阅读说明：本技术 一种原位生长在碳布上的铬掺杂磷化钴纳米棒阵列的制备方法 (Preparation method of chromium-doped cobalt phosphide nanorod array grown on carbon cloth in situ ) 是由 庄仲滨 张立鹏 张俊涛 于 2020-11-20 设计创作，主要内容包括：本发明的目的在于提供一种原位生长在碳布上的铬掺杂磷化钴纳米棒阵列的制备方法,具体步骤包括：先将碳布在硝酸中氧化以增强其亲水性,然后采用水热法在碳布上原位生长一层前驱体Cr-xCo-(1-x)(OH)F/CC,最后通过高温气相磷化法将生长在碳布上的前驱体转变为铬掺杂磷化钴Cr-xCo-(1-x)(OH)F/CC。该制备工艺操作简单、易于控制、成本低廉、可用于大规模生产,采用该方法制备的原位生长在碳布上的铬掺杂磷化钴纳米棒阵列分布均匀、排列紧密、棒状颗粒尺寸达到纳米级且粒径均一,铬掺杂降低氢吸附自由能的同时保留了CoP晶型,能够高效、持续、稳定地催化析氢反应的进行。(The invention aims to provide a preparation method of a chromium-doped cobalt phosphide nanorod array grown on carbon cloth in situ, which comprises the following specific steps: firstly, the carbon cloth is oxidized in nitric acid to enhance the hydrophilicity, and then a layer of precursor Cr is grown on the carbon cloth in situ by adopting a hydrothermal method x Co 1‑x (OH) F/CC, finally by high temperatureGas phase phosphorization method for converting precursor grown on carbon cloth into chromium-doped cobalt phosphide Cr x Co 1‑x (OH) F/CC. The preparation process is simple to operate, easy to control and low in cost, and can be used for large-scale production, the chromium-doped cobalt phosphide nanorod arrays grown on the carbon cloth in situ prepared by the method are uniformly distributed and closely arranged, the size of rod-shaped particles reaches the nanometer level and the particle size is uniform, the CoP crystal form is reserved while the hydrogen adsorption free energy is reduced by chromium doping, and the hydrogen evolution reaction can be efficiently, continuously and stably catalyzed.)

1. A preparation method of a chromium-doped cobalt phosphide nanorod array grown on carbon cloth in situ is characterized by comprising the following steps:

soaking the cut carbon cloth in a nitric acid solution, heating in an oil bath, stopping heating, cooling to room temperature, taking out the carbon cloth, sequentially performing ultrasonic treatment in acetone, ultrapure water and ethanol, taking out the carbon cloth subjected to ultrasonic treatment, and drying in an oven to obtain clean, dry and hydrophilicity-enhanced carbon cloth;

dissolving cobalt nitrate hexahydrate, chromium nitrate nonahydrate, urea and ammonium fluoride in certain mass in ultrapure water, and stirring to obtain a clear and transparent solution;

step (03) transferring the clear and transparent solution obtained in the step (02) into an inner liner of a polytetrafluoroethylene reaction kettle, vertically placing a piece of clean, dry and hydrophilicity-enhanced carbon cloth obtained in the step (01), covering the carbon cloth with a cover, placing the carbon cloth into a steel pressure jacket, assembling the high-pressure reaction kettle, placing the high-pressure reaction kettle into an oven, and heating the high-pressure reaction kettle for a period of time at a certain temperature;

and (04) stopping heating, cooling to room temperature, taking out the carbon cloth, washing with ultrapure water, and drying in an oven to obtain a precursor Cr growing on the carbon cloth in situ_xCo_1-x(OH)F/CC；

Step (05) a porcelain boat filled with sodium hypophosphite is arranged at one side of an air inlet of the tube furnace, and precursor Cr obtained in step (04) and growing on the carbon cloth in situ is filled_xCo_1-xPlacing ceramic boats of (OH) F/CC on one side of an air outlet, closely adjacent two ceramic boats in the middle of a tube furnace, exhausting air in the tube by using protective gas, setting a certain heating rate and a certain phosphating temperature, heating for 2 hours, cooling to room temperature under flowing protective gas after heating is finished, and obtaining the chromium-doped cobalt phosphide nanorod array Cr growing on carbon cloth in situ_xCo_1-xP/CC。

2. The method for preparing the chromium-doped cobalt phosphide nanorod array grown on the carbon cloth in situ according to claim 1, wherein the certain mass of the cobalt nitrate hexahydrate in the step (02) is selected from 0.4g to 1.2 g.

3. The method for preparing the chromium-doped cobalt phosphide nanorod array grown on the carbon cloth in situ according to claim 1, wherein the certain mass of the chromium nitrate nonahydrate in the step (02) is selected from 0.01g to 0.4 g.

4. The method for preparing the chromium-doped cobalt phosphide nanorod array grown on the carbon cloth in situ according to claim 1, wherein the certain mass of urea in the step (02) is selected from 0.5g to 1.2 g.

5. The method for preparing the chromium-doped cobalt phosphide nanorod array grown on the carbon cloth in situ according to claim 1, wherein the mass of the ammonium fluoride in the step (02) is selected from 0.1g to 0.5 g.

6. The method for preparing the chromium-doped cobalt phosphide nanorod array grown on the carbon cloth in situ according to claim 1, wherein the certain temperature of the oven in the step (03) is selected from 110 ℃ to 140 ℃.

7. The method for preparing the chromium-doped cobalt phosphide nanorod array grown on the carbon cloth in situ according to claim 1, wherein the heating period in the step (03) is selected from 5h to 10 h.

8. The method for preparing the chromium-doped cobalt phosphide nanorod array grown on the carbon cloth in situ according to claim 1, wherein the temperature rise rate in the step (05) is selected from 10 ℃/min to 20 ℃/min.

9. The method for preparing the chromium-doped cobalt phosphide nanorod array grown on the carbon cloth in situ according to claim 1, wherein the certain phosphating temperature in the step (05) is selected from 300 ℃ to 400 ℃.

10. The method for preparing the chromium-doped cobalt phosphide nanorod array grown on the carbon cloth in situ according to claim 1, wherein the chromium-doped cobalt phosphide particles in the step (05) are rod-shaped and have a diameter of 120 nm-200 nm, and the nanorods coat the carbon fibers to grow and present an array structure which is tightly and uniformly arranged.

Technical Field

The invention belongs to the technical field of micro-nano material preparation, and particularly relates to preparation of a chromium-doped cobalt phosphide nanorod array growing on carbon cloth in situ.

Background

The traditional energy structure mainly based on fossil fuel experiences dual crises of resource exhaustion and environmental pollution, and the two challenges of solving the energy problem and the environmental problem are urgently needed in human development, so people are forced to develop efficient, clean and sustainable green energy. Hydrogen energy is expected to replace fossil fuels as a clean energy source with high energy density, wide sources, convenient storage, and combustion products of water only. Among various hydrogen production methods, the electrocatalytic water cracking hydrogen production has the advantages of wide raw material source, various energy utilization forms and the like, and gradually becomes a hot spot of current hydrogen production research.

At present, the platinum-based catalyst has the highest efficiency in the cathode catalyst for water electrolysis, but the characteristics of rare platinum reserves and high cost restrict the large-scale application of the platinum-based catalyst in industrial electrolytic water and limit the popularization and development of hydrogen production by water electrolysis. Therefore, the development of non-noble metal hydrogen evolution catalytic materials with high efficiency, stability and low cost becomes a research focus in the industrial process of hydrogen production by water electrolysis. The transition metal phosphide has wide attention on the electrocatalytic performance of the excellent hydrogen evolution reaction, and compared with platinum, cobalt has richer reserves, lower price and potential suitable for large-scale production, so that cobalt phosphide has wide research and application prospects. The chromium doping can reduce the hydrogen adsorption free energy so as to improve the intrinsic activity of the cobalt phosphide, and the rod-shaped cobalt phosphide particles grow on the carbon cloth in situ to obtain a regular array structure, so that more catalytic active sites are exposed while the specific surface area is increased, the catalyst is very favorable for mass transfer and gas drainage, and the high-efficiency and stable hydrogen evolution reaction catalytic performance is provided.

The traditional preparation method of cobalt phosphide comprises the following steps: low-temperature phosphorization is carried out on a cobalt-containing precursor, programmed heating reduction is carried out on cobalt phosphate, phosphorus pentachloride is used as an inorganic phosphorus source to directly phosphorize cobalt salt, inorganic phosphorus sources such as white phosphorus and the like or organic phosphorus sources such as trioctylphosphine and the like are added in the hydrothermal synthesis process, and high-energy ball milling and other methods are carried out on metal cobalt and red phosphorus. The preparation methods generally have the defects of high raw material cost, harsh reaction conditions, difficult control, incapability of obtaining nano-scale particles with uneven particle size and the like, and are not beneficial to the wide application of cobalt phosphide.

Most of cobalt phosphide obtained by the traditional preparation method is in powder form, and needs to be dissolved in a solvent and added with an ionic polymer, then the mixture is stirred and ultrasonically treated to be uniformly dispersed to prepare catalyst slurry, and finally the catalyst slurry is uniformly sprayed, blade-coated or stamped on a substrate, and after the solvent is evaporated, an electrode for electrolyzing water is prepared. The traditional electrode preparation method is influenced by factors such as the dispersion effect of cobalt phosphide particles in a solvent, the addition ratio of an ionic polymer, the uniformity of loading of the cobalt phosphide particles on an electrode and the like, the difficulty of high-performance electrode preparation is increased, the operation is complicated, the efficiency is low, and the requirement of large-scale production cannot be met.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a preparation method of a chromium-doped cobalt phosphide nanorod array grown on carbon cloth in situ_xCo_1-x(OH) F/CC, and finally, growing a precursor Cr on the carbon cloth by a high-temperature gas-phase phosphating method_xCo_1-x(OH) F/CC conversion to Cr_xCo_1-xP/CC. The required medicine is added at one time, the synthesis method is simple and easy to operate, chromium is uniformly doped into the precursor through hydrothermal reaction, and the nanoscale rod-like chromium-doped cobalt phosphide particles with uniform particle size are synthesized and grow in situ on carbon cloth to obtain the directly usable water electrolysis hydrogen production working electrode.

The invention relates to a preparation method of a chromium-doped cobalt phosphide nanorod array grown on carbon cloth in situ, which utilizes a precursor Cr grown in situ_xCo_1-x(OH) F/CC is subjected to heat treatment under flowing phosphine atmosphere generated by thermal decomposition of sodium hypophosphite to prepare chromium-doped cobalt phosphide nanorod array Cr_xCo_1-xP/CC. The method specifically comprises the following steps:

step 1: nitric acid treatment of carbon cloth to enhance its hydrophilicity

(01) Cutting the carbon cloth into a certain size, soaking the carbon cloth in a nitric acid solution with a certain concentration, and heating the carbon cloth in an oil bath for a period of time at a certain temperature.

In the step (01), the certain size of the carbon cloth is selected from (1 cm-3 cm) × (2 cm-3 cm).

In the step (01), the certain concentration of the nitric acid solution is selected from 4 mol/L-10 mol/L.

In the step (01), the certain temperature of the oil bath is selected from 70-95 ℃.

In the step (01), the heating is carried out for a certain time selected from 4 h-10 h.

(02) Stopping heating, cooling to room temperature, taking out the carbon cloth, and sequentially performing ultrasonic treatment in a certain amount of acetone, ultrapure water and ethanol for a period of time.

In the step (02), the certain amount of the acetone, the ultrapure water and the ethanol is selected from 50 mL-100 mL.

In the step (02), the certain time of the ultrasonic treatment is selected from 20mins to 50 mins.

(03) And taking out the carbon cloth subjected to ultrasonic treatment, and drying the carbon cloth in a drying oven at a certain temperature for a period of time to obtain clean, dry and hydrophilicity-enhanced carbon cloth.

In the step (03), the certain temperature of the oven is selected from 50 ℃ to 70 ℃.

In the step (03), the drying time is selected from 2 h-5 h.

Step 2: growing a layer of precursor Cr on the carbon cloth with enhanced hydrophilicity in situ_xCo_1-x(OH)F/CC

(04) Dissolving cobalt nitrate hexahydrate, chromium nitrate nonahydrate, urea and ammonium fluoride in ultrapure water with certain volume, and stirring at room temperature for a period of time to obtain a clear and transparent solution.

In the step (04), the certain mass of the cobalt nitrate hexahydrate is selected from 0.4g to 1.2 g.

In the step (04), the certain mass of the chromium nitrate nonahydrate is selected from 0.01g to 0.4 g.

In the step (04), the certain mass of the urea is 0.5 g-1.2 g.

In the step (04), the certain mass of the ammonium fluoride is selected from 0.1g to 0.5 g.

In the step (04), the certain volume of the ultrapure water is selected from 10mL to 30 mL.

In the step (04), the stirring period is selected from 1 h-2 h.

(05) Transferring the clear and transparent solution obtained in the step (04) into an inner liner of a polytetrafluoroethylene reaction kettle, vertically placing a piece of clean, dry and hydrophilicity-enhanced carbon cloth obtained in the step (03), covering the carbon cloth with a cover, placing the carbon cloth into a steel pressure jacket, and assembling the high-pressure reaction kettle.

(06) And (5) putting the high-pressure reaction kettle assembled in the step (05) into an oven, and heating for a period of time at a certain temperature.

In the step (06), the certain temperature of the oven is selected from 110 ℃ to 140 ℃.

In the step (06), the heating period is selected from 5h to 10 h.

(07) Stopping heating, cooling to room temperature, taking out the carbon cloth, rinsing with ultrapure water for several times, and drying in a drying oven at a certain temperature for a period of time to obtain the precursor Cr growing on the carbon cloth in situ_xCo_1-x(OH)F/CC。

In the step (07), the rinsing times of the ultrapure water are selected from 3 to 6.

In the step (07), the certain temperature of the oven is selected from 50 ℃ to 70 ℃.

In the step (07), the drying time is selected from 2 h-5 h.

And step 3: high-temperature gas-phase phosphating method for preparing chromium-doped cobalt phosphide nanorod array Cr growing on carbon cloth in situ_xCo_1-xP/CC

(08) Placing a porcelain boat filled with a certain mass of sodium hypophosphite at one side of an air inlet of a tube furnace, and filling the porcelain boat with the precursor Cr obtained in the step (07) and growing on the carbon cloth in situ_xCo_1-xThe porcelain boats of (OH) F/CC are arranged on one side of the air outlet of the tube furnace, and the two porcelain boats are closely adjacent to each other and are positioned in the middle of the tube furnace.

In the step (08), the certain mass of the sodium hypophosphite is 0.5 g-3 g.

(09) The air in the tube is exhausted by protective gas, then the flow is adjusted to a certain flow, and a certain heating rate and a certain phosphorization temperature are set for heating for 2 hours.

In the step (09), the certain flow rate of the protective gas is selected from 50mL/min to 100 mL/min.

In the step (09), the certain heating rate is selected from 10 ℃/min to 20 ℃/min.

In the step (09), the certain phosphating temperature is selected from 300 ℃ to 400 ℃.

(10) After heating, cooling to room temperature under flowing protective gas to obtain the chromium-doped cobalt phosphide nanorod array Cr growing on the carbon cloth in situ_xCo_1-xP/CC。

In the steps (09) to (10), the protective gas is selected from hydrogen, nitrogen, argon or helium.

The technical principle of the invention is as follows:

(1) under the temperature of 70-95 ℃, 4-10 mol/L nitric acid solution gradually oxidizes the carbon in the carbon cloth into hydroxyl and carboxyl with strong hydrophilicity, thereby increasing the hydrophilicity of the carbon cloth and being beneficial to the infiltration of the solution and the in-situ growth of the precursor on the carbon cloth.

(2) Cobalt nitrate hexahydrate as a cobalt source to provide Co in aqueous solution²⁺Chromium nitrate nonahydrate as a source of chromium to provide Cr^{3 +}At the temperature of 110-140 ℃, urea is heated to decompose to generate NH₄ ⁺And CO₃ ^2-Providing an alkaline environment to make Co²⁺And Cr³⁺Precipitation to form hydroxide, ammonium fluoride to provide F^-Meanwhile, the method also has the effects of improving the reaction rate, maintaining the reaction stability and controlling the rod-shaped morphology of the particles. The nano particles can be attached to the substrate to grow, and the carbon fibers in the carbon cloth provide good attachment sites, so that the chromium-doped cobalt phosphide precursor nanorod array Cr growing on the carbon cloth in situ is obtained_xCo_1-x(OH)F/CC。

(3) Precursor Cr_xCo_1-x(OH) F is easily decomposed by heating, sodium hypophosphite is decomposed by heating to generate phosphine gas, and Cr is heated in phosphine atmosphere_xCo_1-x(OH) F/CC, phosphorus in phosphine is combined with cobalt to form Cr_xCo_1-xP/CC。

The invention has the beneficial effects that:

(1) the hydrothermal method has the advantages of high yield, simple operation and easily controlled reaction conditions, and the precursor nanorod arrays obtained by in-situ growth on the carbon cloth have uniform grain diameter and regular arrangement; the high-temperature gas-phase phosphating method has mild conditions, complete phosphating and no damage to the array structure, and can be used for industrial large-scale batch production. The invention develops a novel preparation method of nano-scale chromium-doped cobalt phosphide by applying a hydrothermal method and a high-temperature gas-phase phosphating method to the synthesis of a chromium-doped cobalt phosphide nanorod array grown on carbon cloth in situ. In a hydrothermal method, various reactants are dissolved in water, the content of each component can be accurately controlled, the accurate mixing of molecular and ionic levels is realized, the product is slowly generated, and the precursor particles with uniform particle size and controllable morphology can be generated. In the high-temperature gas-phase phosphating process, phosphine gas generated by thermal decomposition of sodium hypophosphite and a precursor generate gas-solid phase reaction, so that the nanorod array structure is protected, precursor particles are fully contacted with the phosphine, the phosphating is thorough, and the process is provided with a tail gas absorption device, so that the air pollution is avoided.

(2) The main component of the prepared rod-shaped chromium-doped cobalt phosphide particles is Cr_xCo_1-xP, belonging to the nano-rod array material. The nanorod array structure is beneficial to increasing the specific surface area and exposing more catalytic active sites, is also very beneficial to mass transfer and gas drainage, and improves the catalytic efficiency of the hydrogen evolution reaction; the chromium is doped into the cobalt phosphide, so that the hydrogen adsorption free energy can be reduced to be closer to 0, the intrinsic activity of the catalyst is improved, and the high-efficiency and stable operation of the catalytic hydrogen evolution reaction is ensured.

Drawings

FIG. 1 is an XRD pattern of chromium-doped cobalt phosphide nanorod particles obtained in example 1 of the invention;

FIG. 2 is a TEM image of chromium-doped cobalt phosphide nanorod particles obtained in example 1 of the present invention;

FIG. 3 is an SEM image of chromium-doped cobalt phosphide nanorod arrays obtained in example 1 of the present invention;

FIG. 4 is a LSV diagram of the chromium-doped cobalt phosphide nanorod array obtained in example 1 of the present invention;

FIG. 5 is an XRD pattern of chromium-doped cobalt phosphide nanorod particles obtained in example 2 of the invention;

FIG. 6 is a TEM image of chromium-doped cobalt phosphide nanorod particles obtained in example 2 of the invention;

FIG. 7 is an SEM image of chromium-doped cobalt phosphide nanorod arrays obtained in example 2 of the invention;

FIG. 8 is a LSV diagram of the chromium-doped cobalt phosphide nanorod array obtained in example 2 of the present invention;

FIG. 9 is an XRD pattern of chromium-doped cobalt phosphide nanorod particles obtained in example 3 of the invention;

FIG. 10 is a TEM image of chromium-doped cobalt phosphide nanorod particles obtained in example 3 of the present invention;

FIG. 11 is an SEM photograph of chromium-doped cobalt phosphide nanorod arrays obtained in example 3 of the present invention;

FIG. 12 is a LSV diagram of the chromium-doped cobalt phosphide nanorod array obtained in example 3 of the invention.

Detailed Description

The invention is further explained with reference to the drawings and the embodiments.

Example 1

(01) Cutting the carbon cloth into 1-3 cm, soaking in 6mol/L nitric acid solution, and heating in oil bath at 90 deg.C for 6 hr.

(02) After stopping heating, the mixture was cooled to room temperature, and the carbon cloth was taken out and sequentially sonicated in 60mL of acetone, 80mL of ultrapure water, and 60mL of ethanol for 30 mins.

(03) And taking out the carbon cloth subjected to ultrasonic treatment, and placing the carbon cloth in a drying oven at 65 ℃ for 4h to obtain clean, dry and hydrophilicity-enhanced carbon cloth.

(04) 0.565g of Co (NO)₃)₂·6H₂O, 0.024g Cr (NO)₃)₃·9H₂O, 0.6g of CO (NH)₂)₂0.186g of NH₄F was dissolved in 20mL of ultrapure water and stirred at room temperature for 1.5h to give a light pink transparent solution.

(05) Transferring the light pink transparent solution obtained in the step (04) into a polytetrafluoroethylene reaction kettle lining, vertically placing a piece of clean, dry and hydrophilicity-enhanced carbon cloth obtained in the step (03), covering the carbon cloth with a cover, placing the carbon cloth into a steel pressure jacket, and assembling a high-pressure reaction kettle.

(06) And (5) putting the high-pressure reaction kettle assembled in the step (05) into an oven, and heating for 6 hours at 120 ℃.

(07) Stopping heating, cooling to room temperature, taking out the carbon cloth, rinsing with ultrapure water for 4 times, and drying in a 65 ℃ oven for 4 hours to obtain a light pink precursor Cr growing on the carbon cloth in situ_0.03Co_0.97(OH)F/CC。

(08) Will contain 1g of NaH₂PO₂The porcelain boat is arranged at one side of the air inlet of the tube furnace and is filled with the light pink precursor Cr obtained in the step (07)_0.03Co_0.97The porcelain boats of (OH) F/CC are arranged on one side of the air outlet of the tube furnace, and the two porcelain boats are closely adjacent to each other and are positioned in the middle of the tube furnace.

(09) With N₂After the air in the tube is exhausted, the flow rate is adjusted to 75mL/min, and the tube is heated at 300 ℃ for 2h at the heating rate of 10 ℃/min.

(10) After heating, in flowing N₂Cooling to room temperature to obtain black chromium-doped cobalt phosphide nanorod array Cr growing on carbon cloth in situ_0.03Co_0.97P/CC。

As shown in FIG. 1, the chromium-doped cobalt phosphide nanorod array Cr obtained in example 1_0.03Co_0.97P/CC well maintained the CoP crystal form.

As shown in FIG. 2, the chromium-doped cobalt phosphide nanorod array Cr obtained in example 1_0.03Co_0.97The particles in the P/CC are rod-shaped, the diameter is about 135nm, and the nanometer level is achieved.

As shown in FIG. 3, the chromium-doped cobalt phosphide nanorod array Cr obtained in example 1_0.03Co_0.97In P/CC, nano rods with uniform particle sizes coat carbon fibers to grow, and an array structure with close and uniform arrangement is presented.

As shown in FIG. 4, the chromium-doped cobalt phosphide nanorod array Cr obtained in example 1_0.03Co_0.97P/CC Linear sweep voltammetry test, 10mA cm^-2The overpotential corresponding to the current density is-41mV shows good hydrogen evolution reaction electrocatalytic performance.

Example 2

(01) Cutting the carbon cloth into 1-3 cm, soaking in 8mol/L nitric acid solution, and heating in oil bath at 85 deg.C for 6 hr.

(02) After stopping heating, the mixture was cooled to room temperature, and the carbon cloth was taken out and sequentially sonicated in 60mL of acetone, 80mL of ultrapure water, and 60mL of ethanol for 30 mins.

(03) And taking out the carbon cloth subjected to ultrasonic treatment, and placing the carbon cloth in a drying oven at 65 ℃ for 4h to obtain clean, dry and hydrophilicity-enhanced carbon cloth.

(04) 0.553g of Co (NO)₃)₂·6H₂O, 0.040g of Cr (NO)₃)₃·9H₂O, 0.6g of CO (NH)₂)₂0.186g of NH₄F was dissolved in 20mL of ultrapure water and stirred at room temperature for 1.5h to give a pink transparent solution.

(05) And (4) transferring the pink transparent solution obtained in the step (04) into an inner liner of a polytetrafluoroethylene reaction kettle, vertically placing a piece of clean, dry and hydrophilicity-enhanced carbon cloth obtained in the step (03), covering the carbon cloth with a cover, placing the carbon cloth into a steel pressure jacket, and assembling the high-pressure reaction kettle.

(06) And (5) putting the high-pressure reaction kettle assembled in the step (05) into an oven, and heating for 6 hours at 120 ℃.

(07) Stopping heating, cooling to room temperature, taking out the carbon cloth, rinsing with ultrapure water for 6 times, and drying in a 65 ℃ oven for 4h to obtain pink precursor Cr growing on the carbon cloth in situ_0.05Co_0.95(OH)F/CC。

(08) Will contain 1.2g of NaH₂PO₂The porcelain boat is arranged at one side of the air inlet of the tube furnace and is filled with pink precursor Cr obtained in the step (07)_0.05Co_0.95The porcelain boats of (OH) F/CC are arranged on one side of the air outlet of the tube furnace, and the two porcelain boats are closely adjacent to each other and are positioned in the middle of the tube furnace.

(09) With N₂After the air in the tube is exhausted, the flow rate is adjusted to 65mL/min, and the tube is heated at 300 ℃ for 2h at the heating rate of 10 ℃/min.

(10) After heating, in flowing N₂Cooling to room temperature to obtain black in situChromium-doped cobalt phosphide nanorod array Cr grown on carbon cloth_0.05Co_0.95P/CC。

As shown in FIG. 5, the chromium-doped cobalt phosphide nanorod array Cr obtained in example 2_0.05Co_0.95P/CC well maintained the CoP crystal form.

As shown in FIG. 6, the chromium-doped cobalt phosphide nanorod array Cr obtained in example 2_0.05Co_0.95The particles in the P/CC are rod-shaped, the diameter is about 140nm, and the nanometer level is achieved.

As shown in FIG. 7, the chromium-doped cobalt phosphide nanorod array Cr obtained in example 2_0.05Co_0.95In P/CC, nano rods with uniform particle sizes coat carbon fibers to grow, and an array structure with close and uniform arrangement is presented.

As shown in FIG. 8, Cr is added to the chromium-doped cobalt phosphide nanorod array obtained in example 2_0.05Co_0.95P/CC Linear sweep voltammetry test, 10mA cm^-2The overpotential corresponding to the current density of the catalyst is-38 mV, and the good hydrogen evolution reaction electrocatalytic performance is shown.

Example 3

(01) Cutting the carbon cloth into 1-3 cm, soaking in 6mol/L nitric acid solution, and heating in oil bath at 90 deg.C for 8 hr.

(02) After the heating was stopped, the mixture was cooled to room temperature, and the carbon cloth was taken out and subjected to ultrasonic treatment for 50mins in 70mL of acetone, 100mL of ultrapure water, and 70mL of ethanol in this order.

(03) And taking out the carbon cloth subjected to ultrasonic treatment, and placing the carbon cloth in a drying oven at 65 ℃ for 4h to obtain clean, dry and hydrophilicity-enhanced carbon cloth.

(04) 0.541g of Co (NO)₃)₂·6H₂O, 0.056g Cr (NO)₃)₃·9H₂O, 0.6g of CO (NH)₂)₂0.186g of NH₄F is dissolved in 20mL of ultrapure water and stirred at room temperature for 2h to obtain a dark pink transparent solution.

(05) And (4) transferring the dark pink transparent solution obtained in the step (04) into an inner liner of a polytetrafluoroethylene reaction kettle, vertically placing a piece of clean, dry and hydrophilicity-enhanced carbon cloth obtained in the step (03), covering the carbon cloth with a cover, placing the carbon cloth into a steel pressure jacket, and assembling the high-pressure reaction kettle.

(06) And (5) putting the high-pressure reaction kettle assembled in the step (05) into an oven, and heating for 7 hours at 120 ℃.

(07) Stopping heating, cooling to room temperature, taking out the carbon cloth, rinsing with ultrapure water for 5 times, and drying in a 65 ℃ oven for 4h to obtain a dark pink precursor Cr growing on the carbon cloth in situ_0.07Co_0.93(OH)F/CC。

(08) Will contain 1.1g of NaH₂PO₂The porcelain boat is arranged at one side of the air inlet of the tube furnace and is filled with the dark pink precursor Cr obtained in the step (07)_0.07Co_0.93The porcelain boats of (OH) F/CC are arranged on one side of the air outlet of the tube furnace, and the two porcelain boats are closely adjacent to each other and are positioned in the middle of the tube furnace.

(09) With N₂After the air in the tube is exhausted, the flow rate is adjusted to 75mL/min, and the tube is heated at 320 ℃ for 2h at the heating rate of 10 ℃/min.

(10) After heating, in flowing N₂Cooling to room temperature to obtain black chromium-doped cobalt phosphide nanorod array Cr growing on carbon cloth in situ_0.07Co_0.93P/CC。

As shown in FIG. 9, the chromium-doped cobalt phosphide nanorod array Cr obtained in example 3_0.07Co_0.93P/CC well maintained the CoP crystal form.

As shown in FIG. 10, the chromium-doped cobalt phosphide nanorod array Cr obtained in example 3_0.07Co_0.93The particles in the P/CC are rod-shaped, the diameter is about 180nm, and the nanometer level is achieved.

As shown in FIG. 11, the chromium-doped cobalt phosphide nanorod array Cr obtained in example 3_0.07Co_0.93In P/CC, nano rods with uniform particle sizes coat carbon fibers to grow, and an array structure with close and uniform arrangement is presented.

As shown in FIG. 12, Cr is added to the chromium-doped cobalt phosphide nanorod array obtained in example 3_0.07Co_0.93P/CC Linear sweep voltammetry test, 10mA cm^-2The overpotential corresponding to the current density of the catalyst is-47 mV, and the good hydrogen evolution reaction electrocatalytic performance is shown.