阅读说明：本技术 钴基氧化物负载双掺杂石墨烯催化剂及其制备方法和应用 (Cobalt-based oxide supported double-doped graphene catalyst and preparation method and application thereof ) 是由 蔡松韬 黄莹秀 曾盛渠 李文军 吴智 杨霆宇 何周颖 熊湘 杨绍轩 于 2020-12-15 设计创作，主要内容包括：钴基氧化物负载双掺杂石墨烯催化剂及其制备方法和应用,涉及负载型催化材料技术领域。其中,前述钴基氧化物负载双掺杂石墨烯催化剂由N,S双掺杂的石墨烯作为载体负载四氧化三钴纳米颗粒构成,其中包含有Co-S和Co-N两种配位结构。上述钴基氧化物负载双掺杂石墨烯催化剂具有非常优异的一氧化碳氧化催化性能,在汽车尾气处理、传感器、石油化工等领域会有广泛的应用前景。(A cobalt-based oxide supported double-doped graphene catalyst and a preparation method and application thereof relate to the technical field of supported catalytic materials. The cobalt-based oxide supported double-doped graphene catalyst is formed by taking N and S double-doped graphene as a carrier to support cobaltosic oxide nanoparticles, and comprises two coordination structures of Co-S and Co-N. The cobalt-based oxide supported double-doped graphene catalyst has excellent carbon monoxide oxidation catalytic performance, and has wide application prospects in the fields of automobile exhaust treatment, sensors, petrochemical industry and the like.)

1. The cobalt-based oxide supported double-doped graphene catalyst is characterized in that: the graphene-supported cobaltosic oxide nanoparticle is formed by taking N and S double-doped graphene as a carrier to load cobaltosic oxide nanoparticles, and comprises two coordination structures of Co-S and Co-N.

2. A method for preparing the cobalt-based oxide-supported double-doped graphene catalyst according to claim 1, wherein:

soaking the nitrogen-doped graphene in chlorosulfonic acid solution for 1-2h, centrifuging the obtained reaction solution, and freeze-drying to obtain a double-doped graphene carrier;

preparing a cobalt salt solution, adding the double-doped graphene into the cobalt salt solution, carrying out a solvothermal reaction at the temperature of 140-180 ℃, reacting for 6-8h, centrifuging, freeze-drying, and calcining under the protection of nitrogen to obtain the cobalt-based oxide supported double-doped graphene catalyst.

3. The method for preparing a cobalt-based oxide-supported double-doped graphene catalyst according to claim 2, further comprising the step of preparing nitrogen-doped graphene: adding graphene oxide into an ammonium acetate solution, uniformly dispersing, carrying out reflux reaction for 2-3h at the temperature of 60-80 ℃, and centrifuging and freeze-drying the obtained reaction solution to obtain the nitrogen-doped graphene.

4. The method of preparing a cobalt-based oxide-supported double-doped graphene catalyst according to claim 2, wherein: the concentration of the cobalt salt solution is 0.15-0.30 g/L.

5. The method of preparing a cobalt-based oxide-supported double-doped graphene catalyst according to claim 2, wherein: the cobalt salt is one of cobalt acetate and cobalt acetylacetonate.

6. The method of preparing a cobalt-based oxide-supported double-doped graphene catalyst according to claim 2, wherein: the concentration of the chlorosulfonic acid solution is 0.4-0.5 mol/L.

7. The method of preparing a cobalt-based oxide-supported double-doped graphene catalyst according to claim 3, wherein: the concentration of the ammonium acetate is 0.2-0.3mol/L, and the solvent is isopropanol or glycerol.

8. The method of preparing a cobalt-based oxide-supported double-doped graphene catalyst according to claim 2, wherein: the mass ratio of the double-doped graphene carrier to the cobalt salt in the solvothermal reaction is (0.5-1): (0.15-0.3).

9. The method of preparing a cobalt-based oxide-supported double-doped graphene catalyst according to claim 2, wherein: the calcining temperature under the protection of nitrogen is 200-400 ℃, and the calcining time is 1-2 h.

10. Use of the cobalt-based oxide supported double doped graphene catalyst of claim 1 as a carbon monoxide oxidation catalyst.

Technical Field

The invention relates to the technical field of supported catalytic materials, in particular to a cobalt-based oxide supported double-doped graphene catalyst and a preparation method and application thereof.

Background

Graphene is a two-dimensional nano material with a honeycomb hexagonal lattice structure formed by sp2 hybridized carbon atoms, and the unique structure enables the graphene to have excellent thermal, mechanical and electrical properties, but the application of intrinsic graphene in the electronic field is limited by the zero band gap characteristic of the intrinsic graphene, and the graphene with the adjustable band gap in a certain range is particularly important to obtain. In order to open the band gap of graphene, many methods are explored, such as cutting graphite into quantum dots, nanobelts, nanograms or laying graphene on a special substrate, wherein one of the most feasible methods is to adjust the physicochemical property of graphene through doping.

The CO oxidation reaction is an important reaction in air pollution control, especially in the treatment of automobile exhaust. In petrochemical industry, catalytic oxidation of CO is involved in the oxidation and regeneration process of a catalyst, and in order to prevent CO from burning and damaging equipment in subsequent processes, the CO is required to be completely oxidized in a coking process. In addition, in the energy metallurgy industry, the downhole gas also contains a certain amount of CO, and for this purpose, a gas mask capable of adsorbing CO needs to be specially designed. Therefore, if a high-efficiency CO oxidation catalyst can be developed, the development potential and the prospect are huge.

Disclosure of Invention

One of the objects of the present invention is to provide a catalyst having high oxidation catalytic performance for CO.

In order to solve the technical problems, the invention adopts the following technical scheme: a cobalt-based oxide loaded double-doped graphene catalyst is composed of N, S double-doped graphene serving as a carrier and loaded with cobaltosic oxide nanoparticles, and comprises two coordination structures of Co-S and Co-N.

In addition, the invention also relates to a method for preparing the cobalt-based oxide supported double-doped graphene catalyst, which comprises the following steps:

soaking the nitrogen-doped graphene in chlorosulfonic acid solution for 1-2h, centrifuging the obtained reaction solution, and freeze-drying to obtain a double-doped graphene carrier;

preparing a cobalt salt solution, adding the double-doped graphene into the cobalt salt solution, carrying out a solvothermal reaction at the temperature of 140-180 ℃, reacting for 6-8h, centrifuging, freeze-drying, and calcining under the protection of nitrogen to obtain the cobalt-based oxide supported double-doped graphene catalyst.

In addition to the above steps, the method may further include the step of preparing the nitrogen-doped graphene: adding graphene oxide into an ammonium acetate solution, uniformly dispersing, carrying out reflux reaction for 2-3h at the temperature of 60-80 ℃, and centrifuging and freeze-drying the obtained reaction solution to obtain the nitrogen-doped graphene.

Wherein the concentration of the cobalt salt solution is 0.15-0.30 g/L.

Wherein, the cobalt salt is one of cobalt acetate and cobalt acetylacetonate.

Wherein the concentration of the chlorosulfonic acid solution is 0.4-0.5 mol/L.

Wherein the concentration of the ammonium acetate is 0.2-0.3mol/L, and the solvent is isopropanol or glycerol.

Preferably, the mass ratio of the double-doped graphene carrier to the cobalt salt in the solvothermal reaction is (0.5-1): (0.15-0.3).

Further, the temperature of the calcination under the protection of nitrogen is 200-400 ℃, and the calcination time is 1-2 h.

Finally, the invention also relates to an application of the cobalt-based oxide supported double-doped graphene catalyst as a carbon monoxide oxidation catalyst.

According to the method, N atoms and S atoms are respectively used as electron donors and acceptors to dope graphene in a substitution mode, and the N and S double-doped graphene is creatively used as a carrier to load cobaltosic oxide nanoparticles to generate two unique coordination structures, namely Co-S and Co-N, so that the electron transfer rate is dramatically improved, and the performance is far better than that of a scheme of using single N and S doped graphene as a carrier. The cobalt-based oxide loaded double-doped graphene catalyst prepared by the invention has very excellent catalytic performance and has wide application prospects in the fields of automobile exhaust treatment, sensors, petrochemical industry and the like.

Drawings

Fig. 1 is a transmission electron microscope image of a cobalt-based oxide-supported double-doped graphene catalyst obtained in example 1.

FIG. 2 is a graph of CO catalytic reaction curves corresponding to different catalysts, wherein: the square corresponds to a cobalt-based oxide loaded double-doped graphene catalyst; a circular corresponding cobalt-based oxide loaded nitrogen-doped graphene catalyst; a sulfur-doped graphene catalyst is loaded on a cobalt-based oxide corresponding to a triangle; the rhombus corresponds to a cobalt-based oxide loaded undoped graphene catalyst.

FIG. 3 is a schematic structural view of a CO oxidation reaction catalytic performance evaluation apparatus.

Detailed Description

In order that those skilled in the art will better understand the difference between the present invention and the prior art, the present invention will be further described with reference to the following specific examples, which are not to be construed as limiting the present invention.

Firstly, preparing a cobalt-based oxide loaded double-doped graphene catalyst.

1. Adding a proper amount of graphene oxide into 0.2-0.3mol/L (in the embodiment, 0.25 mol/L) ammonium acetate solution, uniformly dispersing, performing reflux reaction for 2h at 60-80 ℃ (in the embodiment, 80 ℃) (if the temperature is lower than 80 ℃, the reaction time can be properly prolonged to 3 h), centrifuging the obtained reaction solution, and freeze-drying to obtain the nitrogen-doped graphene.

2. And (3) soaking the nitrogen-doped graphene in a prepared 0.4-0.5 mol/L (0.45 mol/L is selected in the embodiment) chlorosulfonic acid solution for 1-2h, and centrifuging and freeze-drying the obtained reaction solution to obtain the double-doped graphene carrier.

3. Using isopropanol or glycerol as solvent, and preparing at 0.15-0.30 g/L(0.30 g/L is selected in the embodiment) of cobalt salt solution, and an appropriate amount (0.5 g is selected in the embodiment) of double-doped graphene is added to the cobalt salt solution to carry out the solvothermal reaction, and it should be noted that the mass ratio of the double-doped graphene carrier to the cobalt salt in the solvothermal reaction is (0.5-1): (0.15-0.3), reacting for 6-8h under 140-^oC) Calcining for 1-2h to obtain the cobalt-based oxide supported double-doped graphene catalyst.

And secondly, detecting the activity of the catalyst for catalyzing and oxidizing the carbon monoxide.

The activity of the catalyst in catalyzing and oxidizing carbon monoxide is detected by adopting a self-made CO oxidation reaction catalysis performance evaluation device shown in figure 3. As shown in the figure, the device for evaluating the catalytic performance of the CO oxidation reaction consists of a glass reaction tube 1, a tubular resistance furnace 2, a mass flow meter 3, a gas cylinder 4, a tail gas treatment box 5, a heating device 6, a six-way valve 7 and a gas chromatograph 8. A glass reaction tube 1 is arranged in the tubular resistance furnace 2, one end of the glass reaction tube 1 is connected with a gas cylinder 4, the other end of the glass reaction tube 1 is sequentially connected with a mass flow meter 3 and a six-way valve 7, and the six-way valve 7 is respectively connected with a gas chromatograph 8 and a tail gas treatment box 5; a heating device 6 is arranged in the tail gas treatment box 5. The glass reaction tube 1 is provided by Xiamen university glass factory, the specification is phi 8 x 1mm, the tubular resistance furnace 2 is provided by Synfei Kejing technology Co., Ltd, the model is GWL1600A, the mass flow meter 3 is provided by Beijing Qixinhua Hua Chuang electronic corporation, the model is D07-7B, the gas cylinder 4 is provided by Hangzhou gold gas factory, the volume is 40L, the tail gas treatment device comprises a tail gas treatment box 5 and an internal heating device 6, and is provided by Yichang Guiyuan environmental protection equipment manufacturing company, the model is DOC50, the six-way valve 7 is purchased from hardware stores, the diameter is 10.5mm, the gas chromatograph 8 is provided by Hangzhou Keke technology Co., Ltd, and the model is GC 1690. The chromatographic conditions include carrier gas column pressure (Ar) of 0.1MPa, chromatographic column of 5A, column length of 3m, column temperature of 90 deg.c and bridge flow of 70 mA. CO and O are filled in the gas cylinder 4₂、N₂By gas chromatograph 8, O is detected₂，N₂And the peak area data of the CO, and calculating to obtain the conversion rate of the CO. Such asThis repetition, when the peak of CO disappears, indicates that the conversion of CO reaches 100%, and the time is started until the peak of CO appears again, and finally the duration of the catalyst activity is obtained to evaluate the catalytic activity of the catalyst on carbon monoxide.

In the catalyst activity detection process in this example, the following were performed: 0.1g of the prepared catalyst is put into a glass reaction tube and introduced with CO to O in volume ratio₂:N₂The air in the tube was first evacuated by passing the mixed gas for 5 minutes, which was 1:1: 98. Then accurately regulating the flow rate of the gas through a mass flow meter, controlling the flow rate to be 6mL/min, setting the temperature rise parameter of the tubular resistance furnace to be 2 ℃/min, and taking a sample every 2.5min to perform O₂,N₂And analyzing CO peak, wherein the six-way valve is communicated with a gas chromatography sample inlet during sampling, 2mL of reaction mixed gas is collected by chromatography, a valve communicated with the chromatography sample inlet is closed after collection is finished, the collected sample is analyzed by gas chromatography with a 5A column (TCD detector), and then O is analyzed₂,N₂And calculating the conversion rate of the CO according to the peak area data of the CO. Repeating the steps, when the peak of CO disappears, indicating that the conversion rate of CO reaches 100%, starting to time until the peak of CO appears again, and obtaining the activity duration of the catalyst. After the detection is finished, the residual gas is connected into a tail gas treatment device through a six-way valve, and CO is converted into CO through a heating device₂。

Through detection, the cobalt-based oxide supported double-doped graphene catalyst prepared by the embodiment is completely converted at 60 ℃, can maintain stability for 50 hours, and has no obvious attenuation.

Comparative example 1

Firstly, preparing a cobalt-based oxide loaded nitrogen-doped graphene catalyst.

1. Adding a proper amount of graphene oxide into 0.25mol/L ammonium acetate solution, uniformly dispersing, carrying out reflux reaction for 2 hours at 80 ℃, centrifuging the obtained reaction solution, and freeze-drying to obtain the nitrogen-doped graphene.

2. Preparing 0.30 g/L cobalt salt solution, adding 0.5g of nitrogen-doped graphene into the solution, performing solvothermal reaction at 140 ℃ for 6 hours, centrifuging, freeze-drying, and performing 300-hour reaction under the protection of nitrogen ^oAnd C, calcining for 2 hours to obtain the cobalt-based oxide loaded nitrogen-doped graphene catalyst.

And secondly, detecting the activity of the catalyst for catalyzing and oxidizing the carbon monoxide.

In the comparative example, the equipment and method for detecting the activity of the catalyst for catalytic oxidation of carbon monoxide are the same as those in the example, and are not described again.

Through detection, the cobalt-based oxide loaded nitrogen-doped graphene catalyst prepared in the comparative example is completely converted at 150 ℃, and can be maintained stable for 30 h.

Comparative example 2

Firstly, preparing a cobalt-based oxide-supported sulfur-doped graphene catalyst.

1. And adding a proper amount of graphene oxide into a prepared 0.45mol/L chlorosulfonic acid solution, soaking for 1h, centrifuging the obtained reaction solution, and freeze-drying to obtain the sulfur-doped graphene carrier.

2. Preparing 0.30 g/L cobalt salt solution, adding 0.5g of sulfur-doped graphene into the solution, carrying out solvothermal reaction at 140 ℃ for 6 hours, then carrying out centrifugation and freeze drying, and carrying out 300 hours of reaction under the protection of nitrogen^oAnd C, calcining for 2h to obtain the cobalt-based oxide loaded sulfur-doped graphene catalyst.

And secondly, detecting the activity of the catalyst for catalyzing and oxidizing the carbon monoxide.

In the comparative example, the equipment and method for detecting the activity of the catalyst for catalytic oxidation of carbon monoxide are the same as those in the example, and are not described again.

Through detection, the cobalt-based oxide loaded nitrogen-doped graphene catalyst prepared in the comparative example is completely converted at 180 ℃, and can be maintained stable for 23 h.

Comparative example 3

Firstly, preparing a cobalt-based oxide loaded undoped graphene catalyst.

Preparing 0.30 g/L cobalt salt solution, adding 0.5g of undoped graphene into the solution, performing solvothermal reaction at 140 ℃ for 6 hours, centrifuging, freeze-drying, and performing 300-hour reaction under the protection of nitrogen^oAnd C, calcining for 2 hours to obtain the cobalt-based oxide supported graphene catalyst.

In the comparative example, the equipment and method for detecting the activity of the catalyst for catalytic oxidation of carbon monoxide are the same as those in the example, and are not described again.

Through detection, the cobalt-based oxide loaded graphene catalyst prepared by the comparative example is completely converted at 270 ℃, and can be stable for 6 hours.

From the above detection results and with reference to FIG. 2, it can be seen that the catalyst prepared by the present invention is used for catalytic oxidation of carbon monoxide in the presence of CO in the ratio of O₂Under the condition of 1:1, the conversion rate of 100% can be achieved at 60 ℃, the reaction lasts for more than 50h, the activity and the stability are good, and the catalytic effect is far better than that of other comparative examples.

Compared with the prior art, the process for preparing the cobalt-based oxide supported double-doped graphene catalyst is very simple, the N atom and the S atom are respectively used as an electron donor and an electron acceptor to be doped with graphene in a substitution mode, the N and S double-doped graphene is creatively used as a carrier to load cobaltosic oxide nanoparticles, two unique coordination structures (Co-S and Co-N respectively) are generated, the electron transfer rate is dramatically improved, and the performance is far better than that of a scheme using single N and S doped graphene as a carrier. The cobalt-based oxide loaded double-doped graphene catalyst has excellent catalytic performance, and has wide application prospects in the fields of automobile exhaust treatment, sensors, petrochemical industry and the like.