CN105293492B - It is a kind of to heat-treat CO using graphene-based catalyst2The method for synthesizing CO - Google Patents

Abstract

CO is heat-treated using graphene-based catalyst the invention discloses a kind of₂The method for synthesizing CO, summary of the invention includes: to prepare graphene-based catalyst, establishes thermocatalytic reduction CO₂Synthesize the experimental method of CO and the evaluation method of thermocatalytic efficiency.The invention has the characteristics that: the catalyst is first to prepare graphene oxide using flaky graphite as presoma referring to the method for Hummers, then prepare various oxides, prepare oxide composite graphite alkene catalyst finally by Chemical peeling method.The catalyst stability is good, and dispersibility is strong and it heat-treats CO₂The catalytic efficiency for synthesizing CO is much higher than pure-oxide and graphene；This method is carried out in the closed glass reactor of (no light) under cryogenic, have many advantages, such as equipment requirement it is low, it is easy to operate, without illumination, Yi Yingyong.The present invention will open up new direction to prepare novel efficient thermocatalyst and in the application of Environment control and new energy field.

Description

It is a kind of to heat-treat CO using graphene-based catalyst2The method for synthesizing CO

[technical field]

CO is heat-treated using graphene-based catalyst the invention discloses a kind of₂The method for synthesizing CO, the heat of the catalyst Catalysis reduction CO₂The efficiency for synthesizing CO is much higher than pure-oxide and graphene.The invention belongs to thermocatalytic technical fields, to utilize Catalysis technique reduction carbon dioxide and water prepare carbon monoxide and provide a kind of novel and easy method.

[background technique]

Environmental pollution and energy shortage have become the main crisis that the world today faces, and people constantly probe into Environment control With the new method of exploitation renewable energy.In 1972, Fujishima and Honda report used TiO₂Optoelectronic pole and platinum electrode Composition optical electro-chemistry system breaks water into hydrogen and oxygen, so that opening semiconductor is catalyzed this new research field.Closely A little years, by CO₂It is reduced into the research hotspot that hydrocarbon fuel has become energy environment scientific domain.The research is for development and utilization CO in renewable energy and removal atmosphere₂Gas, reducing greenhouse effects has important scientific meaning.

The present invention discloses a kind of graphene-based catalyst of utilization and heat-treats CO₂The method for synthesizing CO.This method is to utilize to grind The graphene-based catalyst of system heat-treats CO under cryogenic₂CO is synthesized, and this method condition requires simply, to be not necessarily to illumination And application is strong；Carbon dioxide is restored using the catalyst thermo-catalytic and water generates carbon monoxide, and thermocatalytic efficiency is much higher than Pure-oxide and graphene.Currently, the research work that thermocatalytic reduction carbon dioxide and water prepare carbon monoxide under low temperature has no Report, the research achievement will open up new direction for Environment control and the fields of grade that tap a new source of energy.

[summary of the invention]

CO is heat-treated using graphene-based catalyst the invention discloses a kind of₂The method for synthesizing CO, summary of the invention packet Include following aspect: 1., first using flaky graphite as presoma, prepare graphene oxide referring to the method for Hummers, then prepare Various oxides out obtain oxide composite graphite alkene catalyst finally by Chemical peeling legal system.The catalysis is utilized 2. establishing Agent effectively heat-treats CO under cryogenic (25~90 DEG C)₂It synthesizes the experimental method of CO and generates the evaluation side of CO efficiency Method.3. carrying out thermal reduction CO using graphene-based catalyst₂Synthesize the experiment of CO.The result shows that: graphene-based catalyst is low There is very high thermocatalytic efficiency, thermocatalytic efficiency is much higher than pure-oxide and graphene under the conditions of temperature；This method technique letter The requirement of single and implementation condition is low, and easy to operate and application is strong, and the active evaluation method of thermocatalytic is accurately feasible.

It is of the invention that the specific method is as follows:

1. the preparation of graphite alkenyl nanometer materials

First using flaky graphite as presoma, graphene oxide is prepared referring to the method for Hummers, is then prepared various Oxide obtains oxide composite graphite alkene catalyst finally by Chemical peeling legal system.

2. thermocatalytic restores CO₂It synthesizes the experimental method of CO and generates the evaluation method of CO efficiency

Thermocatalytic restores CO₂And H₂The experiment of O is carried out in 280ml cylindrical type glass reactor under cryogenic.It is first 100mg catalyst is first weighed, is laid on the glass slide of 2.5 × 7.5cm.Glass slide is placed in reactor center again.Then past CO is passed through in reactor₂Gas, gas purity 99.999%, flow 0.2Lmin^-1, time 35min, to exclude Air in reactor simultaneously makes CO₂Gas reaches saturation.1.5ml deionized water is injected after inflation in reactor and is sealed Mouthful.It recently will be in the fixed thermostatic drying chamber under cryogenic of entire reaction system.0.4ml in 4h abstraction reaction device Gas, using the concentration of gas chromatograph for determination product CO, and carried out in contrast with the heat seal of no catalyst under the same conditions Experiment.

Further technical solution is that the cryogenic conditions are 25~90 DEG C.

Further technical solution is that the oxide can be WO₃, ZnO, ZrO₂, CeO₂, MnO₂Or TiO₂In Any one.

For a better understanding of the present invention, the present invention is described in further detail below with reference to embodiment, but this hair Bright claimed range is not limited to range represented by embodiment.

[Detailed description of the invention]

The XRD spectrum of sample in Fig. 1 embodiment 1；

The thermocatalytic of sample restores CO in Fig. 2 embodiment 1₂Synthesize the activity figure of CO；

20%WO under different temperatures in Fig. 3 embodiment 1₃The thermocatalytic activity figure of/graphene sample；

The thermocatalytic of sample restores CO in Fig. 4 embodiment 2₂Synthesize the activity figure of CO；

The present invention is described further below in conjunction with specific embodiments and the drawings, and illustrates thermocatalytic of the invention Effect.

[specific embodiment]

Embodiment 1

WO₃Preparation: claim 3g sodium tungstate and 0.01g cetyl trimethylammonium bromide (CTAB), be dissolved in 10mL deionization In water.After stirring 0.5h, solution PH=0.3 is adjusted with 3mol/L HCl.Continue to stir 1h, is transferred in reaction kettle and fills 80%, it is placed for 24 hours at 120 DEG C of thermostatic drying chamber case.Centrifugal sedimentation, gained precipitating distilled water, acetone wash repeatedly, in 60 DEG C Dry 10h.WO is made in finally 300 DEG C of calcination 3h in Muffle furnace₃Powder.

It is as follows that Hummers method prepares the specific process flow of graphite oxide: graphene composite titanium dioxide based nano-material The preparation method is as follows: assembling the beaker of 1L in ice-water bath, the concentrated sulfuric acid of 115mL is added.5g squama is added under continuous stirring The solid mixture of piece graphite and 2.5g sodium nitrate, then 15g potassium permanganate is added by several times, control reaction temperature is no more than 20 DEG C. Then liquid is warming up to 35 DEG C, continues to stir 60min.It is slow added into the deionized water of 230mL, liquid acutely boils and protects Temperature is held in 98 DEG C or so 15min.And 0.7L distilled water and 12.5mL hydrogen peroxide is added, finally with 1L 5%HCl solution and going Ion water washing is until sulfate radical-free is detected in filtrate.It is finally sufficiently dry in 60 DEG C of vacuum oven, it obtains To graphene oxide.

WO₃/ graphene method for preparing catalyst is as follows: in mass ratio 1: 9~1: 1 is placed in WO3 and graphene oxide In 500ml beaker, 280ml dehydrated alcohol, room temperature ultrasound 1h is added.Then 2ml NaOH solution (8mol/L) is added, continues to surpass Sound 5h, temperature remain 75 DEG C.It is stood after ultrasound for 24 hours, supernatant liquor is outwelled, finally cleaned 5 times with ethyl alcohol, 50 It is dry at DEG C, obtain WO₃/ graphene catalyst.

Embodiment 2

The preparation of ZnO: claim to add in 3.67g zinc nitrate and 0.1g cetyl ammonium bromide solution 50ml deionized water 50ml sodium carbonate liquor (0.25mol/L).2h is persistently stirred, reacts two kinds of solution sufficiently.Centrifugation, washing are dry in 60 DEG C It is dry, obtain basic zinc carbonate.2.5h finally is calcined in 600 DEG C of Muffle furnace, ZnO sample is made.

Remaining experiment condition, step are the same as embodiment 1.

Attached drawing is described briefly below:

Fig. 1 shows to be successfully prepared out WO₃, graphene and WO₃/ graphene catalyst.

Fig. 2 shows pure WO₃Thermocatalytic restore CO₂The activity for synthesizing CO is very low, and only 0.155 μm of ol CO is generated.When anti- After answering 32 hours, it is 1.03 μm of ol that pure graphene, which generates CO amount,.For compound sample, 20%WO₃/ graphene performance Highest thermocatalytic activity out, has the CO of 4.53 μm of ol to generate, thermocatalytic activity is pure WO respectively₃With the 29 of graphene Times and 4.5 times.

Fig. 3 shows to increase with temperature, 20%WO₃/ graphene sample thermocatalytic activity also correspondinglys increase.

Fig. 4 is the thermocatalytic activity figure of ZnO/graphene series of samples.The result shows that after compound, 15%ZnO/ Graphene sample thermocatalytic activity highest, reaction 10 hours after have 2.38 μm of ol CO generate, be respectively pure ZnO and 65.5 times of graphene and 4.1 times.

As can be seen that oxide composite graphite alkene sample is compared with pure-oxide with graphene from above example, heat The catalytic activity of reduction CO2 synthesis CO is greatly improved.

Claims (1)

1. a kind of heat-treat CO using graphene-based catalyst₂The method for synthesizing CO, it is characterised in that: graphene-based including preparing Catalyst prepares graphene oxide referring to the method for Hummers, then prepares various first using flaky graphite as presoma Oxide and graphene oxide finally in mass ratio 1: 9~1: 1 are placed in 500ml beaker by oxide, and it is anhydrous that 280ml is added Ethyl alcohol, room temperature ultrasound 1h, the concentration that 2ml is added later is the NaOH solution of 8mol/L, continues ultrasound 5h, temperature remains 75 ℃；It is stood after ultrasound for 24 hours, supernatant liquor is outwelled, cleaned 5 times with ethyl alcohol, it is dry at 50 DEG C, it is compound that oxide is made Graphen catalyst；Thermocatalytic restores CO₂Synthesis CO is carried out in 280ml cylindrical type glass reactor under cryogenic 's；The catalyst for weighing 100mg first, is laid on the glass slide of 2.5 × 7.5cm；Glass slide is placed in reactor center again； Then CO is passed through into reactor₂Gas, gas purity 99.999%, flow 0.2Lmin^-1, time 35min, use To exclude the air in reactor and make CO₂Gas reaches saturation, and inflation injects 1.5ml deionized water into reactor after terminating And it seals；Finally entire reaction system is fixed in thermostatic drying chamber under cryogenic, every in 4h abstraction reaction device The gas of 0.4ml, using the concentration of gas chromatograph for determination product CO, wherein cryogenic conditions are 50~90 DEG C, oxide WO₃ Or ZnO.

Images