BiVO4 / tiC composite photocatalyst, preparation method and application thereof

Abstract

The application discloses a BiVO4 / TiC composite photoelectrocatalyst and a preparation method and application thereof, and the preparation method comprises the following steps: grinding titanium dioxide and carbon black powder to fully mix, then transferring the mixture to a white porcelain boat, calcining the mixture under an argon (Ar) atmosphere at 1400-1600 DEG C for 2-6 hours, grinding the mixture after the completion to obtain black TiC powder; using a low-temperature water bath method to dissolve bismuth nitrate pentahydrate in HNO3 solution, and dissolving NH4VO3 in NaOH solution at the same time, stirring to obtain a precursor solution; placing the precursor in a water bath at 60-100 DEG C for 6-10 hours, then adding the TiC powder; heating to 80-120 DEG C, continuously heating for 2-4 hours, then separating the product, washing, drying and grinding to obtain the required BiVO4 / TiC composite photoelectrocatalyst; the BiVO4 / TiC composite photoelectrocatalyst can enhance the efficient separation and transmission of photo-generated charges, improve the utilization rate of sunlight, and thus improve the oxygen evolution efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of functional materials, and relates to a photoelectrocatalytic material, in particular to a BiVO4 / TiC composite photoelectrocatalyst as well as a preparation method and application thereof. BACKGROUND

[0002] Due to economic development and resource shortage and other problems, people urgently need to develop new renewable energy to solve the current energy shortage problem. Photoelectrochemical (PEC) water splitting is considered to be one of the most potential strategies for solving environmental and energy problems in future human society. Under the irradiation of sunlight, the photoelectrode of a semiconductor generates photo-generated electrons and holes to produce hydrogen and oxygen from water splitting, respectively. In order to withstand the oxidation condition and maintain long-term stability in aqueous solution, oxide semiconductors (such as TiO2, ZnO, BiVO4 and WO3) have become the first choice of photoelectrode candidates. Among these materials, BiVO4 has attracted great attention as a photoanode for photoelectrochemical water splitting due to its suitable energy band structure and excellent semiconductor performance. The monoclinic phase of BiVO4 is an n-type semiconductor, and the valence band is mainly composed of the 6s orbital of Bi and the 2p orbital of O. The band gap energy of this material is between 2.4-2.5eV, so it is suitable for absorbing sunlight. Therefore, BiVO4 is an ideal photoanode, and it can produce oxygen at a low bias voltage compared with many other metal oxides. However, the short hole migration distance and weak electron migration ability of BiVO4 affect the photocatalytic efficiency.

[0003] Transition metal carbides (TMCs) are composed of non-noble transition metals, and since 1973, they have been known for their "Pt-like behavior". Titanium carbide is a typical transition metal carbide, and it is a very promising material due to its high resistance to acids and bases, and at the same time, it has a high melting point, high hardness, excellent elastic modulus, good electrical conductivity, low density and other advantages, which has attracted a large number of scholars to explore the low-cost and high-activity synthesis method of titanium carbide. However, the number of active sites on the surface of TiC is limited, and the charge transfer efficiency is low, which limits its electrocatalytic performance. SUMMARY

[0004] In view of the deficiencies in the prior art, the purpose of the present application is to provide a BiVO4 / TiC composite photoelectrocatalyst, a preparation method and application thereof, which can reduce charge recombination, broaden the light absorption range, improve the photoelectric conversion efficiency and oxygen evolution efficiency, and the preparation process is simple, the conditions are easy to control, and the cost is low.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A preparation method of a BiVO4 / TiC composite photoelectrocatalyst, comprising the following steps:

[0007] Step one, the titanium dioxide and carbon black powder are put into a mortar according to the mass ratio (0.5-2):(1-3), and after grinding and mixing, they are transferred to a white porcelain boat and placed in a muffle furnace, and then the temperature is raised to 1400-1600 DEG C at a heating rate of 5-15 DEG C / min under an argon Ar atmosphere, and then the furnace is naturally cooled to room temperature after calcination for 2-6 h, and then the sample is ground, and then black powder A, i.e. TiC powder, can be obtained;

[0008] Step two, 0.1-2 mmol of bismuth nitrate pentahydrate is dissolved in 50-100 mL of 0.5 mol / L HNO3 solution, and 0.1-2 mmol of NH4VO3 is dissolved in 50-100 mL of 1.0 mol / L NaOH solution, and then the two solutions are mixed under vigorous stirring to form a yellow solution, and then the solution is stirred under a magnetic stirrer for 1 h to obtain precursor A;

[0009] Step three, the precursor A is transferred to a water bath, and the water bath is set to 60-100 DEG C, and then 0.1-1 g of TiC powder is added after heat preservation for 6-10 h, and then the water bath is heated to 80-120 DEG C again, and then the heating is continued for 2-4 h, and then the reacted solution is centrifuged to remove the supernatant to obtain a precipitate, and then the precipitate is washed, dried and ground to obtain the required BiVO4 / TiC composite photoelectric catalyst.

[0010] Preferably, the grinding in step one and step three is grinding the sample in a mortar for 30-90 min.

[0011] Preferably, the centrifugation in step three is centrifugation at 8000-12000 r / min for 5-15 min.

[0012] Preferably, the washing in step three is alternating washing 3-5 times with deionized water and anhydrous ethanol.

[0013] Preferably, the drying in step three is drying the product in a vacuum drying oven at 80 DEG C for 8-16 h.

[0014] The application also protects a BiVO4 / TiC composite photoelectric catalyst prepared by the above method and its application as a photoanode in the process of photoelectric catalytic water decomposition.

[0015] Compared with the prior art, the application has the following technical effects:

[0016] The application firstly prepares TiC with small size and large specific surface area by sintering method, and then prepares BiVO4 powder with high purity and good crystallinity by low-temperature water bath method, the TiC has good conductivity, can promote the separation and transmission of photo-generated charges, reduce charge recombination, improve photoelectric conversion efficiency, and can enhance the stability of the composite material, the BiVO4 has good absorption capacity for visible light, which is helpful to improve the utilization efficiency of solar energy, the combination of the two can form a heterostructure to enhance the efficient separation and transmission of photo-generated charges, improve the utilization rate of sunlight, so as to realize the improvement of oxygen evolution efficiency;

[0017] The preparation process of the application is simple, the reaction conditions are mild and controllable, the production cost is low, and the industrial production is easy. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The X-ray diffraction analysis diagram of BiVO4 / TiC prepared in Example 2;

[0019] Figure 2 The scanning electron microscope diagram of the BiVO4 / TiC photoelectrocatalyst prepared in Example 2 under 2um;

[0020] Figure 3 The oxygen evolution performance diagram of BiVO4 / TiC prepared in Example 2 and pure TiC in a solution with pH of 9.5. DETAILED DESCRIPTION

[0021] The specific content of the application will be further explained and described in combination with the following examples. The reagents, methods and equipment used in the application are conventional reagents, methods and equipment in the technical field. Unless otherwise specified, the test method in the following examples is usually carried out according to the conventional experimental conditions. Unless otherwise specified, the reagents and raw materials used in the application can be obtained by market.

[0022] Example 1:

[0023] This embodiment gives a preparation method of BiVO4 / TiC composite photoelectrocatalyst, which comprises the following steps:

[0024] Step one, the titanium dioxide and carbon black powder are put into a mortar according to the mass ratio of 0.5:1, ground for 30min to mix thoroughly, then transferred to a white porcelain boat and placed in a muffle furnace, heated to 1400℃ at a heating rate of 5℃ / min under argon Ar atmosphere, calcined for 2h, then naturally cooled to room temperature in the furnace, and then the sample is ground for 30min to obtain black powder A, which is TiC powder;

[0025] Step two, 0.1 mmol of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) is dissolved in 50 mL of HNO3 solution with a concentration of 0.5 mol / L, and 0.1 mmol of NH4VO3 is dissolved in 50 mL of NaOH solution with a concentration of 1.0 mol / L, the two solutions are mixed under vigorous stirring to form a yellow solution, and then the solution is placed under a magnetic stirrer for 1 h to obtain precursor A;

[0026] Step three, transfer precursor A to a water bath, set the water bath to 60℃, and after 6h of incubation, add 0.1g of TiC powder; after the water bath is heated to 80℃ for the second time, continue heating for 2h, then pour the reacted solution into a centrifuge tube, centrifuge at 8000r / min for 5min, remove the supernatant, and obtain the precipitate, wash it with deionized water and anhydrous ethanol alternately for three times, put the product into a vacuum drying oven at 80℃ for 8h, take it out and grind for 30min to make it uniform, and then the desired BiVO4 / TiC composite photocatalyst is obtained;

[0027] The chi660e type device is used to test the photoelectric catalytic effect of the BiVO4 / TiC composite photocatalyst.

[0028] Example 2:

[0029] Step one, titanium dioxide and carbon black powder are placed in a mortar in a mass ratio of 1:2, ground for 60min to mix thoroughly, then transferred to a white porcelain boat and placed in a muffle furnace, heated to 1500℃ at a heating rate of 10℃ / min under an argon Ar atmosphere, calcined for 4h, and then naturally cooled to room temperature, the sample is taken out and ground for 60min to obtain black powder A, which is TiC powder;

[0030] Step two, 1 mmol of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) is dissolved in 80 mL of HNO3 solution with a concentration of 0.5 mol / L, and 1 mmol of NH4VO3 is dissolved in 80 mL of NaOH solution with a concentration of 1.0 mol / L, the two solutions are mixed under vigorous stirring to form a yellow solution, and then the solution is placed under a magnetic stirrer for 1 h to obtain precursor A;

[0031] Step three, transfer precursor A to a water bath, set the water bath to 80℃, after 8h, add 0.5g TiC powder; after the second time the water bath is heated to 100℃, continue heating for 3h, then pour the reacted solution into a centrifuge tube, centrifuge at 10000r / min for 10min, remove the supernatant, and obtain the precipitate, wash with deionized water and anhydrous ethanol for three times, put the product into a vacuum drying oven at 80℃ for 12h, take out and grind for 60min to uniformity, and then obtain the desired BiVO4 / TiC composite photocatalyst;

[0032] The chi660e model device is used to test the photoelectric catalytic effect of the BiVO4 / TiC composite photocatalyst.

[0033] Figure 1 The X-ray diffraction analysis chart of BiVO4 / TiC prepared in Example 2 is shown in the figure, where the abscissa is the 2θ angle and the ordinate is the diffraction peak intensity, and the composite phase powder can accurately correspond to BiVO4 PDF#14-0688 card and TiC PDF#32-1383 card, indicating that the BiVO4 powder and TiC powder are successfully compounded;

[0034] Figure 2 The scanning electron microscope image of BiVO4 / TiC photocatalyst prepared in Example 2 at 2um is shown in the figure, from which it can be seen that the sheet-shaped BiVO4 is attached with block TiC, which shows that BiVO4 and TiC are successfully compounded;

[0035] Figure 3 The oxygen evolution performance diagram of BiVO4 / TiC prepared in Example 2 and pure phase TiC in a solution with pH of 9.5 is shown in the figure, from which it can be seen that the pure phase TiC photocatalyst shows a current density of 0.68mA / cm 2 at 1.23V, while the BiVO4 / TiC composite photocatalyst shows a current density of 1.57mA / cm 2 at 1.23V, which is 2.3 times higher than that of the pure phase TiC photocatalyst.

[0036] Example 3:

[0037] Step one, put titanium dioxide and carbon black powder into a mortar according to the mass ratio of 2:3, grind for 90min to mix thoroughly, then transfer to a white porcelain boat and place in a muffle furnace, heat to 1600℃ at a heating rate of 15℃ / min under argon Ar atmosphere, calcine for 2h, then naturally cool to room temperature, take out the sample and grind for 90min, and then obtain black powder A, which is TiC powder;

[0038] Step two, 2mmol of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) was dissolved in 100mL of HNO3 solution with a concentration of 0.5mol / L, while 2mmol of NH4VO3 was dissolved in 100mL of NaOH solution with a concentration of 1.0mol / L, the two solutions were mixed under vigorous stirring to form a yellow solution, and then the solution was placed under a magnetic stirrer for 1h to obtain precursor solution A;

[0039] Step three, precursor A was transferred to a water bath, the water bath was set to 100℃, and 1g of TiC powder was added after 8h of incubation; the water bath was heated to 120℃ for the second time, and then the reaction solution was poured into a centrifuge tube and centrifuged at 12000r / min for 5min. After removing the supernatant, the precipitate was obtained, and then the product was placed in a vacuum drying oven at 80℃ for 16h. After grinding for 90min, the BiVO4 / TiC composite photocatalyst was obtained.

[0040] The chi660e type device was used to test the photoelectric catalytic effect of the BiVO4 / TiC composite photocatalyst.

[0041] Example 4:

[0042] Step one, titanium dioxide and carbon black powder were placed in a mortar in a mass ratio of 0.5:3, and ground for 90min to mix thoroughly, then transferred to a white porcelain boat and placed in a muffle furnace, and heated to 1400℃ at a heating rate of 15℃ / min under an argon Ar atmosphere for 6h, then naturally cooled to room temperature, and then the sample was ground for 90min to obtain black powder A, which was TiC powder;

[0043] Step two, 0.5mmol of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) was dissolved in 100mL of HNO3 solution with a concentration of 0.5mol / L, while 1mmol of NH4VO3 was dissolved in 100mL of NaOH solution with a concentration of 1.0mol / L, the two solutions were mixed under vigorous stirring to form a yellow solution, and then the solution was placed under a magnetic stirrer for 1h to obtain precursor solution A;

[0044] Step three, transfer precursor A to a water bath, set the water bath to 60℃, add 1g TiC powder after 10h of incubation; reheat the water bath to 120℃, continue heating for 4h, then pour the reacted solution into a centrifuge tube, centrifuge at 8000r / min for 15min, remove the supernatant, and obtain the precipitate, wash with deionized water and anhydrous ethanol alternately for three times, put the product into a vacuum drying oven at 80℃ for 16h, take out and grind for 90min to uniformity, and then obtain the desired BiVO4 / TiC composite photocatalyst;

[0045] The chi660e model device is used to test the photoelectric catalytic effect of the BiVO4 / TiC composite photocatalyst.

[0046] Example 5:

[0047] Step one, put titanium dioxide and carbon black powder into a mortar according to the mass ratio of 1:1, grind for 90min to mix thoroughly, transfer to a white porcelain boat, and place in a muffle furnace, heat to 1600℃ at a heating rate of 15℃ / min under argon Ar atmosphere, calcine for 2h, and then naturally cool to room temperature, take out the sample and grind for 90min, and then obtain black powder A, which is TiC powder;

[0048] Step two, dissolve 2mmol of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) in 100mL of 0.5mol / L HNO3 solution, and dissolve 1.5mmol of NH4VO3 in 100mL of 1.0mol / L NaOH solution, mix the two solutions under vigorous stirring to form a yellow solution, then place the solution under a magnetic stirrer and stir for 1h to obtain precursor A;

[0049] Step three, transfer precursor A to a water bath, set the water bath to 80℃, add 0.8g TiC powder after 8h of incubation; reheat the water bath to 120℃, continue heating for 3h, then pour the reacted solution into a centrifuge tube, centrifuge at 1000r / min for 10min, remove the supernatant, and obtain the precipitate, wash with deionized water and anhydrous ethanol alternately for five times, put the product into a vacuum drying oven at 80℃ for 16h, take out and grind for 90min to uniformity, and then obtain the desired BiVO4 / TiC composite photocatalyst;

[0050] The chi660e model device is used to test the photoelectric catalytic effect of the BiVO4 / TiC composite photocatalyst.

[0051] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; the inferences or replacements made by those skilled in the art without departing from the concept of the present application are within the protection scope of the present application.

Claims

1. A preparation method of a BiVO4 / TiC composite photocatalyst, characterized in that, Comprising the following steps: Step one, the titanium dioxide and carbon black powder are placed in a mortar in a mass ratio of (0.5-2):(1-3), ground to mix thoroughly, transferred to a white porcelain boat, and placed in a muffle furnace, heated to 1400-1600 ℃ at a heating rate of 5-15 ℃ / min under an argon Ar atmosphere, calcined for 2-6 h, and then naturally cooled to room temperature in the furnace. The sample is ground to obtain black powder A, which is TiC powder; Step two, 1-2 mmol of bismuth nitrate pentahydrate is dissolved in 80-100 mL of 0.5 mol / L HNO3 solution, and 1-2 mmol of NH4VO3 is dissolved in 80-100 mL of 1.0 mol / L NaOH solution. The two solutions are mixed under vigorous stirring to form a yellow solution, and then the solution is stirred in a magnetic stirrer for 1 h to obtain precursor A; Step three, the precursor A is transferred to a water bath, the water bath is set to 60-100 ℃, and 0.5-1 g of TiC powder is added after 6-10 h of incubation. The water bath is heated to 80-120 ℃ for the second time, and then heated for 2-4 h. The reacted solution is centrifuged to remove the supernatant, and then washed, dried, and ground to obtain the desired BiVO4 / TiC composite photocatalyst.

2. The method for preparing BiVO4 / TiC composite photocatalyst according to claim 1, characterized in that, The grinding in step one and step three is to grind the sample in a mortar for 30-90 min.

3. The method for preparing BiVO4 / TiC composite photocatalyst according to claim 1, characterized in that, The centrifugation in step three is at 8000-12000 r / min for 5-15 min.

4. The method for preparing BiVO4 / TiC composite photocatalyst according to claim 1, characterized in that, The washing in step three is to alternate between deionized water and anhydrous ethanol for 3-5 times.

5. The method for preparing BiVO4 / TiC composite photocatalyst according to claim 1, characterized in that, The drying in step three is to place the product in a vacuum drying oven at 80 ℃ for 8-16 h.

6. A BiVO4 / TiC composite photocatalyst prepared by the method of any one of claims 1-5.

7. Use of the BiVO4 / TiC composite photocatalyst of claim 6 as a photoanode in the process of photocatalytic water splitting.

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