Preparation method of monatomic catalyst based on biomass derived carbon

Abstract

The invention discloses a preparation method of a monatomic catalyst based on biomass-derived carbon, raw materials comprise bagasse and antimony triacetate, and the preparation process mainly comprises the following steps: (1) cleaning the bagasse, draining, soaking in dilute nitric acid, filtering, cleaning to be neutral, airing, putting into a high-pressure reaction kettle, adding distilled water, and reacting for 2-4 hours; treating in an electrothermal blowing drying box, then taking out and washing, and staying overnight in a vacuum drying box at 80 DEG C to obtain black powder; (2) fully grinding and mixing the black powder and a proper amount of antimony triacetate, and performing high-temperature pyrolysis on the obtained mixture in a tubular furnace in a nitrogen atmosphere to obtain black powder; and (3) adding into 0.1 M hydrochloric acid, stirring, carrying out suction filtration and washing with distilled water until the solution is neutral, and putting into a vacuum oven for overnight at 80 DEG C. The used raw materials are low in cost, the preparation process is simple, and the antimony triacetate activated bagasse derived carbon loaded monatomic antimony catalyst has extremely excellent oxygen reduction reaction electro-catalysis performance.

Description

Technical Field

[0001] The invention relates to the technical field of biomass-derived carbon, and in particular to a method for preparing a single-atom catalyst based on biomass-derived carbon. Background Art

[0002] A large amount of domestic waste is generated in daily life, and much of it is produced by crops rich in carbon. After drying, it can be pyrolyzed at high temperature in an airtight environment to be converted into doped carbon materials. These doped carbon materials can be further processed to effectively catalyze the oxygen reduction reaction (ORR) and be used in fuel cells and metal-air batteries, promoting the development of new energy and the realization of the country's dual carbon goals.

[0003] Sugarcane is the main raw material for the sugar industry. A large amount of bagasse is produced during the production process, which needs to be processed. The main component of bagasse is fiber. Carbon material is obtained after high-temperature pyrolysis in a nitrogen atmosphere. Pore expansion treatment during the pyrolysis process can effectively improve its pore structure and surface composition, so that it can obtain a large specific surface area and surface defects, creating conditions for it to act as an electrocatalyst. However, due to the lack of surface active sites, its catalytic activity needs to be improved. In our experiments, we found that loading cheap single-atom metal atoms on its surface can provide more active sites to adsorb and dissociate reactant molecules, thereby greatly improving its electrocatalytic activity. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a single-atom catalyst based on biomass-derived carbon to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a single-atom catalyst based on biomass-derived carbon, wherein the raw materials include bagasse and antimony triacetate, and the preparation process mainly includes the following steps:

[0007] (1) Weighing bagasse, soaking and washing with distilled water, draining, soaking in dilute nitric acid for 12 hours, filtering the bagasse, repeatedly washing the bagasse with distilled water until neutral and air-drying, weighing an appropriate amount of the air-dried bagasse, putting it into a high-pressure reactor, adding an appropriate amount of distilled water, placing it in an electric heating blast drying oven at 190° C. for 12 hours, then taking it out, washing it, and then placing it in a vacuum drying oven at 80° C. overnight to obtain a black powder;

[0008] (2) the black powder obtained in step (1) is fully ground and mixed with an appropriate amount of antimony triacetate, and the resulting mixture is placed in a tube furnace under a nitrogen atmosphere and heated to 800° C. for 1 hour, then heated to 1100° C. for 2 hours, then cooled to 800° C. for 1 hour, and finally cooled to room temperature to obtain a black powder;

[0009] (3) The black powder obtained in step (2) was taken out and added into 0.1 M hydrochloric acid, and reacted for 24 hours under stirring. Then, the powder was filtered and washed with distilled water until neutral, and placed in a vacuum oven at 80° C. overnight to obtain a sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate.

[0010] As a further solution of the present invention: the dilute nitric acid in step (1) is nitric acid: distilled water = 1:6.

[0011] Compared with the prior art, the present invention has the following beneficial effects: the raw materials used in the present invention are cheap, the preparation process is simple, and the obtained antimony triacetate-activated bagasse-derived carbon-supported single-atom antimony catalyst has extremely excellent electrocatalytic performance for oxygen reduction reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 XRD of antimony triacetate activated bagasse samples obtained by pyrolysis at different temperatures.

[0013] Figure 2 Scanning electron microscope (SEM), transmission electron microscope (TEM), scanning transmission electron microscope (STEM), element distribution and high-resolution HAADF-STEM images of the sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate obtained by pyrolysis at 1100°C.

[0014] Figure 3 Nitrogen adsorption-desorption isotherms and pore size distribution curves of antimony triacetate activated bagasse samples obtained by pyrolysis at different temperatures.

[0015] Figure 4 CV curves of bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate in N2 or O2 saturated KOH solution.

[0016] Figure 5 LSV comparison of antimony triacetate activated bagasse-derived carbon-supported antimony catalyst prepared at different pyrolysis temperatures and commercial Pt / C for oxygen reduction reaction.

[0017] Figure 6 LSV curves of sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate at different rotation speeds and KL curves at different potentials.

[0018] Figure 7The chronoamperometric curves and methanol resistance curves of sugarcane bagasse-derived carbon-supported single-atom antimony catalyst and Pt / C activated by antimony triacetate at 0.7V. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Embodiment 1

[0021] A method for preparing a single-atom catalyst based on biomass-derived carbon, wherein the raw materials include bagasse and antimony triacetate, and the preparation process mainly includes the following steps:

[0022] Step 1: Weigh the bagasse, soak it in distilled water, wash it, drain it, soak it in dilute nitric acid (nitric acid: distilled water = 1:6) for 12 hours, filter the bagasse, wash it repeatedly with distilled water until it is neutral and air-dry it, weigh an appropriate amount of the air-dried bagasse, put it into a high-pressure reactor, add an appropriate amount of distilled water, place it in an electric blast drying oven at 190°C for 12 hours, then take it out and wash it, and then place it in a vacuum drying oven at 80°C overnight to obtain a black powder;

[0023] Step 2: The black powder obtained in the above step is fully ground and mixed with an appropriate amount of antimony triacetate, and the resulting mixture is placed in a tube furnace and heated to 800° C. under a nitrogen atmosphere, maintained for 1 hour, then heated to 1000° C., maintained for 2 hours, then cooled to 800° C., maintained for 1 hour, and finally cooled to room temperature and taken out to obtain a black powder;

[0024] Step 3: Take out the black powder obtained in step 2 and add it to 0.1M hydrochloric acid, react for 24 hours under stirring, then filter and wash with distilled water until neutral, put it in a vacuum oven at 80°C overnight to obtain a sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate.

[0025] Embodiment 2

[0026] A method for preparing a single-atom catalyst based on biomass-derived carbon, wherein the raw materials include bagasse and antimony triacetate, and the preparation process mainly includes the following steps:

[0027] Step 1: Weigh the bagasse, soak it in distilled water, wash it, drain it, soak it in dilute nitric acid (nitric acid: distilled water = 1:6) for 12 hours, filter the bagasse, wash it repeatedly with distilled water until it is neutral and air-dry it, weigh an appropriate amount of the air-dried bagasse, put it into a high-pressure reactor, add an appropriate amount of distilled water, place it in an electric blast drying oven at 190°C for 12 hours, then take it out and wash it, and then place it in a vacuum drying oven at 80°C overnight to obtain a black powder;

[0028] Step 2: The black powder obtained in the above step is fully ground and mixed with an appropriate amount of antimony triacetate, and the resulting mixture is placed in a tube furnace and heated to 800° C. under a nitrogen atmosphere, maintained for 1 hour, then heated to 1100° C., maintained for 2 hours, then cooled to 800° C., maintained for 1 hour, and finally cooled to room temperature to obtain a black powder;

[0029] Step 3: Take out the black powder obtained in step 2 and add it to 0.1M hydrochloric acid, react for 24 hours under stirring, then filter and wash with distilled water until neutral, put it in a vacuum oven at 80°C overnight to obtain a sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate.

[0030] Embodiment 3

[0031] A method for preparing a single-atom catalyst based on biomass-derived carbon, wherein the raw materials include bagasse and antimony triacetate, and the preparation process mainly includes the following steps:

[0032] Step 1: Weigh the bagasse, soak it in distilled water, wash it, drain it, soak it in dilute nitric acid (nitric acid: distilled water = 1:6) for 12 hours, filter the bagasse, wash it repeatedly with distilled water until it is neutral and air-dry it, weigh an appropriate amount of the air-dried bagasse, put it into a high-pressure reactor, add an appropriate amount of distilled water, place it in an electric blast drying oven at 190°C for 12 hours, then take it out and wash it, and then place it in a vacuum drying oven at 80°C overnight to obtain a black powder;

[0033] Step 2: The black powder obtained in the above step is fully ground and mixed with an appropriate amount of antimony triacetate, and the resulting mixture is placed in a tube furnace and heated to 800° C. under a nitrogen atmosphere, maintained for 1 hour, then heated to 1200° C., maintained for 2 hours, then cooled to 800° C., maintained for 1 hour, and finally cooled to room temperature to obtain a black powder;

[0034] Step 3: Take out the black powder obtained in step 2 and add it to 0.1M hydrochloric acid, react for 24 hours under stirring, then filter and wash with distilled water until neutral, put it in a vacuum oven at 80°C overnight to obtain a sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate.

[0035] Example 4

[0036] A method for preparing a single-atom catalyst based on biomass-derived carbon, wherein the raw materials include bagasse and antimony triacetate, and the preparation process mainly includes the following steps:

[0037] Step 1: Weigh the bagasse, soak it in distilled water, wash it, drain it, soak it in dilute nitric acid (nitric acid: distilled water = 1:6) for 12 hours, filter the bagasse, wash it repeatedly with distilled water until it is neutral and air-dry it, weigh an appropriate amount of the air-dried bagasse, put it into a high-pressure reactor, add an appropriate amount of distilled water, place it in an electric blast drying oven at 190°C for 12 hours, then take it out and wash it, and then place it in a vacuum drying oven at 80°C overnight to obtain a black powder;

[0038] Step 2: The black powder obtained in the above step is fully ground and mixed with an appropriate amount of antimony triacetate, and the resulting mixture is placed in a tube furnace and heated to 800° C. under a nitrogen atmosphere, maintained for 1 hour, then heated to 900° C., maintained for 2 hours, then cooled to 800° C., maintained for 1 hour, and finally cooled to room temperature to obtain a black powder;

[0039] Step 3: Take out the black powder obtained in step 2 and add it to 0.1M hydrochloric acid, react for 24 hours under stirring, then filter and wash with distilled water until neutral, put it in a vacuum oven at 80°C overnight to obtain a sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate.

[0040] Figure 1 These are the XRD results of antimony triacetate activated bagasse samples obtained by pyrolysis at different temperatures. The results show that when the pyrolysis temperature is 900℃, the sample is carbon-loaded antimony, and the diffraction peak of antimony is completely consistent with PDF#85-1324, indicating that it is elemental antimony. At the same time, two weak diffraction peaks of carbon also appear; at 1000℃, the diffraction peak of antimony is significantly weakened, and at 1100℃, the diffraction peak of antimony disappears and two broad diffraction peaks of carbon appear. The diffraction peak of antimony disappears because antimony is highly dispersed into a single atomic state and scattered on the carbon surface; at 1200℃, the weak diffraction peak of antimony reappears, which should be that the single atoms of antimony aggregate again when the temperature rises.

[0041] Figure 2 The SEM, TEM, scanning transmission electron microscopy (STEM), element distribution, and high-resolution HAADF-STEM images of the sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate obtained by pyrolysis at 1100°C show that the sample is an irregular morphology formed by the bonding of nanoparticles. The particle size is between 10 and 25 nm. The bonding between particles forms pores of varying sizes, with relatively more large pores. These structural characteristics are conducive to the exposure of active sites and the transport of electrolytes. Figure 2As shown in (f), some small isolated bright spots with a diameter of 0.1 to 0.2 nm can be seen in the carbon layer. They belong to antimony atoms. Single atoms of antimony are formed on the surface of the carbon on the catalyst.

[0042] Figure 3 The nitrogen adsorption-desorption isotherms and pore size distribution curves of antimony triacetate activated bagasse samples obtained by pyrolysis at different temperatures. The results show that the pyrolysis temperature has a great influence on the specific surface area and pore structure of the obtained samples, but all of them have a typical mesoporous structure.

[0043] Without antimony triacetate activation, the specific surface area of ​​the carbon material pyrolyzed at 1100 °C is very low, only 163.11 m 2 / g, under the condition of ammonium oxalate activation, the specific surface area of ​​the carbon material obtained by pyrolysis was greatly improved, and it was related to the pyrolysis temperature. At 900℃, the specific surface area was 306.29m 2 / g, and the specific surface area at 1000℃ is 440.11m 2 / g, and the specific surface area at 1100℃ is 613.22m 2 / g, and the specific surface area at 1200℃ is 550.85m 2 / g; the pore size distribution of several samples is as follows Figure 3 As shown in (b), at 1100°C, the porosity of the carbon material activated by antimony triacetate is significantly higher than that of the carbon material without antimony triacetate activation and pyrolysis temperatures of 900°C, 1000°C, and 1200°C, reaching 0.505 cm 3 / g. These indicate that the activation effect of antimony triacetate effectively improves the pore structure of bagasse-derived carbon materials and produces a large number of mesopores, which plays a very important role in promoting the mass transfer process in the catalytic process and effectively improves the electrocatalytic activity of carbon materials.

[0044] The carbon material obtained by activation of antimony triacetate and pyrolysis at 1100°C was used to prepare the working electrode. The Ag / AgCl electrode was used as the reference electrode, the platinum wire electrode was used as the counter electrode, and 0.1M KOH was used as the electrolyte. The oxygen reduction reaction electrocatalytic test was carried out by cyclic voltammetry under the condition of oxygen or nitrogen. The results are as follows: Figure 4 As shown in the results, it can be seen that the sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate produces an obvious oxygen reduction peak at 0.858V (vs. RHE), and the peak current reaches 2.92mA / cm2, showing extremely excellent electrocatalytic performance for oxygen reduction reaction.

[0045] Figure 5 is with Figure 4Linear voltammetric scanning curves of different materials obtained by linear voltammetric scanning method under the same conditions. As can be seen from the figure, the initial reduction potentials of bagasse-derived carbon materials without adding activator antimony triacetate, carbon materials with pyrolysis temperature of 900℃, carbon materials with pyrolysis temperature of 1000℃, carbon materials with pyrolysis temperature of 1100℃, carbon materials with pyrolysis temperature of 1200℃ and commercial Pt / C are 0.892V, 0.855V, 0.954V, 0.995V, 0.920V and 0.987V respectively. The bagasse-derived carbon-supported antimony catalysts activated by antimony triacetate all show higher initial reduction potentials, while the bagasse-derived carbon-supported antimony single-atom catalyst obtained by pyrolysis temperature of 1100℃ has an initial reduction potential similar to that of commercial Pt / C and produces a larger limiting diffusion current, reflecting its excellent electrocatalytic performance in oxygen reduction reaction.

[0046] Figure 6 is with Figure 5 The linear voltammetric scanning curves of the sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate obtained by linear voltammetric scanning method under different electrode speeds. It can be seen from the figure that the initial reduction potential of the sample at different speeds is constant, but with the increase of speed, the limiting diffusion current is also increasing. The number of electron transfers when the oxygen molecule undergoes reduction reaction on the surface of the catalyst is 4, indicating that oxygen is fully reduced to OH- on its surface. These results show that the sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate obtained at 1100°C has extremely excellent electrocatalytic performance.

[0047] Figure 7 The catalytic stability and methanol resistance of bagasse-derived carbon-supported single-atom antimony catalyst and Pt / C activated by antimony triacetate at 0.7 V are compared. Figure 7 It can be seen in (a) that after 8 hours of operation, the current of the single-atom antimony catalyst supported on bagasse-derived carbon activated by antimony triacetate only decayed by about 6%, which is significantly lower than Pt / C (decayed by 28.5%) under the same conditions. During the operation of the single-atom antimony catalyst supported on bagasse-derived carbon activated by antimony triacetate, the addition of methanol has almost no effect on the catalytic current on its surface, while the catalytic current on Pt / C changes dramatically and becomes negative, indicating that the methanol electro-oxidation reaction on its surface dominates. These results show that the single-atom antimony catalyst supported on bagasse-derived carbon activated by antimony triacetate not only has extremely excellent electrocatalytic performance, but also has significantly improved stability and catalytic selectivity.

[0048] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0049] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a single-atom catalyst based on biomass-derived carbon, characterized in that: The raw materials include bagasse and antimony triacetate, and the preparation process mainly includes the following steps: (1) Weighing bagasse, soaking and washing with distilled water, draining, soaking in dilute nitric acid for 12 hours, filtering the bagasse, repeatedly washing the bagasse with distilled water until neutral and air-drying, weighing an appropriate amount of the air-dried bagasse, putting it into a high-pressure reactor, adding an appropriate amount of distilled water, placing it in an electric heating blast drying oven at 190° C. for 12 hours, then taking it out, washing it, and then placing it in a vacuum drying oven at 80° C. overnight to obtain a black powder; (2) the black powder obtained in step (1) is fully ground and mixed with an appropriate amount of antimony triacetate, and the resulting mixture is placed in a tube furnace under a nitrogen atmosphere and heated to 800° C. for 1 hour, then heated to 1100° C. for 2 hours, then cooled to 800° C. for 1 hour, and finally cooled to room temperature to obtain a black powder; (3) The black powder obtained in step (2) was taken out and added into 0.1 M hydrochloric acid, and reacted for 24 hours under stirring. Then, the powder was filtered and washed with distilled water until neutral, and placed in a vacuum oven at 80° C. overnight to obtain a sugarcane bagasse-derived carbon-supported single-atom antimony catalyst activated by antimony triacetate.

2. The method for preparing a single-atom catalyst based on biomass-derived carbon according to claim 1, characterized in that: The dilute nitric acid in step (1) is nitric acid: distilled water = 1:6.

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