing (hkl) associated with hexagonal grid structure. The spectra are narrow (100) and well separated peaks (110) and reflections (200). The cylindrical unit cell parameter (a0) is equivalent to the interplanetary spacing of di00 / and the parameter (a0) hexagonal unit cell is equivalent to the interplanetary spacing of d100 (2 / V3). From the interplanar spacing, the pore diameter of the samples was determined from about 45 Á, which is in good agreement with the TEM data. For the study of the structure of the support, the same catalyst Co: Mo was prepared using the different supports and the products composed of nanotubes and ceramic support were prepared under reaction conditions at a temperature of 850 ° C. In this case, no hydrogen was included in the feed. The curves I versus V for these samples are shown in Figure 7. In this case, the samples with the best field emission performance were those with the Aerosil ™ silicas, which are smoked silicas with an average particle size in the range of the nanoscale. The sample Aerosil "11 90, which shows a slightly better performance than the Aerosil01 380, has an average particle diameter of 20 nm, while the Aerosil" 11 380 has an average particle size of 7 nm. The small difference in field emission characteristics of these samples seems to indicate that the average particle size of fumed silica always in the range of 7-20 nm is much less important than the overall support structure. The sample made with the silica Hi-SilMR-210 needed an electric field of 1.6 V / μt ?? more (4.02 V / μp? versus 2.41 V / μt?) than the Aerosil sample "380 to achieve the same current density (4.76 mA / cm2) .In this case, the structure of this silica is completely different since Hi -Silm-210 is a precipitated silica with a specific surface area of 150 m2 / g.An important feature of the silica Hi-Sil1 ^ -210 is its absence of microporosity.Further, silica gel 60 is highly microporous. The composite product of nanotubes and ceramic support prepared using this silica, has poor field emission performance and has not achieved current densities greater than 0.12 mA / cm 2. Similarly, the prepared MCMs, which have pore diameters in the order of 40 Á showed the same poor behavior.The lower selectivity towards SWNT of these samples as observed by the parameter of low quality (1-D / G) obtained from the Raman spectra, seems to be the reason for this phenomenon.

The Aerosil composite products "showed excellent performance achieving the current density sought in a very low electric field." To verify the correspondence of the field emission with the synthesis temperature described above using the silica Hi-SilMR-210, another was prepared Aerosil composite product ", and the product composed of nanotubes and ceramic support was synthesized at 750 ° C. The comparison with what was obtained at 850 ° C is shown in Figure 8. Again, the same trend is observed (better performance with higher synthesis temperatures). The composite product produced at 850 ° C has a better performance than that produced at 750 ° C. Another aspect of the composite product Aerosil ™ synthesized at 850 ° C which is important to point out is the extremely low hysteresis observed in its I vs. V curve. No other material tested in the present has shown this performance, with almost no deterioration of the sample after achieving current densities of almost 5 mA / cm2. Finally, the effect of the carbon content in the SWNT composite product on the field emission performance of the material was studied. To achieve this, different methods of changing the carbon / silica ratio were used. The first was to increase the carbon yield during the synthesis of the SWNT of the composite product of nanotubes and ceramic support. This was achieved by increasing the metal loading in the original catalytic particle from 2% to 6%. With this, two composite products were compared, one containing 10% SWNT and the other 20% SWNT. Although previous studies showed that optimum performance was achieved by a 50% blend of SWNT / 50% dielectric material, then the curve of I versus V of these two samples (Figure 9) showed that the material with 16% SWNT behaved worse than the material with only 10% SWNT. The yield does not increase linearly with the metal content of the catalyst and therefore the efficiency of the metal decreases as shown in Table II. For example, for two samples with 2% by weight and 10% by weight of metal, metal efficiencies were 500% by weight and 200% by weight, respectively. Although even in the best case the efficiency is low and only 147 moles of carbon are produced per mole of Co which is the active spice, the efficiencies obtained using the present synthesis method are much higher than those obtained by any other method. For example, the highest efficiency reported by Ci et al., [23] using the flotation catalyst method with acetylene as the carbon source and Fe as the active catalyst was 3.25 moles of carbon per mole of Fe. similarly, the C / Fe ratio in the HipCO ™ method is 10/1 [24]. Table II also shows the quality parameter X (lD / G) obtained from the Raman spectra (laser of 514 nm) of the product obtained using the different catalysts (2% by weight, 6% by weight and 10% by weight of metal charge). Although there is a clear trend where the quality parameter decreases as the metal load increases, it is important to note that the quality of the SWNT does not differ much in this metal loading range and should not be a factor in the difference in the emission of metal. countryside.

Table II Parameter of quality 1-D / G, carbon efficiency and efficiency of Metal as a function of metal loading in a catalyst series Co: Mo (1: 3) / Si02-Hi-Sil®. The reaction ran at 750 ° C and 5.8 atmospheres Carry-out of Redemption of 1.-D / G, Efficiency, (m.carbon, mo.lco.) (% by weight) (or in peS0.) Ocarbon gmetal) 2% 0.947 10% 500% 147 6% 0.946 16% 272% 80 10% 0.940 19% 192% 56 In conclusion, the increase in metal / SWNT ratio produced a decrease in field emission performance and therefore, the preferred composite product of nanotubes and ceramic support is that with only 10% SWNT but the maximum SWNT / metal ratio . Although working with the composite product of nanotubes and ceramic support produced as shown here (without purification) has a significant cost advantage, other subsequent treatments were tested to increase the SWNT content. The subsequent treatment consisted of the removal of the metals by an acid attack with concentrated HCl and the partial removal of the silica support by basic attacks with a solution of NaOH and an acid attack with an HF solution.

The sample treated with NaOH increased the SW T concentration to 80% but resulted in a product with no field emission at all. Samples purified with HF reduced the amount of silica resulting in even more a material with only traces of silica. This material was tested in two different ways. One, in a gel form as a result of the purification process containing mainly 1% SWNT and 99% water, and a second one in dry form resulting from lyophilization of the gel. Figure 10 shows a comparison of these two new samples with the composite product of nanotubes and ceramic support, in the form of I versus V curves. Again, these purification methods did not result in any improvement in the field emission of the nanotubes. rather, they significantly reduced the performance of the material. Finally, the best field emission material has been the composite product of nanotubes and ceramic support with a SWNT content of 10%. Changes may be made in the construction and operation of the various components, elements and assemblies described herein or in the steps or sequence of steps of the methods described herein without departing from the scope of the invention as defined in the following claims. Literature Cited 1. "Method of Producing Nanotubes" D. E. Resasco, B.

Kitiyanan, J. H. Harwell, W. Alvarez. Ü.S. Patent No. 6,333,016 (2001). "Method and Apparatus for Producing Nanotubes" D. E Resasco, L. Balzano, W. Alvarez, B. Kitiyanan, US Patent 6,413,487 (2002) 2. "Characterization of single-walled carbon nanotubes (SWNT) produced by CO disproportionation on Co- or catalysts. "E. Alvarez, F. Pompeo, JE Herrera, L. Balzano, and DE Resasco, Chemistry of Materials 14 (2002) 1853-1858 3." Synergism of Co and Mo in the catalytic production of single-wall carbon nanotubes by decomposition of CO "WE Alvarez, B. Kitiyanan, A. Borgna, and DE Resasco, Carbon, 39 (2001) 547-558 4. "Relationship Between the Structure / Composition of Co-Mo Catalysts and their Ability to Produce Single- alled Carbon Nanotubes by CO Disproportionation "José E. Herrera, Leandro Balzano, Armando Borgna, alter E. Alvarez, Daniel E. Resasco, Journal of Catalysis 204 (2001) 129 5." Large screen home FEDs for advanced digital broadcasting ", F. Sato and M. Seki , Proc. of Asia Display / IDW '01, Nagoya, Japan (2001) 1153 6. "New CNT Composites for FEDs That Do Not Require Activation" D. S. Mao, R. L. Fink, G. Monty, L. Thuesen, and Z. Yaniv, Proc. 9th Int. Display Workshops / IDW'02, Hiroshima, Japan (2002) 1415 7. "Transmittance and mechanical properties of ???? - fumed silicas composites" B. Abramoff, J. Covino, J. Appl. Poly. Sci. 46 (1989) 8. "Study of the effect of the effect of fumed silica on rigid PVC properties" S. Fellahi, S. Boukobbal, F. Boudjenana, J. Vinyl. Tech. 15 (1993) 17-21 9. "Influence of fumed silica properties on the processing, curing and reinforcement properties of silicone rubber" H Cochrane, C.S. Lin, Rubber Che. Technol. 66 (1993) 48-60 10. "Rheological and mechanical properties of filled rubber: silica-silicone" M. I. Aranguren, E. Mora, C.W. Macosko, J. Saarti, Rubber Chem. Technol. 67 (1994) 820-33 11. 11 Compounding fumed silicas into polydimethylsiloxane: bound rubber and final aggregate size "M. I. Aranguren, E. Mora, C. W. Macosko, J. Saam, J." Colloid Interface Sci .. 195 (1997) 329-37 12. "Effect of polymer-filler and filler-filler interactions on dynamic properties of filled vulcanizates" M.J. Wang, Rubber Che. Technol. 71 (1998) 520-89 13. "Dental material with inorganic filler partioles coated, with polymerizable binder" H. Rentsch, W. Mackert, Sur. Pat. Appl., EP 732099 A2 19960918 (1996) 14. "Thermal conductivity, elastic modulus, and coefficient of thermal expansion of polymer composites filled with ceramic parts for electronic packaging." CP .. Wong, Bollampally, S. Raja, J. Appl. Polyrn. Sci. 74 (1999) 3396-403 15. "Role of rheological additives in protective coatings" RE Van Dorem, DN Nash, A. Smith, J. Protective Coatings Linings 6 (1989) 47-52 16. "SWNT-filled thermoplastic and elastomeric composites prepared by miniemulsion polymerization "H. Barraza, F. Pompeo, E. O'Rear, DE Resasco, Nano Letters 2 (2002) 797-802 17." Nucleation of Polypropylene Crystallization by Single-alled Carbon Nanotubes ", BP Grady, F. Pompeo, RL Shambaugh, and DE Resasco, Journal of Physical Chemistry B 106 (2002) 5852-5858 catalysts ", AB Gaspar, LC Dieguez, Applied Catalysis A: General 227 (2002) 241-254 18. A. Razavi, Chemistry 3 (2000) 615 19. "The influence of Cr precursors in the ethylene polymerization on Cr / Si02 catalysts", AB Gaspar, LC Dieguez, Applied Catalysis A: General 227 (2002) 241-254 20. "Graphite Nanofibers as an Electrode for Fuel Cell Applications ", Bessel, Carol A, Laubernds, Kate, Rodriguez, Nelly M. Baker, R. Terry K., J. Phys. Chem. B (2001), 105, 1089 ^ -5647 21." Pt-W03 supported on carbon nanotubes as possible anodes for direct methanol fuel cells ", B. Rajesha, V. Karthik, S. Karthikeyan, R. Ravindranathan Thampi, J.-M. Bonard, B. Vis anathan Fuel81 (2002) 2177-2190 22." Single -wall carbon nanotube / conjugated polymer photovoltaic devices ", Kymakis, E.; Amaratunga, GAJ, Applied Physics Letters (2002), 80 (1), 112-114 23. Ci L., Xie S., Tang D., Yan X., Li Y., Liu Z., Zou X., Zhou W., Wang G., Chem. Phys. Lett. , 349 (3,4) (2001) 191 24. Nikolaev P., Bronikowski. J., Bradley R.., Rohmund F. , Colbert D.T., Smith K.A. , Smalley R.E., Chem. Phys. Lett., 313 (1999) 91 25. Laurence, R.L., and M.G. Chiovetta, "Heat and Mass Transfer During Olefin Polymerization for the Gas Phase, "Polymer Reaction Engineering: Influence of Reaction Engineering on Polymer Properties," H. Reichert and W. Geisler, eds., Hanser, Munich (1983) It is noted that in relation to this date , the best method known by the applicant to carry out the present invention is that which is clear from the present description of the invention.

Claims (1)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A product composed of carbon nanotubes and ceramic support, characterized in that it comprises: a metallic catalytic particle, comprising: at least one of Co, Ni , Ru, Rh, Pd, Ir, Pt, at least one Group VIb metal, and a support material, combined to have a particulate form; and a carbon product deposited in the metallic catalytic particle, at least 80% of the carbon product comprising individual wall carbon nanotubes. 2. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least one metal of group VIb of the metallic catalytic particle is selected from the group consisting of Cr, Mo and. 3. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that the support material of the metallic catalytic particle is selected from the group consisting of silicas, mesoporous silicas materials (including MCM-41 and SBA-15), aluminas stabilized with La, aluminas, MgO, Zr02, magnesium oxide stabilized with aluminum, and zeolites (including Y, beta, mordenite, and KL). 4. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 90% of the carbon product is carbon nanotubes of individual wall. 5. The product composed of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 95% of the solid carbon product are individual wall carbon nanotubes. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 50% of the individual wall carbon nanotubes have outside diameters of 0.7 nm to 1.0 nm. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 70% of the individual wall carbon nanotubes have outside diameters of 0.7 .. nm to 1.0 nm. 8. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 90% of the individual wall carbon nanotubes have outer diameters of 0.7 nm to 1.0 nm. 9. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 50% of the individual wall carbon nanotubes have outside diameters of 1.0 nm to 1.2 nm. 10. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 70% of the individual wall carbon nanotubes have outside diameters of 1.0 nm to 1.2 nm. 11. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 90% of the individual wall carbon nanotubes have outside diameters of 1.0 nm to 1.2 nm. 12. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 50% of the individual wall carbon nanotubes have outside diameters of 1.2 nm to 1.8 nm. 13. The product composed of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 70% of the individual wall carbon nanotubes have outside diameters of 1.2 nm to 1.8 nm. 14. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 90% of the individual wall carbon nanotubes have outside diameters of 1.2 nm to 1.8 nm. 15. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that the support material is fumed silica. 16. A product composed of a nanotube-polymer characterized in that it comprises a polymer and the composite product of carbon nanotubes and ceramic support of claim 1. 17. A ceramic compound product material characterized in that it comprises the composite product of nanotubes and ceramic support of the claim 1 and a ceramic matrix. 18. A fuel cell electrode characterized in that it comprises the composite product of nanotubes and ceramic support of claim 1, an electrocatalyst, and an ionomer. 19. A field emission material, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 1 and a binder, and wherein the field emission material can be dispersed by adhesion on an electrode surface. 20. A field emission device, characterized in that it comprises the field emission material of claim 19. 21. A product composed of carbon nanotubes and ceramic support, characterized in that it comprises: a metallic catalytic particle comprising: Co and Mo in a a ratio of a part of Co to at least two or more parts of Mo, and a support material, and wherein the Co, Mo and the support material are combined to have a particulate form; and a solid carbon product deposited in the metallic catalytic particle, at least 80% of the carbon product comprising individual wall carbon nanotubes. 22. The composite product of nanotubes and ceramic support according to claim 21, characterized in that the support material of the metallic catalytic particle is selected from the group consisting of silicas, mesoporous silicas materials (including MCM-41 and SBA-15). ), Aluminas stabilized with La, aluminas, MgO, Zr02, magnesium oxide stabilized with aluminum and zeolites (including Y, beta, mordenite and KL). 23. The composite product of carbon nanotubes and ceramic support according to claim 21, characterized in that the catalytically metallic particle comprises from about 0.1% to about 20% by weight of Co and Mo. 2. The composite product of carbon nanotubes and ceramic support, according to claim 21, characterized in that at least 90% of the carbon product are single wall carbon nanotubes. 25. The composite product of carbon nanotubes and ceramic support according to claim 1, characterized in that at least 95% of the individual wall carbon nanotubes. 26. A product composed of nanotubes-polymer characterized in that it comprises a polymer and the composite product of carbon nanotubes and ceramic support of claim 21. 27. A ceramic composite material, characterized in that it comprises the composite product of nanotubes and ceramic support of the Claim 21 and a ceramic matrix. 28. A fuel cell electrode characterized in that it comprises the composite product of nanotubes and ceramic support of claim 21, an electrocatalyst, and an ionomer. 29. A field emission material, characterized in that it comprises a composite product of nanotubes and ceramic support of claim 21 and a binder, and wherein the material of the field emission can be dispersed by adhesion on an electrode surface. 30. A field emission device, characterized in that it comprises the material of the field emission of claim 29. 31. A product composed of nanotubes and ceramic support, characterized in that it comprises: a metallic catalytic particle, comprising: Co and Mo in a ratio of a part of Co to at least two or more parts of Mo, and a silica support material, wherein the Co, the Mo and the silica support material combine to have a particulate form; and a carbon product deposited in the metallic catalytic particle, at least 80% of the carbon product comprising individual wall carbon nanotubes. 32. The composite product of "carbon nanotubes and ceramic support according to claim 31, characterized in that the metallic catalytic particles comprise from about 0.1% to about 20% by weight of CO and Mo. The composite product of carbon nanotubes and ceramic support according to claim 31, characterized in that the support material is a smoked silica. 34. The composite product of carbon nanotubes and ceramic support according to claim 31, characterized in that at least 90% of the carbon product is single wall carbon nanotubes. 35. The composite product of carbon nanotubes and ceramic support according to claim 31, characterized in that at least 95% of the carbon product are individual wall carbon nanotubes. 36. A product composed of nanotubes-polymer characterized because. it comprises a polymer and the composite product of carbon nanotubes and ceramic support of claim 31. 37. A ceramic composite material, characterized in that it comprises a composite product of nanotubes and ceramic support of claim 31 and a ceramic matrix. 38. A fuel cell electrode characterized in that it comprises the composite product of nanotubes and ceramic support of claim 31, an electrocatalyst, and an ionomer. 39. A field emission material, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 31 and a binder, and wherein the field emission material can be dispersed by adhesion on an electrode surface. 40. A "field emission" device, characterized in that it comprises the field emission material of claim 39. 41. A product composed of carbon nanotubes and ceramic support, characterized in that it is produced by the method comprising: contacting, in a reactor cell, metal catalytic particles comprising CO and Mo deposited in a support material in a ratio of one part of Co to at least two or more parts of Mo with a gas containing carbon at a temperature sufficient to selectively produce the individual wall carbon product as at least about 80% of a carbon product deposited in the catalytic particles metallic, metallic catalytic particles and the carbon product that forms the composite product of carbon nanotubes and ceramic support. 42. The composite product of carbon nanotubes and ceramic support according to claim 41, characterized in that the metallic catalytic particles additionally comprise a metal of group VIII selected from the group consisting of Ni, Ru, Rh, Pd, Ir and Pt, and mixing thereof . 43. The composite product of carbon nanotubes and ceramic support- according to claim 41, characterized in that the metallic catalytic particles further comprise a metal of group VIb, selected from the group consisting of Cr, W and mixtures thereof. 44. The composite product of nanotubes and ceramic support according to claim 41, characterized in that the metallic catalytic particles further comprise a metal of group VIII selected from the group consisting of Ni, Ru, Pd, Ir and Pt, and mixtures thereof. the same, and a metal of Group VIb, selected from the group consisting of Cr and and mixtures thereof. 45. The composite product of carbon nanotubes and ceramic support according to claim 41, characterized in that the support material of the metallic catalytic particle is selected from the group consisting of silicas, mesoporous silicas materials (including MCM-41 and SBA-15), aluminas stabilized with La, aluminas, MgO, Zr02, magnesium oxide stabilized with aluminum, and zeolites (including Y, beta, mordenite, and KL). 46. The composite product of carbon nanotubes and ceramic support according to claim 41, characterized in that the catalytically metallic particle comprises from about 0.1% to about 20% by weight of Co and Mo. 47. The composite product of carbon nanotubes and ceramic support according to claim 41, characterized in that the carbon-containing gas is selected from the group consisting of saturated hydrocarbons, aliphatic hydrocarbons, oxygenated hydrocarbons, aromatic hydrocarbons, alcohols, carbon monoxides and mixtures thereof. 48. The composite product of carbon nanotubes and ceramic support according to claim 41, characterized in that the carbon-containing gas also comprises a diluent gas. 49. The composite product of carbon nanotubes and ceramic support according to claim 41, characterized in that the temperature sufficient to selectively produce individual wall carbon nanotubes is in the range of about 700 ° C to about 1000 ° C. 50. The composite product of carbon nanotubes and ceramic support according to claim 41, characterized in that the metallic catalytic particles are fed substantially continuously in a gas stream containing carbon. 51. The composite product of carbon nanotubes and ceramic support according to claim 41, characterized in that at least about 90% of the carbon product are individual wall carbon nanotubes. 52. The composite product of carbon nanotubes and ceramic support according to claim 41, characterized in that at least about 95% of the carbon product are single wall carbon nanotubes. 53. The composite product of carbon nanotubes and ceramic support according to claim 41, characterized in that the temperature is sufficient to selectively produce individual wall carbon nanotubes and is in the range of about 800 ° C to about 950 ° C. 54. A product of carbon nanotube composite and ceramic support according to claim 41, characterized in that the temperature is sufficient to selectively produce single walled carbon nanotubes in a range from about 700 ° C to about 850 °. C. 55. A product composed of nanotubes-polymer, characterized in that it comprises a polymer and the composite product of carbon nanotubes and ceramic support of claim 41. 56. A ceramic composite material, characterized in that it comprises a product composed of nanotubes and ceramic support of Claim 41 and a ceramic matrix. 57. A fuel cell electrode, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 41, an electrocatalyst, and an ionomer. 58. A field emission material, characterized in that it comprises a composite product of nanotubes and ceramic support of claim 41 and a binder, and wherein the material of the field emission can be dispersed by adhesion on an electrode surface. 59. A field emission device, characterized in that it comprises the field emission material of claim 58. 60. A product composed of carbon nanotubes and ceramic support, characterized in that it is produced by the method comprising-. contacting, in a reactor cell, metal catalytic particles comprising Co and Mo deposited in a support material in a ratio of one part of Co to at least two or more parts of Mo with a gas containing carbon at a temperature sufficient to selectively produce the individual wall carbon product as at least about 80% of a carbon product deposited in the metal catalytic particles, the metal catalytic particles and the carbon product that forms the composite product of carbon nanotubes and ceramic support. 61. The composite product of carbon nanotubes and ceramic support according to claim 60, characterized in that the carbon-containing gas is selected from the group consisting of saturated hydrocarbons, aliphatic hydrocarbons, oxygenated hydrocarbons, aromatic hydrocarbons, alcohols, carbon monoxides. and mixtures thereof. 62. The composite product of carbon nanotubes and ceramic support according to claim 60, characterized in that the metallic catalytic particles are fed substantially continuously in a stream of the carbon-containing gas. 63. The composite product of carbon nanotubes and ceramic support according to claim 60, characterized in that the carbon-containing gas is fed from the reactor cell having the metallic catalytic particles deposited therein. 64. A polymer-nanotube composite product characterized by a polymer comprises the carbon nanotube composite product and ceramic support of claim 60. 65. A ceramic composite material, characterized in that it comprises a composite product of nanotubes and ceramic support of the Claim 60 and a ceramic matrix. 66. A fuel cell electrode, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 60, an electrocatalyst, and an ionomer. 67. A field emission material, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 60 and a binder, and wherein the field emission material can be dispersed by adhesion on an electrode surface. 68. A field emission device, characterized in that it comprises the field emission material of claim 67. 69. A product composed of carbon nanotubes and ceramic support, characterized in that it is produced by the method comprising: contacting, in a reactor cell, metal catalytic particles comprising at least one metal of group VIII, excluding iron, and at least one metal from the group VIb placed in a support material, with a gas containing carbon at a temperature sufficient to catalytically produce a carbon product comprising mainly single-walled carbon nanotubes and wherein the carbon product is deposited on the metal catalytic particles, the metallic catalytic particles and the carbon product that form the composite product of carbon nanotubes and ceramic support. 70. The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that at least one Group VIII metal is selected from the group consisting of Co, Ni, Ru, Rh, Pd, Ir, and Pt, and mixtures thereof. 71. The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that at least one Group VIb metal is selected from the group consisting of Cr, Mo and W and mixtures thereof. 72. The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that the support material of the metallic catalytic particle is selected from the group consisting of silicas, mesoporous silicas materials (including MCM-41 and SBA-15), aluminas stabilized with La, aluminas, MgO, Zr02, magnesium oxide stabilized with aluminum, and zeolites (including Y, beta, mordenite, and KL). 73. The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that the carbon-containing gas is selected from the group consisting of saturated hydrocarbons, aliphatic hydrocarbons, oxygenated hydrocarbons, aromatic hydrocarbons, alcohols, carbon monoxides and mixtures thereof. 7 The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that the temperature sufficient to selectively produce individual wall carbon nanotubes is in the range of about 700 ° C to about 1000 ° C. 75. The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that the temperature is sufficient to selectively produce individual wall carbon nanotubes in a range from about 700 ° C to about 850 ° C . 76. The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that the temperature is sufficient to selectively produce single walled carbon nanotubes and are in a range of about 800 ° C to about 950 ° C. 77. The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that the individual wall carbon nantotubes comprise at least about 60% of the carbon nanotubes in the carbon product. 78. The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that the individual wall carbon nantotubes comprise at least about 80% of the carbon nanotubes in the carbon product. 79. The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that the metallic catalytic particles are fed in a substantially continuous manner in a stream of the carbon-containing gas. 80. The composite product of carbon nanotubes and ceramic support according to claim 69, characterized in that the carbon-containing gas is fed from the reactor cell having the metallic catalytic particles deposited therein. 81. A product composed of nanotubes-polymer, characterized in that it comprises a polymer and the product composed of carbon nanotubes and ceramic support of claim 69. 82. A ceramic composite material, characterized in that it comprises a product composed of nanotubes and ceramic support of Claim 69 and a ceramic matrix. 83. A fuel cell electrode, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 69, an electrocatalyst, and an ionomer. 84. A field emission material, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 69 and a binder, and wherein the field emission material can be dispersed by adhesion on an electrode surface. 85. A field emission device, characterized in that it comprises the field emission material of claim 84. 86. A product composed of carbon nanotubes and ceramic support, characterized in that it is produced by the method comprising: contacting, in a reactor cell, metal catalytic particles comprising at least one metal of group VIII, and at least one metal of group VIb deposited in a support material, with a gas containing carbon at a temperature sufficient to catalytically produce a carbon product comprising mainly single wall carbon nanotubes and wherein the metal catalytic particles are fed in a substantially continuous manner in a stream of the gas containing carbon, and wherein the carbon product is deposited in the metallic catalytic particles, the metallic catalytic particles and the carbon product that form the composite product of carbon nanotubes and ceramic support. 87. The composite product of carbon nanotubes and ceramic support according to claim 86, characterized in that at least one Group VIII metal is selected from the group consisting of Co, Ni, Ru, Rh, Pd, Ir, and Pt, and mixtures thereof. 88. The composite product of carbon nanotubes and ceramic support according to claim 86, characterized in that at least one Group VIb metal is selected from the group consisting of Cr, Mo and W and mixtures thereof. 89. The composite product of carbon nanotubes and ceramic support according to claim 86, characterized in that the support material of the metallic catalytic particle is selected from the group consisting of silicas, mesoporous silicas materials (including MCM-41 and SBA-15), aluminas stabilized with La, aluminas, MgO, Zr02, magnesium oxide stabilized with aluminum, and zeolites (including Y, beta, mordenite, and KL). 90. The composite product of carbon nanotubes and ceramic support according to claim 86, characterized in that the carbon-containing gas is selected from the group consisting of saturated hydrocarbons, aliphatic hydrocarbons, oxygenated hydrocarbons, aromatic hydrocarbons, alcohols, monoxides of carbon and mixtures thereof. 91. The composite product of carbon nanotubes and ceramic support according to claim 86, characterized in that the temperature sufficient to selectively produce individual wall carbon nanotubes is in the range of about 700 ° C to about 1000 ° C. 92. The composite product of carbon nanotubes and ceramic support according to claim 86, characterized in that the temperature is sufficient to selectively produce individual wall carbon nanotubes in a range from about 700 ° C to about 850 ° C . 93. The composite product of carbon nanotubes and ceramic support according to claim 86, characterized in that the temperature is sufficient to selectively produce individual wall carbon nanotubes and are in a range of about 800 ° C to about 950 ° C. 94. A composite product of carbon nanotubes and ceramic support according to claim 86, characterized in that the individual wall carbon nanotubes comprise at least about 60% of the carbon nanotubes of the carbon product. 95. A composite product of carbon nanotubes and ceramic support according to claim 86, characterized in that the individual wall carbon nanotubes comprise at least about 80% of the carbon nanotubes of the carbon product. 96. A product composed of nanotubes-polymer, characterized in that it comprises a polymer and the composite product of carbon nanotubes and ceramic support of claim 86. 97. A ceramic composite material, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 86 and a ceramic matrix. 98. A fuel cell electrode, characterized by comprising the composite product of nanotubes and ceramic support of claim 86, an electrocatalyst, and an ionomer. 99. A field emission material, characterized by comprising the composite product of nanotubes and ceramic support of claim 86 and a binder, and wherein the field emission material can be dispersed by adhesion on an electrode surface. 100. A field emission device, characterized by a field comprising the field emission material of claim 99. 101. A product composed of carbon nanotubes and ceramic support, characterized by being produced by the method comprising: contacting, in a reactor cell, metal catalytic particles comprising Co and Mo placed in a carrier material with a gas containing carbon at a temperature sufficient to catalytically produce a carbon product comprising carbon nanotubes, wherein the carbon nanotubes are mainly single wall carbon nanotubes, wherein the metal catalytic particles are fed in a substantially continuous manner into a gas stream containing carbon, and wherein the carbon product is placed in the metal catalytic particles, the metal catalytic particles and the carbon product that make up the composite product of nanotubes of carbon and ceramic support. 102. The composite product of nanotubes and ceramic support according to claim 101, characterized in that the supporting material of the metallic catalytic particles is selected from the group consisting of silicas, tnesoporous silicas materials (including MCM-41 and SBA-15). ), aluminas stabilized with La, aluminas, gO, Zr02, magnesium oxide stabilized with aluminum and zeolites (including Y, beta, mordenite and L). 103. The composite product of carbon nanotubes and ceramic support according to claim 101, characterized in that the carbon-containing gas is selected from the group consisting of saturated hydrocarbons, aliphatic hydrocarbons, oxygenated hydrocarbons, aromatic hydrocarbons, alcohols, carbon monoxides and mixtures thereof. 104. The composite product of carbon nanotubes and ceramic support according to claim 101, characterized in that the temperature sufficient to selectively produce single walled carbon nanotubes is in a range of about 700 ° C to about 850 ° C. 105. The composite product of carbon nanotubes and ceramic support according to claim 101, characterized in that the temperature sufficient to selectively produce single walled carbon nanotubes is in a range of about 800 ° C to about 9500 ° C. 106. The composite product of carbon nanotubes and ceramic support according to claim 101, characterized in that the temperature sufficient to selectively produce individual wall carbon nanotubes is in a range of about 700 ° C to about 1000 ° C. 107. The composite product of carbon nanotubes and ceramic support according to claim 101, characterized in that the individual wall carbon nanotubes comprise at least about 60% of the carbon nanotubes of the carbon product. 108. The composite product of carbon nanotubes and ceramic support according to claim 101, characterized in that the individual wall carbon nanotubes comprise at least about 80% of the carbon nanotubes of the carbon product. 109. A product composed of nanotubes-polymer, characterized in that it comprises a polymer and the composite product of carbon nanotubes and ceramic support of claim 101. 110. A ceramic composite material, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 101 and a ceramic matrix. 111. A fuel cell electrode, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 101, an electrocatalyst, and an ionomer. 112. A field emission material, characterized in that it comprises the composite product of nanotubes and ceramic support of claim 101 and a binder, and wherein the field emission material can be dispersed by adhesion on an electrode surface. 113. A field emission device, characterized in that it comprises the field emission material of claim 112. SUMMARY OF THE INVENTION Compound products are single-walled carbon nanotubes (SWNT) and a ceramic support (eg, silica) comprising a small amount of catalytic metal, for example cobalt and molybdenum. The particle comprising the metal and the ceramic support is used as the catalyst for the production of the individual wall carbon nanotubes. The composite product of nanotube and ceramic support produced in this way can be used "as prepared" without further purification which provides significant cost advantages. The composite product of nanotubes and ceramic support has also been shown to have improved properties over those of purified carbon nanotubes in certain applications such as field emission devices. The use of precipitated and smoked silicas has resulted in products composed of nanotubes and ceramic support that can synergistically improve the properties of both the ceramic support (eg, silica) and the wall carbon nanotubes. individual. The addition of these composite products to polymers can improve their properties. These properties include thermal conductivity, thermal stability (tolerance to degradation), electrical conductivity, modification of crystallization kinetics, strength, modulus of elasticity, hardness to fracture, and other mechanical properties. Other products composed of nanotubes and ceramic support can be produced based on A1203, MgO and Zr02, for example, which are suitable for a wide variety of applications.