CN111763979A

CN111763979A - Preparation method of long-life anode material

Info

Publication number: CN111763979A
Application number: CN202010593683.1A
Authority: CN
Inventors: 赵玉平
Original assignee: Individual
Current assignee: Shandong Pingyin Fengyuan Carbon Products Corp
Priority date: 2020-06-27
Filing date: 2020-06-27
Publication date: 2020-10-13
Anticipated expiration: 2040-06-27
Also published as: CN111763979B

Abstract

The invention provides a preparation method of a long-life anode material, which is characterized in that a carbon nano tube and titanium oxide composite layer is prepared through anodic oxidation, the carbon nano tube is exposed through a tartaric acid corrosion oxide film, a lead oxide active layer and a titanium oxide layer are effectively stitched by the carbon nano tube, and the long-life anode material is obtained, and the predicted industrial life of the long-life anode material is 4.1 years.

Description

Preparation method of long-life anode material

Technical Field

The invention relates to the technical field of industrial wastewater treatment by electrocatalytic oxidation, in particular to a preparation method of a long-life lead dioxide anode in an electrocatalytic oxidation process.

Technical Field

Phenol is an important basic organic chemical raw material, and with the development of industrial economy, particularly the rapid expansion and growth of varieties and yield of synthetic materials, the demand of phenol and the development of downstream products are continuously increased worldwide, and the phenol is widely applied to various industries such as pharmaceutical synthesis, paint, dye, explosive, preservative, coal gasification, oil refining, fiber, machinery, pipe materials and the like. Because of different industrial departments, product types and process conditions, the composition of the wastewater and the concentration of the phenol are greatly different, and particularly the wastewater for processing the phenolic resin contains phenol with extremely high concentration.

The phenol toxicity process is as follows: in organisms, oxygen is metabolized to generate free radicals, the free radicals interact with cellular oxygen molecules, lipids, proteins and the like to cause lipid peroxidation and damage to biological macromolecules, and meanwhile, the free radicals can destroy signal molecules for regulating cell growth, proliferation and differentiation, cause DNA damage, induce apoptosis and oncogenic mutation.

After the phenol wastewater is treated by an excellent treatment technology, the harm to the environment can be avoided, and the phenol can be recycled, and the phenol wastewater mainly comprises a physical and chemical method, a biological method and an advanced oxidation method. At present, in actual treatment, the three are often flexibly and jointly applied, so that advantage complementation and synergistic promotion can be realized, and a treatment system can be kept to work stably, wherein chemical methods mainly comprise a Fenton method, a wet catalytic oxidation method, an ultrasonic oxidation method, a photocatalytic oxidation method, an ozone oxidation method, an electrocatalytic oxidation method and the like.

The electrocatalytic oxidation (ECO) method generates an oxidizing agent such as OH or O3 by an anodic reaction, and can completely decompose organic substances. The method has the advantages of strong oxidation capacity, large treatment capacity, high treatment efficiency, wide application range, simple equipment, simple operation, safety, reliability and good application prospect. But the promotion and the industrial application of the electrocatalytic oxidation are restricted due to low current efficiency and short service life of the electrode. Currently, ECO is still in pioneering research at home and abroad, and the preparation of electrodes with high electrocatalytic activity, good conductivity, long service life, low cost and easy processing is still a common pursuit of technicians in the field.

It is generally believed that the electrocatalytic oxidation reaction includes a system in which direct oxidation and indirect catalytic oxidation occur at the anode in coexistence. In the direct oxidation path, organic pollutants are firstly adsorbed on the surface of an anode, are oxidized into aliphatic aldehyde, alcohol, ketone, acid and the like on the anode through electron transfer, and are further mineralized and degraded to obtain final products of CO2 and H2O, and the anode material successively passes through three periods of a metal electrode, a graphite electrode and a metal oxide electrode, which is also a three-electrode material system in electrochemistry. The metal oxide electrode overcomes the defects of the traditional carbon electrode, platinum electrode, lead alloy electrode and the like, and is a hot spot field concerned by electrochemical researchers at present. Typically, the electrodes are based on transition metals, including platinum group metal oxides, tin antimony oxides, lead dioxide, manganese dioxide, and the like.

Insoluble anodes used in the electrolysis industry should have at least three conditions: high conductivity, better electrocatalytic activity and good corrosion resistance. The titanium-based lead dioxide anode is a novel insoluble metal oxide anode material, and is widely applied to metallurgy, environmental protection and electrolytic preparation of various organic matters and inorganic matters due to the characteristics of high oxygen evolution potential, strong oxidation capacity, good corrosion resistance, good conductivity, large current passing and the like. Although the PbO2 titanium electrode has many advantages, the beta-PbO 2 has large internal stress, so that the coating cracks, TiO2 is generated on the substrate, the bonding force between the beta-PbO 2 and the substrate is reduced, the coating is easy to fall off, the service life of the electrode is greatly shortened, and the reliability and the economic benefit of engineering are seriously influenced. In order to solve the above problems, the present method mainly focuses on two aspects of electrode modification: (1) the service life of the electrode is improved by adding the intermediate layer to improve the comprehensive properties such as combination between the surface active layer and the substrate; (2) the stability of the electrode is improved by modifying the surface active layer by doping or the like. Wherein in the preparation of the intermediate layer, brush coating thermal decomposition, electrodeposition, and the like are available as alternatives. Organic gas volatilization exists in brush coating thermal decomposition, which can harm the self health of operators and the environment, moreover, metal oxide crystallization is not enough to influence the catalytic activity of the electrode when the pyrolysis temperature is too low, and titanium base material is over-oxidized when the temperature is too high, even the middle layer is thermally damaged to cause poor conduction. The electrodeposition method has strong controllability, but the effect of depositing the metal layer or the alpha-PbO 2 is not obvious. The titanium wire material is oxidized/nitrided in situ, the preparation process is complicated, and the defects of limited performance regulation and control and difficult control exist. The noble metal conductive intermediate layer is utilized to increase corrosion resistance and conductivity, which is helpful for improving electrode stability, but the high cost is determined to be incapable of engineering application. The pyrolytic and electric deposition of the alpha-PbO 2 multi-layer transition layer can also play a role in prolonging the service life.

In the prior art, Huainan has a standardAcademy (CN 108793339A) discloses a novel preparation method of a high catalytic activity electrode and a method for electrocatalytic degradation of o-chlorophenol by the same, wherein a Ti/TiO2NT electrode is prepared by an anodic oxidation method, Ti4+ is reduced into Ti3+ by electroreduction, the reduced Ti/TiO2NT electrode is taken as an anode, a Pt sheet is taken as a cathode, a saturated KCl electrode is taken as a reference electrode, the reduced Ti/TiO2NT electrode is taken as an anode, a stainless steel sheet is taken as a cathode, the saturated KCl electrode is taken as a reference electrode, and the electrode is placed in 2.0g/L of electroplating solution containing Graphene Nanosheets (GNS); the prepared titanium dioxide nanotube is coated with a graphene nanosheet interlayer by adopting an electrodeposition method, and the rare earth Sm is doped with PbO₂The preparation of the surface active layer adopts a direct current deposition method, and the deposition solution comprises 0.1-0.5M Pb (NO)₃)₂,0.01～0.02M Sm(NO₃)₃·6H₂O and 0.01M NaF, adjusting the pH value of the solution to 2, and setting the current density to be 50-70 mA/cm²The method comprises the following steps of (1) carrying out electrodeposition at 65 ℃ for 60-100 min, wherein the conductivity of titanium oxide subjected to anodic oxidation treatment is not high, so that graphene is added to improve the conductivity of an anode, but the anodic titanium oxide is in a porous structure, and the sheet graphene is used for improving the conductivity and blocking pore channels, (2) although an electrodeposition method is used between the graphene and the titanium oxide, the bonding force of the graphene and the titanium oxide is from adsorption and is not in any chemical bonding, and the subsequent electrodeposition of lead oxide inevitably causes the reduction of the bonding force of the lead oxide and the titanium oxide, obviously, the service life of the lead oxide and the titanium oxide can not meet the actual production requirement although the activity is improved, and (3) the lead oxide is in a β crystal form, has high stress and is easy to strip the surface of a heavy base material.

In addition, the university of inner Mongolia industry CN 109382083A in the prior art is a titanium dioxide nanotube photocatalytic material doped with carbon nanotubes and a preparation method thereof. The preparation process comprises the following steps: taking a substrate or a pure titanium sheet with a titanium film plated on the surface as an anode, and generating a titanium dioxide nanotube array on the surface of the anode in situ by using an anodic oxidation method; the electrolyte mainly comprises a compound containing fluorine ions, carbon nano tubes, an organic solvent and water, wherein the concentration of the carbon nano tubes in the electrolyte is 0.01-0.1 wt.%, preferably 0.05-0.1 wt.%; and then taking out the anode, and carrying out annealing treatment in an inert atmosphere to obtain the carbon nanotube doped titanium dioxide nanotube photocatalytic material. The invention synchronously dopes the carbon nano tube and prepares the titanium dioxide nano tube, simplifies the preparation process, and compared with a pure titanium dioxide nano tube array, the obtained photocatalytic material has the advantages of wider absorption wavelength range, higher photocatalytic efficiency, longer cycle service life and the like. The prior art provides a means for compounding carbon nanotubes with an oxide film, but suffers from the following technical problems: (1) the carbon nano tube is not pretreated, so that the binding force of the rest titanium oxide is in consideration; (2) the base material is used as a photocatalytic material, can be widely applied to multiple fields of photocatalysis, dye-sensitized batteries, gas sensors and the like, and can be used for preparing electrodes without any hint.

Based on the above, as Ti/PbO₂Electrode, its performance and method of use have been improved, and many patents have been published abroad relating to pretreatment of Ti substrates, anodization to obtain α or β PbO₂And coarsening improvement using doping elements, have been maturing, but there is still a need to improve the anode lifetime modification and severely limit the industrial applications.

Disclosure of Invention

Based on the problems in the prior art, the invention provides a preparation method of a long-life anode material, which comprises the following preparation steps:

(1) providing a titanium or titanium alloy metal substrate and pretreating said metal substrate

(2) Preparing anodic oxidation liquid containing carbon nano tubes;

(3) taking the metal base material pretreated in the step (1) as an anode, taking the anodic oxidation solution prepared in the step (2) as electrolyte, and carrying out anodic oxidation treatment on the base material to form an anodic oxidation film on the surface of the metal base material, wherein a carbon nano tube is coated in the anodic oxidation film;

(4) removing part of the anodic oxide film by chemical corrosion to expose the carbon nano tube;

(5) deionized water rinseObtaining Ti/TiO₂-CNT material

(6) Preparing lead-containing electrodeposition solution;

(7) with the Ti/TiO obtained in step (5)₂Preparing Ti/TiO by taking a CNT material as an anode and a platinum sheet as a cathode₂-CNT/β -lead oxide.

Further, the pretreatment comprises mechanical grinding, alkali washing and acid washing, wherein the grinding is that grinding and polishing are sequentially carried out by using 300-mesh sand paper and 800-mesh sand paper, then deionized water is used for washing, and the alkali washing is a mixed aqueous solution of 10-20g/L sodium carbonate, 10-20g/L trisodium phosphate, 10-20g/L sodium silicate and 1-2g/L polyoxyethylene octylphenol ether at the temperature of 40-50 DEG C^oC, the time is 10-15 min.

(a) Regarding the pretreatment: the pretreatment mainly aims at removing organic matters and other oxides such as oil stains and the like attached to the surface of the titanium plate, and simultaneously etching the titanium-based surface into an uneven fresh rough surface so as to increase the real surface area of the titanium substrate, so that the bonding force between the active coating and the substrate is enhanced, the mechanical bonding degree of the active coating and the substrate is improved, the service life of the coating is prolonged, and the polishing aims at enabling the rough surface of the metal to be flat and smooth.

Alkali washing: the titanium substrate is stained with oil stains in the processing process, and is adhered with antirust oil, cutting oil and the like, so the oil stains must be removed before the pickling process, sodium carbonate is used for replacing sodium hydroxide, the sodium carbonate is weaker than the sodium hydroxide in alkali property and has certain saponification capacity, the pH value of the solution is buffered, but the water washing performance is poorer, therefore, trisodium phosphate is added, the oil removing and buffering effect is achieved, the water washing performance is good, in addition, sodium silicate is added, the corrosion inhibition performance of the alkaline washing solution can be enhanced by the sodium silicate, and the sodium silicate can be used in a compound way with the subsequent octyl phenol polyoxyethylene ether, has certain saponification capacity and can be used as a wetting agent and a lubricating agent. When chemical degreasing is carried out, the degreasing solution should be heated, on one hand, the saponification and emulsification are enhanced by heating, on the other hand, the soap solubility is increased by increasing the temperature, but the temperature is not too high and is generally controlled to be 40-50^oC

Further, the acid washing is a composite acid washing solution of 2-3wt.% oxalic acid and 1-1.5wt.% hydrochloric acid, and the acid washing temperature is 50-60%^oC, time 30-40miAnd n, washing for multiple times by using deionized water after acid washing.

(b) Acid washing: the purpose of the acid treatment is to enhance the binding force between the substrate and the anodic oxide, thereby improving the conductivity and prolonging the service life of the electrode. The surface of the substrate etched by the acid can form an uneven pitted surface, so that the substrate has a large surface area, the current density is reduced, and the electrochemical performance of the electrode is improved. At the same time, the oxide film on the surface of the titanium substrate can be removed. Generally speaking, the surface of a titanium substrate is easily passivated by acid etching with strong oxidizing acid, the weak acid is often poor in mechanical binding force of the surface of an electrode due to insufficient corrosivity, the acid cleaning adopted by the invention is performed by using a compound cleaning solution of 2-3wt. oxalic acid and 1-1.5wt.% hydrochloric acid, and the treated titanium substrate is gray and uniform and is pitted and loses metal luster.

Further, the anodic oxidation solution in the step (2) is 4-5g/L ammonium fluoride, 300-500ml ethylene glycol, 0.15-2 wt.% of water solution of acidized carbon nano-tubes of 50-60ml, the voltage is 15-20V, the reaction time is 60-120 min, the tube diameter of the carbon nano-tubes is 50-70nm, and the length of the carbon nano-tubes is 5-8 μm.

(c) Anodic oxidation treatment: the method comprises the following steps of (1) anodizing ammonium fluoride, ethylene glycol and an acidized carbon nano tube aqueous solution, wherein the ammonium fluoride and the ethylene glycol are common anodizing liquid components, the carbon nano tube which is mainly added is known, no obvious group exists on the surface of the carbon nano tube, so that the water solubility and the organic solution solubility of the carbon nano tube are very poor, and the carbon nano tube is directly placed into electrolyte to invent obvious solid-liquid separation, so that the carbon nano tube needs to be acidized, and the acidized carbon nano tube process comprises the following steps: placing carbon nano tube in three-mouth flask, passing through 100 deg.C^oAcidifying with mixed acid, and treating with cooling water under reflux for 5H, wherein the mixed acid is 98wt.% of H with the volume ratio of 2.5:1₂SO₄And 65% -67wt.% of HNO₃The mixed acid is grafted with hydroxyl on the surface, so that the water solubility of the carbon nano tube is remarkably improved, the carbon nano tube can be perfectly compounded on the surface of the anodic titanium oxide or coated in the anodic oxide film, and the carbon nano tube has the tube diameter of 50-70nm, the length of 5-8 mu m and the concentration of 0.15-2 wt% which are preferably selected for facilitating the subsequent corrosion process.

Voltage: during the oxidation process, the voltage should be increased slowly, for example, it should be increased too fast, which may cause current concentration at the non-uniform part where the oxide film is newly formed, resulting in severe electrical breakdown at that part, causing corrosion of the metallic titanium, and the voltage is preferably 15-20V.

Temperature: the temperature is increased and the film layer is reduced, if at higher temperature, the film thickness is increased, preferably at a temperature between 25-35 deg.C, preferably 30 deg.C^oC。

Further, the chemical etching solution in the step (4) is 5-15wt.% tartaric acid, the etching time is 10-15min, and the temperature is 40-50%^oC。

(d) The corrosion process is a key content of the present invention, and the main purpose of the corrosion process is to corrode titanium oxide so as to expose carbon nanotubes coated in titanium oxide, as shown in fig. 3, in addition, the corrosion solution of the present invention is a pure tartaric acid corrosion solution, if nitric acid, hydrochloric acid, sulfuric acid, or oxalic acid, citric acid are used at the same concentration, the corrosion effect of the corrosion solution cannot effectively expose carbon nanotubes, which may be related to the property of tartaric acid, the specific principle of the corrosion solution needs to be studied, and the main purpose of corroding and exposing carbon nanotubes is to (1) effectively improve Ti/TiO₂The conductivity of CNT, the conductivity of pure titanium oxide is poor, the subsequent electrodeposition of lead oxide is not facilitated, and the conductivity of the material is effectively improved due to the addition of CNT; (2) the carbon nano tube can also generate the deposition of lead oxide in the subsequent electrodeposition process of lead oxide, and has the effect similar to sewing, when the lead oxide is stripped from the surface of titanium oxide, the carbon nano tube can play the role of sewing reinforcement, and the service life of the anode material can be effectively prolonged, and the sewing effect is good for Ti/TiO₂-CNT/β-PbO₂The long life performance of the carbon nanotube is indispensable, as shown in a schematic diagram of fig. 2, the carbon nanotube can effectively suture lead oxide and titanium oxide, as shown in a TEM of fig. 4, as shown in fig. 5 and fig. 6, the carbon nanotube is effectively connected with the lead oxide and the titanium oxide, and a lead oxide active layer is also deposited on the surface of the carbon nanotube.

Further, the lead electrodeposition solution in the step (6) is 0.45mol/L of Pb (NO)₃)₂0.01mol/L NaF and a proper amount of HNO₃Regulating p of electrolyte using tartaric acidH is 1-2.

Further, the electrodeposition parameters in the step (7) are as follows: the electrodeposition time is 1.0-1.5h, the deposition temperature is 40-50 ℃, and the electrodeposition current density is 10-15mA/cm²And the distance between the polar plates is 3-4 cm.

Further, the lead oxide obtained in the step (7) is β -PbO₂。

(e) Electro-deposition of lead oxide:

the principle is as follows: anode Pb²⁺+2H₂O→PbO₂+4H⁺+2e;2H₂O→O₂+4H⁺+4e (side reaction)

Cathode Pb²⁺+2e→Pb;2H⁺+2e→H₂

The pH of the electrodeposition bath, the temperature of the bath, the current density, the composition of the plating solution, etc., are all factors that influence the electrodeposition process.

The acidity is classified into α type and β type according to the crystal type, α -PbO2 is orthorhombic system, the size structure of crystal grains is small, the bonding force is strong, but the conductivity is poor, the stability is relatively good, and the acidity is generally obtained from alkaline lead electroplating solution, β -PbO2 is tetragonal system, the size of crystal grains is relatively large, most of the crystal grains are porous loose structures, the resistivity of the crystal grains is 96 mu & omega & cm, the pH is generally controlled to be about 10-12 when the acidity is obtained from acidic lead electroplating solution, and β -Pb0 is generally controlled to be about 10-12 when the acidity is α -Pb02₂Generally, the pH value is controlled to be about 1-2, and if the pH value is too low, an active layer on the surface of the electrode becomes brittle, the mechanical property is weakened, and the service life of the electrode is influenced: the pH value is too high, and the precipitation of cathode lead ions is serious.

Temperature: tests have shown that the higher the temperature, the lower the internal stress of the coating, the better the mechanical properties of the plated electrode, which may be related to the crystal structure of the electrodeposited layer, since the heating treatment helps to adjust the ion position inside the crystal to eliminate the internal stress. However, too high a temperature may result in a substrate of Pb0₂Oxidation occurs immediately before deposition to form an oxide film having an uneven surface resistance distribution, resulting in Pb0₂Cannot be uniformly deposited on the substrate and therefore the optimum electrodeposition temperature for different substrates will depend on the circumstances.

Current density: because the electrodeposition speed by the potentiostatic method is too slow, and the grains are coarse and the real surface area is small, the galvanostatic method is generally adopted. Most obtained at high current densities is α Pb02 and most obtained at low current densities is β Pb 02.

Referring to the XRD diffractogram of example 2 in FIG. 7, the active layer on the substrate surface is β -PbO2, and comparison of JCPDS cards shows that the positions of diffraction peaks in the diffractogram are consistent with those of the principal diffraction peaks of β -PbO2 crystals (2 θ ° =25.3, 31.9, 36.2, 49.1), and the other diffraction peak positions are also substantially consistent, i.e., the PbO prepared under the experimental conditions is₂The surface structure of the electrode is mainly β -PbO2, and no characteristic diffraction peak of titanium is found, which indicates that lead dioxide completely covers the titanium matrix, and the surface of the electrode is not exposed to the titanium matrix.

Based on the above, and as shown in fig. 1, the specific process of the present invention is as follows:

(1) providing a titanium or titanium alloy metal substrate, and pretreating the metal substrate to expose the metal substrate and obtain a rough metal surface, as shown in fig. 1 (a).

(2) Preparing anode oxidation solution containing carbon nanotubes, and anodizing to form anode oxide film on the surface of the metal substrate, wherein the anode oxide film is coated with carbon nanotubes, as shown in FIG. 1(b)

(3) Removing part of the anodic oxide film by tartaric acid chemical etching to expose the carbon nanotubes, as shown in FIG. 1 (c);

(4) the beta-lead oxide is obtained by anodic electrodeposition.

(5) Obtaining the high-life Ti/TiO₂CNT/β -lead oxide anode, as shown in FIG. 1 (d).

The beneficial technical effects are as follows:

(1) by polishing, alkaline etching and acid washing, the titanium-based surface is etched into an uneven rough surface to increase the real surface area of the titanium substrate, so that the bonding force between the active coating and the substrate is enhanced, the mechanical bonding degree is improved, and the service life of the coating is prolonged.

(2) And uniformly mixing the carbon nano tube treated by the mixed acid with the electrolyte, and obtaining a titanium oxide film and a carbon nano tube composite oxide layer in one step, wherein the titanium oxide and the carbon nano tube have strong binding force.

(3) The specific tartaric acid has good effect of corroding the anodic oxide film, and after the carbon nano tube is exposed, the Ti/TiO is added₂The CNT material is used as an anode with enhanced conductivity and can be used as a deposition site of lead oxide to effectively improve subsequent Ti/TiO₂Lifetime of CNT/β -lead oxide anodes.

(4) The proper voltage and current density are regulated to obtain the high-activity beta-lead oxide anode which has good performance of catalyzing and oxidizing industrial wastewater.

Drawings

Fig. 1 is a schematic view of a process for preparing a long-life anode material of the present invention.

FIG. 2 is a schematic view of the stitching of the anodic oxide film with the CNT on the active surface of lead oxide according to the present invention.

FIG. 3 is an SEM image of the exposure of CNTs on an anodized film etched with tartaric acid according to the present invention.

Fig. 4 is a TEM image of CNT-stitched oxide film and lead oxide of the long-lived anode material of the present invention.

Fig. 5 is an SEM image of a long-lived anode bonding interface of the present invention.

Fig. 6 is an SEM image of a long-lived anode bonding interface of the present invention.

Fig. 7 is an XRD pattern of the anode material of the present invention.

Detailed Description

Example 1

A preparation method of a long-life anode material is characterized by comprising the following preparation steps:

(1) providing a titanium or titanium alloy metal substrate, and pretreating the metal substrate, wherein the pretreatment comprises mechanical grinding, alkali washing and acid washing, the grinding is grinding and polishing by sequentially using 300-mesh and 800-mesh abrasive paper, and then washing by using deionized water, the alkali washing is a mixed aqueous solution of 10g/L sodium carbonate, 10g/L trisodium phosphate, 10g/L sodium silicate and 1g/L octylphenol polyoxyethylene ether, and the temperature is 40 DEG^oC, the time is 10min,

the acid washing is a compound acid washing solution of 2wt.% oxalic acid and 1wt.% hydrochloric acid, and the acid washing temperature is 50^oC, time 30min, pickling and washingAnd washing for multiple times by using deionized water.

(2) Preparing an anodic oxidation solution containing carbon nanotubes, wherein the anodic oxidation solution is 4g/L of ammonium fluoride, 300ml of ethylene glycol and 50ml of 0.15 wt.% of an aqueous solution of acidized carbon nanotubes, the tube diameter of each carbon nanotube is 50-70nm, the length of each carbon nanotube is 5-8 mu m, and the acidized carbon nanotube is prepared by the following steps: placing carbon nano tube in three-mouth flask, passing through 100 deg.C^oAcidifying with mixed acid, and treating with cooling water under reflux for 5H, wherein the mixed acid is 98wt.% of H with the volume ratio of 2.5:1₂SO₄And 65% -67wt.% of HNO₃And (4) mixing acid.

(3) And (2) taking the metal base material pretreated in the step (1) as an anode, taking the anodic oxidation solution prepared in the step (2) as electrolyte, and carrying out anodic oxidation treatment on the base material to form an anodic oxidation film on the surface of the metal base material, wherein the carbon nano tube is coated in the anodic oxidation film, the voltage of anodic oxidation is 15V, and the reaction time is 60 min.

(4) Removing part of the anodic oxide film by chemical corrosion to expose the carbon nano tube; the chemical etching solution is 5wt.% tartaric acid, the etching time is 10min, and the temperature is 40%^oC。

(5) Washing with deionized water to obtain Ti/TiO₂-a CNT material.

(6) Preparing a lead-containing electrodeposition solution: 0.45mol/L Pb (NO) of lead electrodeposition liquid₃)₂0.01mol/L NaF and a proper amount of HNO₃And adjusting the pH of the electrolyte to 1 by using tartaric acid.

(7) With the Ti/TiO obtained in step (5)₂Preparing Ti/TiO by taking a CNT material as an anode and a platinum sheet as a cathode₂CNT/β -lead oxide, the electrodeposition parameters being 1.0-h electrodeposition time, 40 ℃ deposition temperature and 10mA/cm electrodeposition current density²And the distance between the polar plates is 3 cm.

Example 2

(1) providing a titanium or titanium alloy metal substrate and carrying out pretreatment on the metal substrate, wherein the pretreatment comprises mechanical polishing, alkali washing and acid washing, and the pretreatment comprises the steps of mechanical polishing, alkali washing and acid washingThe grinding is to use 300-mesh and 800-mesh sand paper to grind and polish in sequence and then wash with deionized water, wherein the alkali wash is a mixed aqueous solution of 15g/L sodium carbonate, 15g/L trisodium phosphate, 15g/L sodium silicate and 1.5g/L polyoxyethylene octylphenol ether, and the temperature is 15 DEG^oC, the time is 12.5min,

the acid washing is a composite acid washing solution of 2.5 wt.% oxalic acid and 1.25wt.% hydrochloric acid, and the acid washing temperature is 55 DEG C^oC, time 35min, and washing for multiple times by using deionized water after acid washing.

(2) Preparing an anodic oxidation solution containing carbon nanotubes, wherein the anodic oxidation solution is 4.5g/L of ammonium fluoride, 400ml of ethylene glycol and 55ml of 0.175 wt.% of an aqueous solution of acidized carbon nanotubes, the tube diameter of each carbon nanotube is 50-70nm, the length of each carbon nanotube is 5-8 mu m, and the process of the acidized carbon nanotubes is as follows: placing carbon nano tube in three-mouth flask, passing through 100 deg.C^oAcidifying with mixed acid, and treating with cooling water under reflux for 5H, wherein the mixed acid is 98wt.% of H with the volume ratio of 2.5:1₂SO₄And 65% -67wt.% of HNO₃And (4) mixing acid.

(3) And (2) taking the metal base material pretreated in the step (1) as an anode, taking the anodic oxidation solution configured in the step (2) as electrolyte, and carrying out anodic oxidation treatment on the base material to form an anodic oxidation film on the surface of the metal base material, wherein the carbon nano tube is coated in the anodic oxidation film, the voltage of anodic oxidation is 17.5V, and the reaction time is 90 min.

(4) Removing part of the anodic oxide film by chemical corrosion to expose the carbon nano tube; the chemical etching solution is 10wt.% tartaric acid, the etching time is 12.5min, and the temperature is 45%^oC。

(5) Washing with deionized water to obtain Ti/TiO₂-a CNT material.

(6) Preparing a lead-containing electrodeposition solution: 0.45mol/L Pb (NO) of lead electrodeposition liquid₃)₂0.01mol/L NaF and a proper amount of HNO₃And adjusting the pH of the electrolyte to 1.5 by using tartaric acid.

(7) With the Ti/TiO obtained in step (5)₂Preparing Ti/TiO by taking a CNT material as an anode and a platinum sheet as a cathode₂CNT/β -lead oxide, electrodeposition parameters being 1.25h at 45 ℃ for an electrodeposition timeThe deposition current density is 12.5mA/cm²The distance between the polar plates is 3.5cm and is named as S-2.

Example 3

(1) providing a titanium or titanium alloy metal substrate, and pretreating the metal substrate, wherein the pretreatment comprises mechanical grinding, alkali washing and acid washing, the grinding is grinding and polishing by sequentially using 300-mesh and 800-mesh abrasive paper, and then washing by using deionized water, and the alkali washing is a mixed aqueous solution of 20g/L sodium carbonate, 20g/L trisodium phosphate, 20g/L sodium silicate and 2g/L octylphenol polyoxyethylene ether, and the temperature is 50 DEG^oC, the time is 15min,

the acid washing is a composite acid washing solution of 3wt.% oxalic acid and 1.5wt.% hydrochloric acid, and the acid washing temperature is 60^oC, the time is 40min, and deionized water is used for washing for multiple times after acid washing.

(2) Preparing an anodic oxidation solution containing carbon nanotubes, wherein the anodic oxidation solution is 5g/L of ammonium fluoride, 300-500ml of ethylene glycol and 60ml of an aqueous solution of 2wt.% of acidized carbon nanotubes, the tube diameter of the carbon nanotubes is 50-70nm, the length of the carbon nanotubes is 5-8 μm, and the acidized carbon nanotubes have the following process: placing carbon nano tube in three-mouth flask, passing through 100 deg.C^oAcidifying with mixed acid, and treating with cooling water under reflux for 5H, wherein the mixed acid is 98wt.% of H with the volume ratio of 2.5:1₂SO₄And 65% -67wt.% of HNO₃And (4) mixing acid.

(3) And (2) taking the metal base material pretreated in the step (1) as an anode, taking the anodic oxidation solution prepared in the step (2) as electrolyte, carrying out anodic oxidation treatment on the base material, forming an anodic oxidation film on the surface of the metal base material, coating carbon nano tubes in the anodic oxidation film, and carrying out anodic oxidation at a voltage of 20V for reaction for 120 min.

(4) Removing part of the anodic oxide film by chemical corrosion to expose the carbon nano tube; the chemical etching solution is 15wt.% tartaric acid, the etching time is 15min, and the temperature is 50%^oC。

(5) Washing with deionized water to obtain Ti/TiO₂-a CNT material.

(6) The configuration comprisesLead electrodeposition liquid: 0.45mol/L Pb (NO) of lead electrodeposition liquid₃)₂0.01mol/L NaF and a proper amount of HNO₃And adjusting the pH of the electrolyte to 2 by using tartaric acid.

(7) With the Ti/TiO obtained in step (5)₂Preparing Ti/TiO by taking a CNT material as an anode and a platinum sheet as a cathode₂CNT/β -lead oxide, the electrodeposition parameters being 1.5h at 50 ℃ and a current density of 15mA/cm²And the distance between the polar plates is 4 cm.

Comparative example 1

The preparation method comprises the following preparation steps:

(1) providing a titanium or titanium alloy metal substrate, and pretreating the metal substrate, wherein the pretreatment comprises mechanical grinding, alkali washing and acid washing, the grinding is grinding and polishing by sequentially using 300-mesh and 800-mesh abrasive paper, and then washing by using deionized water, the alkali washing is a mixed aqueous solution of 15g/L sodium carbonate, 15g/L trisodium phosphate, 15g/L sodium silicate and 1.5g/L octylphenol polyoxyethylene ether, and the temperature is 15 DEG^oC, the time is 12.5min,

(2) Preparing an anodic oxidation solution containing carbon nanotubes, wherein the anodic oxidation solution is 4.5g/L of ammonium fluoride, 400ml of ethylene glycol and 55ml of 0.175 wt.% of aqueous solution of the carbon nanotubes, the tube diameter of the carbon nanotubes is 50-70nm, the length of the carbon nanotubes is 5-8 mu m, and the carbon nanotubes are not subjected to any pretreatment.

(3) And (3) taking the metal base material pretreated in the step (1) as an anode, taking the anodic oxidation solution prepared in the step (2) as electrolyte, and carrying out anodic oxidation treatment on the base material, wherein the voltage of anodic oxidation is 17.5V, and the reaction time is 90 min.

(4) Removing part of the anodic oxide film by chemical etching, wherein the chemical etching solution is 10wt.% tartaric acid, the etching time is 12.5min, and the temperature is 45 DEG^oC。

(5) Washing with deionized water to obtain Ti/TiO₂-a CNT material.

(6) Is prepared with leadElectro-deposition solution: 0.45mol/L Pb (NO) of lead electrodeposition liquid₃)₂0.01mol/L NaF and a proper amount of HNO₃And adjusting the pH of the electrolyte to 1.5 by using tartaric acid.

(7) With the Ti/TiO obtained in step (5)₂Preparing Ti/TiO by taking a CNT material as an anode and a platinum sheet as a cathode₂CNT/β -lead oxide, the electrodeposition parameters being 1.25h at 45 ℃ and at a current density of 12.5mA/cm²The distance between the polar plates is 3.5cm and is named as D-1.

Comparative example 2

The preparation method comprises the following preparation steps:

(2) Preparing an anodic oxidation solution containing carbon nano tubes, wherein the anodic oxidation solution is 4.5g/L of ammonium fluoride and 400ml of ethylene glycol.

(5) Washing with deionized water to obtain Ti/TiO₂A material.

(7) With the Ti/TiO obtained in step (5)₂The material is an anode, a platinum sheet is a cathode, and Ti/TiO is prepared₂CNT/β -lead oxide, the electrodeposition parameters being 1.25h at 45 ℃ and at a current density of 12.5mA/cm²The distance between the polar plates is 3.5cm and is named as D-2.

Comparative example 3

The preparation method comprises the following preparation steps:

(4) Removing part of the anodic oxide film by chemical corrosion to expose the carbon nano tube; the chemical etching solution is 10wt.% hydrochloric acid, the etching time is 12.5min, and the temperature is 45%^oC。

(5) Washing with deionized water to obtain Ti/TiO₂-a CNT material.

(7) With the Ti/TiO obtained in step (5)₂Preparing Ti/TiO by taking a CNT material as an anode and a platinum sheet as a cathode₂CNT/β -lead oxide, the electrodeposition parameters being 1.25h at 45 ℃ and at a current density of 12.5mA/cm²The distance between the polar plates is 3.5cm and is named as D-3.

Comparative example 4

The preparation method comprises the following preparation steps:

(4) Removing part of the anodic oxide film by chemical corrosion to expose the carbon nano tube; the chemical etching solution is 10wt.% nitric acid, the etching time is 12.5min, and the temperature is 45 DEG^oC。

(5) Washing with deionized water to obtain Ti/TiO₂-a CNT material.

(7) With the Ti/TiO obtained in step (5)₂Preparing Ti/TiO by taking a CNT material as an anode and a platinum sheet as a cathode₂CNT/β -lead oxide, the electrodeposition parameters being 1.25h at 45 ℃ and at a current density of 12.5mA/cm²The distance between the polar plates is 3.5cm and is named as D-4.

Comparative example 5

The preparation method comprises the following preparation steps:

(2) Preparing an anodic oxidation solution containing carbon nanotubes, wherein the anodic oxidation solution is 4.5g/L of ammonium fluoride, 400ml of ethylene glycol and 55ml of 0.175 wt.% of an aqueous solution of acidized carbon nanotubes, the tube diameter of each carbon nanotube is 50-70nm, the length of each carbon nanotube is 5-8 mu m, and the process of the acidized carbon nanotubes is as follows: placing carbon nano tube in three-mouth flask, passing through 100 deg.C^oC, acidifying with mixed acid, and carrying out cooling water reflux treatment for 5 hours, wherein the volume of the mixed acid is98wt.% H in a 2.5:1 ratio₂SO₄And 65% -67wt.% of HNO₃And (4) mixing acid.

(4) Removing part of the anodic oxide film by chemical corrosion to expose the carbon nano tube; the chemical etching solution is 10wt.% citric acid, the etching time is 12.5min, and the temperature is 45%^oC。

(5) Washing with deionized water to obtain Ti/TiO₂-a CNT material.

(7) With the Ti/TiO obtained in step (5)₂Preparing Ti/TiO by taking a CNT material as an anode and a platinum sheet as a cathode₂CNT/β -lead oxide, the electrodeposition parameters being 1.25h at 45 ℃ and at a current density of 12.5mA/cm²The distance between the polar plates is 3.5cm and is named as D-5.

TABLE 1 sample Life and thermal shock testing

The life test conditions are as follows:

the electrodes prepared from the prepared S-2, D-1 to D5 were used as anodes, copper plates as cathodes, and the electrode spacing was 10mm, and the electrode was measured at 60 ℃ at 1.0mol/L H₂SO₄In the aqueous solution, the current density increased by 0.5A/cm per minute from zero²Until the current density is 4.0A/cm²The stable current density is kept at 4.0A/cm²The test is carried out, the initial tank voltage is about 4.5V, when the operating voltage is increased to 10V, the initial tank voltage is used as a criterion for evaluating the inactivation of the electrode,the electrolysis time at this time is the life of the electrode.

Thermal shock test conditions: the initial test temperature of the Yangping is 140 ℃, the electrode is placed in a muffle furnace for 10 minutes, taken out and rapidly placed in water at 20 ℃, and after the temperature of the muffle furnace is raised by 20 ℃, the electrode is placed in the muffle furnace and calcined until the coating is damaged and the matrix is exposed.

It is known that factors influencing the stability of the electrode are many, and the decisive effect is the bonding force of the electrode coating, if the bonding force is poor, the coating on the surface of the electrode can fall off in a working chamber, the electrodeposition effect is influenced, the service life can be shortened, the corrosion resistance can be weakened, and once corrosive liquid passes through the bonding force

Cracks generated by the poor coating enter the electrode substrate, and the electrode fails immediately due to the use process of the anode

In the whole process, high current is conducted, the current has impact on the coating due to the resistance on the surface of the electrode, and if the bonding force of the electrode coating is poor, the coating can fall off due to the high current. It is also an important experiment to examine the binding force of the intermediate layer and the surface coating. If the bonding force between the electrode intermediate layer and the surface active layer is good, the stability of the electrode is improved; if the bonding force between the electrode intermediate layer and the surface active layer is poor, the stability of the electrode is also deteriorated.

Referring to the above tables 1, S-2 and D-1, D-2, the time for breakdown voltage to occur is 373h,167h,173h, respectively, the following results can be clearly obtained: (1) if the CNT is not acidified, the CNT without hydrophilic groups on the surface is agglomerated in the anodic oxidation solution and can not be deposited on the surface of the anode at all, and finally the service lives of D-1 and D-2 are basically consistent, namely the CNT added with D-2 is the same as that without D-2; (2) the CNT is crucial to the bonding force of lead oxide and titanium oxide, the stitching effect of the CNT is remarkable, the service life of S-2 is two times longer than that of a D-3 sample without the CNT, the service life of S-2 is 373h, the industrial service life is 4.1 years in conversion, and the industrial service standard is reached.

Referring to S-2 and D-3, D-4, D-5 of Table 1, the time for breakdown voltage to occur was 373h,262h,289h,327h, respectively, the following results are evident: (1) the degree of corrosion of the corrosion process has an effect on the lifetime, as is well known in the art, Pka1= -8.00 for hydrochloric acid, Pka1= -2.00 for nitric acid, Pka1=3.15 for citric acid; tartaric acid with Pka1=3.04, too strong acidity, resulting in excessive corrosion of the oxide film, strong loss of both CNT and oxide film, too weak acidity, ineffective exposure of CNT; (2) it is rarely reported that tartaric acid is more excellent in the degree of corrosion of an oxide film than hydrochloric acid, nitric acid and citric acid.

The thermal shock test method is that the prepared electrode is put in a muffle furnace to be heated to a proper temperature, the temperature is preserved for a certain time, the electrode is taken out and put in water to be cooled, the electrode is repeatedly heated and put in cold water, and then whether the surface of the electrode falls off or not is observed. The thermal shock test method is widely applied in the experiment for detecting the bonding force of the plating layer, and the basic principle of the thermal shock test method is the deformation generated by the difference of the thermal expansion coefficients of the surface plating layer and the middle plating layer. The thermal shock test was performed using a gradient temperature ramp method. Determining a temperature, observing whether the beta-PbO 2 plating layer on the surface of the electrode is damaged or not after the experiment is carried out once, if the beta-PbO 2 plating layer on the surface of the electrode is not damaged, increasing the thermal shock temperature by a fixed value, then carrying out a second thermal shock experiment until the beta-PbO 2 plating layer on the surface of the electrode is damaged and the substrate is exposed, recording the thermal shock end point temperature, and comparing the bonding force of the plating layer according to the temperature of the thermal shock experiment when the plating layer is damaged. The thermal shock end point temperature of the inventive S-2 was 280 ℃, which, by comparison, corresponded to the electrode life.

Although the present invention has been described above by way of examples of preferred embodiments, the present invention is not limited to the specific embodiments, and can be modified as appropriate within the scope of the present invention.

Claims

1. A preparation method of a long-life anode material is characterized by comprising the following preparation steps:

(1) providing a titanium or titanium alloy metal base material, and pretreating the metal base material;

(2) preparing anodic oxidation liquid containing carbon nano tubes;

(5) washing with deionized water to obtain Ti/TiO₂-a CNT material;

(6) preparing lead-containing electrodeposition solution;

(7) with the Ti/TiO obtained in step (5)₂Preparing Ti/TiO by taking a CNT material as an anode and a platinum sheet as a cathode₂-CNT/lead oxide.

2. The method for preparing a long-life anode material as claimed in claim 1, wherein the pretreatment comprises mechanical grinding, alkali washing and acid washing, the grinding is grinding and polishing by using 300-mesh and 800-mesh sand paper in sequence, and then washing by using deionized water, the alkali washing is a mixed aqueous solution of 10-20g/L sodium carbonate, 10-20g/L trisodium phosphate, 10-20g/L sodium silicate and 1-2g/L polyoxyethylene octylphenol ether, and the temperature is 40-50 DEG^oC, the time is 10-15 min.

3. The method for preparing a long-life anode material as claimed in claim 2, wherein the acid washing is a composite acid washing solution of 2-3wt.% oxalic acid and 1-1.5wt.% hydrochloric acid, and the acid washing temperature is 50-60%^oC, the time is 30-40min, and deionized water is used for washing for multiple times after acid washing.

4. The method as claimed in claim 1, wherein the anodic oxidation solution in step (2) is 4-5g/L ammonium fluoride, 300-500ml ethylene glycol, 0.15-2 wt.% water solution of acidified carbon nanotubes 50-60ml, voltage 15-20V, reaction time 60-120 min, tube diameter 50-70nm, length 5-8 μm.

5. A long life as claimed in claim 4The preparation method of the anode material is characterized in that the carbon nano tube acidizing process comprises the following steps: placing carbon nano tube in three-mouth flask, passing through 100 deg.C^oAcidifying with mixed acid, and treating with cooling water under reflux for 5H, wherein the mixed acid is 98wt.% of H with the volume ratio of 2.5:1₂SO₄And 65% -67wt.% of HNO₃And (4) mixing acid.

6. The method for preparing a long-life anode material according to claim 1, wherein the solution for chemical etching in the step (4) is 5-15wt.% tartaric acid, the etching time is 10-15min, and the temperature is 40-50%^oC。

7. The method for preparing a long-life anode material according to claim 1, wherein the lead electrodeposition bath in the step (6) contains 0.45mol/L of Pb (NO)₃)₂0.01mol/L NaF and a proper amount of HNO₃And adjusting the pH of the electrolyte to 1-2 by using tartaric acid.

8. A method for preparing a long-life anode material according to claim 1, wherein the electrodeposition parameters in the step (7) are: the electrodeposition time is 1.0-1.5h, the deposition temperature is 40-50 ℃, and the electrodeposition current density is 10-15mA/cm²And the distance between the polar plates is 3-4 cm.

9. The method for preparing a long-life anode material according to claim 1, wherein the lead oxide obtained in the step (7) is β -PbO₂。