Bismuth tungstate / titanium carbide composite photoelectric anode material growing on carbon / carbon composite material and method

Abstract

The invention provides a bismuth tungstate / titanium carbide composite photoelectric anode material growing on a carbon / carbon composite material and a method, and the method comprises the following steps: dissolving TiC powder, Bi (NO3) 3.5 H2O and Na2WO4. 2H2O in nitric acid according to a molar ratio of (0.01-0.03): (0.01-0.03): (0.01-0.03) to obtain a precursor solution; the carbon / carbon composite material is immersed in the precursor solution and then subjected to hydrothermal treatment at 140-200 DEG C, then the obtained compound is taken out and sequentially washed and dried, and the bismuth tungstate / titanium carbide composite photoelectric anode material growing on the carbon / carbon composite material is obtained. And the prepared and synthesized Bi2WO6 / TiC-C / C photoelectric anode material shows relatively good OER performance in an alkaline solution.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoanode materials, and relates to a bismuth tungstate / titanium carbide composite photoanode material grown on a carbon / carbon composite material and a method therefor. Background Art

[0002] In the process of photocatalytic (PEC) water splitting, solar energy can be successfully converted into chemical energy, and then high-value-added hydrogen energy can be obtained. However, in this process, the oxygen evolution reaction (OER) occurring at the anode belongs to a four-electron reaction process with slow kinetics, and the added value of its product oxygen is not high, which leads to a low efficiency of the PEC water splitting system. Therefore, developing efficient photoanode materials to accelerate the rate of the OER reaction has become an urgent problem to be solved.

[0003] In the reports of photoanode photoelectrolysis of water for oxygen production, bismuth tungstate (Bi2WO6) is a commonly used material. It has a unique layered structure, which is formed by alternating stacking of [Bi2O2] 2+ layers and [WO4] 2- layers. This structure not only endows it with a certain absorption ability for visible light, but also its energy band structure is conducive to the participation of photo-generated carriers in the reaction. However, relying solely on single bismuth tungstate, its photocatalytic efficiency fails to reach the expectation, and there is a problem of a relatively high carrier recombination rate.

[0004] Currently, there are the following several ways to improve the performance of bismuth tungstate: First, by constructing a heterojunction of Bi2WO6 and other semiconductors, and using the built-in electric field formed at the interface to promote the separation of photo-generated carriers. For example, the composite of Bi2WO6 and TiO2 improves the photocatalytic activity to a certain extent. Second, the method of element doping is used to modify Bi2WO6, adjust its energy band structure, and enhance the absorption range and intensity of visible light. Third, Bi2WO6 is compounded with carbon materials, and the good conductivity of carbon materials is used to improve the transport efficiency of photo-generated carriers. For example, the composite of Bi2WO6 and graphene improves the overall performance of the material.

[0005] However, the above performance improvement measures still cannot improve the stability of the composite material. During the long-term photocatalytic reaction process, some composite materials will show structural changes or loss of active components, affecting their practical applications. For example, the photocatalytic activity significantly decreases after multiple cycles. In addition, the current methods for preparing high-performance Bi2WO6-based composite materials are often harsh in conditions and high in cost, and it is difficult to achieve large-scale industrial production. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a bismuth tungstate / titanium carbide composite photoanode material grown on a carbon / carbon composite material and a method thereof, so as to solve the problems of poor stability, harsh preparation conditions and high cost of Bi2WO6-based composite materials. The hydrothermal method is used to grow Bi2WO6 / TiC composite powder on the carbon / carbon composite material to prepare the photoanode. The preparation process is simple, easy to implement, and the prepared Bi2WO6 / TiC-C / C photoanode material exhibits good OER performance in alkaline solution.

[0007] The present invention is realized through the following technical solutions:

[0008] A method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material, comprising the following steps:

[0009] S1. Dissolve TiC powder, Bi(NO3)3·5H2O and Na2WO4·2H2O in nitric acid according to the molar ratio of (0.01-0.03):(0.01-0.03) and (0.01-0.03) to obtain a precursor solution;

[0010] S2. Immerse the carbon / carbon composite material in the precursor solution, perform hydrothermal treatment at 140-200 °C, and then take out the obtained composite and wash and dry it in sequence to obtain a bismuth tungstate / titanium carbide composite photoanode material grown on the carbon / carbon composite material.

[0011] A further improvement of the present invention lies in that

[0012] In S1, the ratio of Na2WO4·2H2O to nitric acid is (0.01-0.03) mol:(30-50) ml.

[0013] The TiC powder described in S1 is obtained according to the following process:

[0014] Mix TiO2 and carbon black evenly according to the molar ratio of (0.01-0.02):(0.2-0.3), perform calcination treatment at 1200-1400 °C, and then grind to obtain the TiC powder.

[0015] Grind the TiO2 and carbon black for 30-60 min, and then perform calcination treatment at 1200-1400 °C.

[0016] After mixing TiO2 and carbon black evenly, calcine at the above temperature for 1-4 h, and then grind.

[0017] After calcining TiO2 and carbon black at the above temperature, grind for 30-60 min to obtain TiC powder.

[0018] In S2, the carbon / carbon composite material is immersed in a precursor solution and then hydrothermally treated at 140-200° C. for 6-12 hours, and then the obtained composite is taken out and washed and dried in sequence.

[0019] The obtained composite was washed with deionized water and ethanol for 3-5 times in sequence and then dried.

[0020] The drying is carried out at 40-60° C. for 6-12 hours.

[0021] A bismuth tungstate / titanium carbide composite photoanode material obtained by any one of the above methods for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] The present invention discloses a method for growing a bismuth tungstate / titanium carbide composite photoelectric anode material on a carbon / carbon composite material by a hydrothermal method. Titanium carbide (TiC) has a sodium chloride-type cubic crystal structure, is off-white or light gray, and has a metallic luster, and has high hardness, high melting point, high chemical stability, and good electrical and thermal conductivity. By regulating the temperature of the hydrothermal method, the prepared Bi2WO6 / TiC-C / C photoelectric anode material has a strong binding force between the bismuth tungstate / titanium carbide composite powder and the matrix carbon / carbon composite material. The built-in electric field formed at the heterogeneous interface formed by bismuth tungstate and titanium carbide can strongly promote the separation of photogenerated carriers and greatly reduce the recombination of electrons and holes. The good electrical conductivity of titanium carbide allows photogenerated electrons to be quickly transmitted to the reaction site. At the same time, the heterogeneous interface changes the distribution of electron clouds on the surface of the material, optimizes the adsorption and desorption of reaction intermediates, reduces the reaction overpotential, promotes the efficient conduction of the photoelectric catalytic reaction, and greatly improves the reaction efficiency and the stability of the composite photoelectric anode material. The use of C / C substrate can effectively reduce the cost of using photoelectrocatalysts. The hydrothermal method is simple and easy to implement. It not only significantly improves the performance of photoelectrocatalytic OER, but also simplifies the operation steps and reduces costs, opening up an effective path to improve the efficiency of PEC water splitting system.

[0024] Furthermore, by controlling the hydrothermal time, the coverage and thickness of the composite powder Bi2WO6 / TiC grown on the substrate can be well regulated. The coverage and coating thickness directly affect the attachment of the active sites, so that the Bi2WO6 / TiC-C / C prepared by the present invention exhibits better photoelectrocatalytic performance in alkaline electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the XRD spectrum of TiC prepared under the conditions of Example 1 of the present invention.

[0026] Figure 2XRD pattern of Bi2WO6 / TiC prepared under the conditions of Example 1 of the present invention.

[0027] Figure 3 SEM photograph of Bi2WO6 / TiC-C / C composite material prepared under the conditions of Example 1 of the present invention.

[0028] Figure 4 J-V curve of the photoelectrocatalytic performance of Bi2WO6 / TiC-C / C composite material prepared under the conditions of Example 1 of the present invention. Detailed implementation manners

[0029] The present invention will be further described in detail below in conjunction with specific embodiments, which are explanations of the present invention rather than limitations.

[0030] A method for preparing a bismuth tungstate / titanium carbide composite photoanode material grown on a carbon / carbon composite material by a hydrothermal method according to the present invention includes the following steps:

[0031] Step 1: Weigh 0.01-0.02 mol of TiO2 as powder 1, and weigh 0.2-0.3 mol of carbon black as powder 2;

[0032] Step 2: Mix powder 1 and powder 2 and grind them in a mortar for 30 min - 1 h to obtain powder 3;

[0033] Step 3: Transfer powder 3 to a porcelain boat, place it in a tubular furnace, calcine it at 1200 - 1400 °C for 1 - 4 h, take it out and grind it for 30 min - 1 h to obtain TiC powder as powder 4;

[0034] Step 4: Weigh 0.01-0.03 mol of Bi(NO3)3·5H2O as powder 5, and weigh 0.01-0.03 mol of Na2WO4·2H2O as powder 6;

[0035] Step 5: Dissolve powder 4 (0.01-0.03 mol), powder 5 and powder 6 in 30-50 ml of nitric acid, stir at room temperature for 1-3 h, and the stirred solution is solution 1;

[0036] Step 6: Put solution 1 and the immersed C / C composite material into a 100 ml Teflon-lined autoclave, react at 140 - 200 °C for 6 - 12 h, cool to room temperature, wash it 3 - 5 times successively with deionized water and ethanol, and dry it at 40 - 60 °C for 6 - 12 h to obtain the Bi2WO6 / TiC-C / C photoanode material.

[0037] Example 1

[0038] A method for preparing a bismuth tungstate / titanium carbide composite photoanode material grown on a carbon / carbon composite material by a hydrothermal method, comprising the following steps:

[0039] Step 1, weigh 0.01 mol of TiO2 as powder 1, and weigh 0.2 mol of carbon black as powder 2;

[0040] Step 2, mix powder 1 and powder 2 and grind them in a mortar for 30 min to obtain powder 3;

[0041] Step 3, transfer powder 3 to a porcelain boat, place it in a tubular furnace, calcine it at 1400 °C for 2 h, take it out, grind it for another 30 min to obtain TiC powder, which is powder 4;

[0042] Step 4, weigh 0.01 mol of Bi(NO3)3·5H2O as powder 5, and weigh 0.01 mol of Na2WO4·2H2O as powder 6;

[0043] Step 5, dissolve 95% nitric acid in 20 ml of deionized water to obtain a dilute nitric acid solution. Dissolve powder 4 (0.01 mol), powder 5, and powder 6 in 30 ml of the dilute nitric acid solution, stir at room temperature for 1 h, and the stirred solution is solution 1;

[0044] Step 6, put solution 1 and the immersed C / C composite material into a 100 ml Teflon-lined autoclave, react at 180 °C for 6 h, cool to room temperature, wash it 3 times with deionized water and ethanol in sequence, and dry it at 60 °C for 6 h to obtain the Bi2WO6 / TiC-C / C photoanode material. The hydrothermal method can make the binding interface between Bi2WO6 and TiC closer, and at the same time can also make them grow more firmly on the C / C.

[0045] It can be seen from Figure 1 that the TiC prepared by the solid-phase sintering method has good crystallinity.

[0046] It can be seen from Figure 2 the XRD pattern that the prepared TiC powder and Bi2WO6 can be compounded by the hydrothermal method, then grown on the C / C, and the hydrothermal electrophoresis deposition does not change the phases of Bi2WO6 and TiC.

[0047] It can be seen from Figure 3 the SEM image that the powder has completely wrapped the C / C and grows relatively uniformly.

[0048] It can be seen from Figure 4From the J-V curve, it can be seen that in the 0.1 M sodium tetraborate electrolyte, since the theoretical potential of water is 1.23 V and the current of the Bi2WO6 / TiC-C / C composite material is 3.70 mA at 1.23 V, it indicates that the Bi2WO6 / TiC-C / C composite material has a strong response to light and exhibits good photoelectrocatalytic OER performance.

[0049] Example 2

[0050] A method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material by a hydrothermal method according to the present invention includes the following steps:

[0051] Step 1: Weigh 0.01 mol of TiO2 as powder 1 and weigh 0.2 mol of carbon black as powder 2;

[0052] Step 2: Mix powder 1 and powder 2 and grind them in a mortar for 30 min to obtain powder 3;

[0053] Step 3: Transfer powder 3 to a porcelain boat, place it in a tube furnace, calcine it at 1400 °C for 4 h, take it out, grind it for another 30 min to obtain TiC powder, which is powder 4;

[0054] Step 4: Weigh 0.01 mol of Bi(NO3)3·5H2O as powder 5 and weigh 0.01 mol of Na2WO4·2H2O as powder 6;

[0055] Step 5: Dissolve powder 4 (0.01 mol), powder 5 and powder 6 in 30 ml of dilute nitric acid solution, stir at room temperature for 1 h, and the stirred solution is solution 1;

[0056] Step 6: Put solution 1 and the immersed C / C composite material into a 100 ml Teflon-lined autoclave, react at 180 °C for 12 h, cool to room temperature, wash it 3 times with deionized water and ethanol in sequence, and dry it at 60 °C for 12 h to obtain the Bi2WO6 / TiC-C / C photoanode material.

[0057] Example 3

[0058] A method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material by a hydrothermal method according to the present invention includes the following steps:

[0059] Step 1: Weigh 0.01 mol of TiO2 as powder 1 and weigh 0.2 mol of carbon black as powder 2;

[0060] Step 2: Mix powder 1 and powder 2 and grind them in a mortar for 30 min to obtain powder 3;

[0061] Step 3: Transfer the powder 3 into a porcelain boat, place it in a tubular furnace, calcine it at 1200 °C for 4 h, take it out, grind it for another 30 min to obtain TiC powder, which is powder 4;

[0062] Step 4: Weigh 0.01 mol of Bi(NO3)3·5H2O, which is powder 5, and weigh 0.01 mol of Na2WO4·2H2O, which is powder 6;

[0063] Step 5: Dissolve powder 4 (0.01 mol), powder 5 and powder 6 in 30 ml of dilute nitric acid solution, stir at room temperature for 1 h, and the stirred solution is solution 1;

[0064] Step 6: Put solution 1 and the immersed C / C composite material into a 100-ml autoclave with a Teflon liner, react at 140 °C for 6 h, cool to room temperature, wash it 3 times successively with deionized water and ethanol, and then dry it at 60 °C for 12 h to obtain the Bi2WO6 / TiC-C / C photoanode material.

[0065] Example 4

[0066] A method for preparing a bismuth tungstate / titanium carbide composite photoanode material grown on a carbon / carbon composite material by a hydrothermal method according to the present invention comprises the following steps:

[0067] Step 1: Weigh 0.01 mol of TiO2, which is powder 1, and weigh 0.2 mol of carbon black, which is powder 2;

[0068] Step 2: Mix powder 1 and powder 2, grind them in a mortar for 30 min to obtain powder 3;

[0069] Step 3: Transfer powder 3 into a porcelain boat, place it in a tubular furnace, calcine it at 1400 °C for 1 h, take it out, grind it for another 30 min to obtain TiC powder, which is powder 4;

[0070] Step 4: Weigh 0.01 mol of Bi(NO3)3·5H2O, which is powder 5, and weigh 0.01 mol of Na2WO4·2H2O, which is powder 6;

[0071] Step 5: Dissolve powder 4 (0.01 mol), powder 5 and powder 6 in 30 ml of dilute nitric acid solution, stir at room temperature for 1 h, and the stirred solution is solution 1;

[0072] Step 6: Put solution 1 and the immersed C / C composite material into a 100-ml autoclave with a Teflon liner, react at 140 °C for 12 h, cool to room temperature, wash it 3 times successively with deionized water and ethanol, and then dry it at 60 °C for 12 h to obtain the Bi2WO6 / TiC-C / C photoanode material.

Claims

1. A method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material, characterized in that: The following steps are involved: S1, dissolving TiC powder, Bi(NO3)3·5H2O and Na2WO4·2H2O in nitric acid at a molar ratio of (0.01-0.03):(0.01-0.03) and (0.01-0.03) to obtain a precursor solution; S2, immersing the carbon / carbon composite material in a precursor solution and then hydrothermally treating it at 140-200° C., then taking out the obtained composite, washing and drying it in sequence, to obtain a bismuth tungstate / titanium carbide composite photoanode material grown on the carbon / carbon composite material.

2. The method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material according to claim 1, characterized in that: The ratio of Na2WO4·2H2O and nitric acid in S1 is (0.01-0.03) mol: (30-50) ml.

3. The method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material according to claim 2, characterized in that: The TiC powder described in S1 is obtained by the following process: TiO2 and carbon black are uniformly mixed in a molar ratio of (0.01-0.02):(0.2-0.3), calcined at 1200-1400°C, and then ground to obtain the TiC powder.

4. The method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material according to claim 3, characterized in that: The TiO2 and carbon black are ground for 30-60 minutes and then calcined at 1200-1400°C.

5. The method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material according to claim 3, characterized in that: After the TiO2 and carbon black are uniformly mixed, they are calcined at the temperature for 1-4 hours and then ground.

6. The method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material according to claim 3, characterized in that: TiO2 and carbon black are calcined at the temperature and then ground for 30-60 minutes to obtain TiC powder.

7. The method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material according to claim 1, characterized in that: In S2, the carbon / carbon composite material is immersed in a precursor solution and then hydrothermally treated at 140-200° C. for 6-12 hours, and then the obtained composite is taken out and washed and dried in sequence.

8. The method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material according to claim 1, characterized in that: The obtained composite was washed with deionized water and ethanol for 3-5 times in sequence and then dried.

9. The method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material according to claim 1, characterized in that: The drying is carried out at 40-60° C. for 6-12 hours.

10. A bismuth tungstate / titanium carbide composite photoanode material obtained by the method for growing a bismuth tungstate / titanium carbide composite photoanode material on a carbon / carbon composite material as described in any one of claims 1 to 9.

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