A ZnCo2S4 / NiO composite photocatalyst and a preparation method and application thereof

Abstract

The application belongs to the technical field of photocatalytic hydrogen production, and particularly relates to a ZnCo2S4 / NiO composite photocatalyst as well as a preparation method and application thereof. The ZnCo2S4 nanoparticles are uniformly deposited or grown on the surface of the NiO nanosheet through a calcination-hydrothermal method, so as to improve the aggregation of the ZnCo2S4 nanoparticles, further increase the specific surface area of the catalyst, and provide more reaction sites. Meanwhile, the ZnCo2S4 and the NiO nanosheet form a Z-type heterostructure, reduce the recombination of the photo-generated charges of the ZnCo2S4, form an internal electric field, accelerate the transfer of the photo-generated charges, inhibit the recombination rate of the photo-generated electrons and holes, and improve the hydrogen evolution efficiency of the photocatalyst. The composite catalyst has good photocatalytic hydrogen production performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photocatalytic hydrogen production, and particularly relates to a ZnCo2S4 / NiO composite photocatalyst and a preparation method and application thereof. BACKGROUND

[0002] Hydrogen is considered to be an ideal green fuel in the future, and is a potential non-carbon-based energy source that can replace fossil fuels. Since the reaction product is water, there is no carbon dioxide emission. However, due to the high cost of traditional hydrogen production methods, environmentally friendly renewable hydrogen is still not popular. The photocatalytic water splitting technology for hydrogen production using semiconductor catalysts provides a very promising method for realizing clean, low-cost and environmentally friendly hydrogen production by solar energy.

[0003] Zinc-based photocatalysts have been widely used due to their low cost, high utilization rate, suitable band structure and chemical / thermal stability. Cobalt is more stable in the environment than Cd, Ni or Cu, and is much cheaper than transition metals. Therefore, it is very attractive to introduce cobalt as a photocatalyst. ZnCo2S4 is a typical double-metal sulfide, which has attracted increasing attention. ZnCo2S4 has a suitable band gap as well as a conduction band, a valence band position, good light absorption and excellent electrical conductivity. However, ZnCo2S4 is a small-sized nanoparticle, and the photocatalytic hydrogen evolution ability of ZnCo2S4 is poor, and ZnCo2S4 is also prone to aggregation, which affects the separation and transfer of charges, resulting in further weakening of the photocatalytic hydrogen evolution performance. SUMMARY

[0004] In view of the deficiencies in the prior art, the application aims to provide a ZnCo2S4 / NiO composite photocatalyst and a preparation method and application thereof. In the application, NiO is first prepared by a hydrothermal-calcination method, and then ZnCo2S4 is grown on the surface of NiO by a solvothermal method to form a ZnCo2S4 / NiO composite photocatalyst, so as to improve the efficiency of ZnCo2S4 photocatalytic hydrogen production.

[0005] The application provides a preparation method of a ZnCo2S4 / NiO composite photocatalyst, which comprises the following steps:

[0006] S1: dispersing a nickel source in a solvent, adding ammonia water to adjust the pH value, stirring sufficiently, then performing a hydrothermal reaction, followed by centrifugal cleaning and drying, and finally calcining the dried solid powder to obtain NiO nanosheets.

[0007] Further, the nickel source is nickel chloride dihydrate, the solvent is deionized water, and the dosage ratio of the nickel source to the deionized water is (8.0-8.9) mmol:30 mL.

[0008] Further, the ratio of the amount of the nickel source to the amount of the deionized water is 8.0 mmoL:30 mL.

[0009] Further, the pH value is 9-11.

[0010] Further, the stirring time is 10-60 min, and the stirring rate is 600-900 rpm.

[0011] Further, the hydrothermal reaction temperature is 150-180 ℃, and the hydrothermal reaction time is 5-8 h.

[0012] Further, the centrifugal washing solvent is deionized water and / or ethanol, and the centrifugal speed is 8000-9000 rpm.

[0013] Further, the calcination temperature is 200-400 ℃, the temperature rising rate is 2-5 ℃ / min, and the calcination time is 1.5-3 h.

[0014] S2: The NiO nanosheet is mixed with a solvent to prepare a suspension, a zinc source, a cobalt source, and a sulfur source are added to the suspension, a basic substance is used to adjust the pH value, and then the suspension is stirred sufficiently and subjected to a hydrothermal reaction, followed by centrifugal washing and drying to obtain a ZnCo2S4 / NiO composite catalyst.

[0015] Further, the solvent is deionized water.

[0016] Further, the nickel source is nickel chloride dihydrate, the zinc source is zinc acetate dihydrate, the cobalt source is cobalt nitrate hexahydrate, and the sulfur source is thioacetamide.

[0017] Further, the molar ratio of the NiO nanosheet to the zinc source, the cobalt source, and the sulfur source is (1.0-1.7):(0.5-2):(1-4):(4-16).

[0018] Further, the molar ratio of the NiO nanosheet to the zinc source, the cobalt source, and the sulfur source is 1.5:0.5:1:4.

[0019] Further, the basic substance used to adjust the pH value is sodium hydroxide, and the pH value is 9-11.

[0020] Further, the pH value is 9.

[0021] Further, the stirring time is 0.5-2 h, and the stirring rate is 600 rpm.

[0022] Further, the centrifugal washing solvent is deionized water and / or ethanol, and the centrifugal speed is 10000 rpm.

[0023] Further, the hydrothermal reaction temperature is 180-200 ℃, and the hydrothermal reaction time is 10-12 h.

[0024] The application of the ZnCo2S4 / NiO composite photocatalyst prepared by the method in photocatalytic hydrogen production: the catalyst and the sacrificial agent are uniformly mixed and then added into a reaction kettle, which is placed in a nitrogen-filled closed reactor, and the reaction is carried out under the irradiation of simulated sunlight and at a temperature of 5-8 DEG C; wherein the sacrificial agent is composed of 0.35 mol / L sodium sulfide solution and 0.25 mol / L sodium sulfite solution.

[0025] The application has the following advantages:

[0026] 1. The preparation method of the application can make ZnCo2S4 nanoparticles more suitable and uniformly deposited or grown on the surface of NiO nanosheets under the induction of photo-generated electrons and holes, so as to improve the aggregation, further increase the specific surface area of the catalyst, provide more reaction sites, reduce the recombination of photo-generated charges of ZnCo2S4, form an internal electric field, and accelerate the transfer of photo-generated charges.

[0027] 2. The ZnCo2S4 / NiO composite catalyst with Z-type heterojunction formed by ZnCo2S4 and NiO can accelerate the directional transfer of photo-generated charges and reduce the recombination of photo-generated carriers, so as to improve the photocatalytic property of the material; compared with ZnCo2S4 and NiO, the photocatalytic performance of ZnCo2S4 / NiO is significantly improved, and the hydrogen evolution efficiency reaches 1496.46 μmol g -1 h -1 , which is 24.6 times and 8.4 times that of ZnCo2S4 and NiO respectively.

[0028] 3. The preparation method of the application can realize significant performance improvement only by adding a small amount of non-noble metal oxide semiconductor, which greatly reduces the preparation cost of the composite catalyst.

[0029] 4. The preparation method of the application has a relatively low reaction temperature, reduces energy consumption, makes the experimental process safer, and has simple raw materials, small energy consumption and simple operation; the synthesized composite material has good photocatalytic hydrogen production performance. DETAILED DESCRIPTION

[0030] Figure 1 Fig. 1 is an XRD spectrum of ZnCo2S4, NiO and ZnCo2S4 / NiO composite photocatalyst prepared in Example 1, (b), (c), (d) are SEM images of ZnCo2S4, NiO and ZnCo2S4 / NiO composite photocatalyst prepared in Example 1 respectively.

[0031] Figure 2 Fig. 2 is an electron paramagnetic resonance (EPR) spectrum of ZnCo2S4 / NiO composite photocatalyst prepared in Example 3.

[0032] Figure 3 Figure 6 is a graph of photocatalytic hydrogen production for ZnCo2S4, NiO, and ZnCo2S4 / NiO composite photocatalysts prepared in Examples 1-4.

[0033] Figure 4 Figure 7 is a graph of photocatalytic hydrogen production for ZnCo2S4, NiO, and ZnCo2S4 / NiO composite photocatalysts prepared in Examples 1-4.

[0034] Figure 5 Figure 8 is a graph of photocatalytic hydrogen production rate for ZnCo2S4 / NiO composite photocatalysts prepared in Example 3, Examples 5-7.

[0035] Figure 6 Figure 9 is a graph of photocatalytic hydrogen production for ZnCo2S4 / NiO composite photocatalysts prepared in Example 3, Examples 8-9.

[0036] Figure 7 Figure 10 is a graph of photocatalytic hydrogen production cycling for ZnCo2S4 / NiO composite photocatalysts prepared in Example 3.

[0037] Figure 8 Figure 11 is a graph of photocatalytic hydrogen production for CuCo2S4, and catalysts prepared in Example 3, Example 10. DETAILED DESCRIPTION

[0038] The following examples are further illustrations of the present application and are not intended to limit the present application in any way. The present application encompasses all alternatives, modifications and variations of the examples disclosed herein, as readily will become apparent to those of ordinary skill in the art upon reading the present disclosure.

[0039] Example 1

[0040] (1) Preparation of NiO nanosheets

[0041] A nickel source was dispersed in deionized water, and the amount ratio of the nickel source to the deionized water was 8 mmoL:30 mL. Ammonia was added to adjust the pH value to 11, and after sufficient stirring, a hydrothermal reaction was performed at 160°C for 6 h, followed by centrifugal washing, drying, and heating at a rate of 5°C / min to 300°C, and calcining for 2 h, to prepare the NiO nanosheets.

[0042] (2) Preparation of ZnCo2S4 / NiO composite photocatalysts

[0043] Take 1.0 mmol of the above prepared NiO nanosheet to be dissolved in 50 mL of deionized water to make a suspension, the molar ratio of NiO to zinc source, cobalt source and sulfur source is 1:0.5:1:4, use sodium hydroxide solution to adjust the pH value to 9, fully stir at 600 rpm for 1.5 h, then react at 180℃ for 12 h, then centrifugal washing, drying, to prepare ZnCo2S4 / NiO composite photocatalyst, recorded as ZCS / NiO-1.

[0044] Example 2

[0045] (1) Preparation of NiO nanosheet

[0046] The nickel source is dispersed in deionized water, the dosage ratio of nickel source to deionized water is 8 mmol:30 mL. Add ammonia water to adjust the pH value to 11, after fully stirring, carry out hydrothermal reaction at 160℃ for 6h, then centrifugal washing, drying, heating to 300℃ at a rate of 5℃ / min, calcining for 2h, to prepare NiO nanosheet.

[0047] (2) Preparation of ZnCo2S4 / NiO composite photocatalyst

[0048] Take 1.3 mmol of the above prepared NiO nanosheet to be dissolved in 50 mL of deionized water to make a suspension, the molar ratio of NiO to zinc source, cobalt source and sulfur source is 1.3:0.5:1:4, use sodium hydroxide solution to adjust the pH value to 9, fully stir at 600 rpm for 1.5 h, then react at 180℃ for 12 h, then centrifugal washing, drying, to prepare ZnCo2S4 / NiO composite photocatalyst, recorded as ZCS / NiO-2.

[0049] Example 3

[0050] (1) Preparation of NiO nanosheet

[0051] The nickel source is dispersed in deionized water, the dosage ratio of nickel source to deionized water is 8 mmol:30 mL. Add ammonia water to adjust the pH value to 11, after fully stirring, carry out hydrothermal reaction at 160℃ for 6h, then centrifugal washing, drying, heating to 300℃ at a rate of 5℃ / min, calcining for 2h, to prepare NiO nanosheet.

[0052] (2) Preparation of ZnCo2S4 / NiO composite photocatalyst

[0053] Take 1.5 mmol of the above prepared NiO nanosheet to be dissolved in 50 mL of deionized water to make a suspension, the molar ratio of NiO to zinc source, cobalt source and sulfur source is 1.5:0.5:1:4, use sodium hydroxide solution to adjust the pH value to 9, fully stir at 600 rpm for 1.5 h, then react at 180℃ for 12 h, then centrifugal washing, drying, to prepare ZnCo2S4 / NiO composite photocatalyst, recorded as ZCS / NiO-3.

[0054] Example 4

[0055] (1) Preparation of NiO nanosheet

[0056] The nickel source is dispersed in deionized water, the dosage ratio of nickel source to deionized water is 8 mmol:30 mL, ammonia water is added to adjust the pH value to 11, after fully stirring, hydrothermal reaction is carried out at 160℃ for 6 h, then centrifugal washing, drying, heating to 300℃ at a rate of 5℃ / min, calcining for 2 h, to prepare NiO nanosheet.

[0057] (2) Preparation of ZnCo2S4 / NiO composite photocatalyst

[0058] Take 1.7 mmol of the above prepared NiO nanosheet to be dissolved in 50 mL of deionized water to make a suspension, the molar ratio of NiO to zinc source, cobalt source and sulfur source is 1.7:0.5:1:4, use sodium hydroxide solution to adjust the pH value to 9, fully stir at 600 rpm for 1.5 h, then react at 180℃ for 12 h, then centrifugal washing, drying, to prepare ZnCo2S4 / NiO composite catalyst, recorded as ZCS / NiO-4.

[0059] Example 5

[0060] (1) Preparation of NiO nanosheet

[0061] The nickel source is dispersed in deionized water, the dosage ratio of nickel source to deionized water is 8.3 mmol:30 mL. Ammonia water is added to adjust the pH value to 11, after fully stirring, hydrothermal reaction is carried out at 160℃ for 6 h, then centrifugal washing, drying, heating to 300℃ at a rate of 5℃ / min, calcining for 2 h, to prepare NiO nanosheet.

[0062] (2) Preparation of ZnCo2S4 / NiO composite photocatalyst

[0063] Take 1.5 mmol of the above prepared NiO nanosheet to be dissolved in 50 mL of deionized water to make a suspension, the molar ratio of NiO, zinc source, cobalt source and sulfur source is 1.5:0.5:1:4, use sodium hydroxide solution to adjust the pH value to 9, fully stir at 600 rpm for 1.5 h, then react at 180℃ for 12 h, then centrifugal washing, drying, to prepare ZnCo2S4 composite photocatalyst, recorded as ZCS / NiO-5.

[0064] Example 6

[0065] (1) Preparation of NiO nanosheet

[0066] The nickel source is dispersed in deionized water, the dosage ratio of nickel source to deionized water is 8.6 mmol:30 mL. Add ammonia water to adjust the pH value to 11, after fully stirring, carry out hydrothermal reaction at 160℃ for 6h, then centrifugal washing, drying, heating to 300℃ at a rate of 5℃ / min, calcining for 2h, to prepare NiO nanosheet.

[0067] (2) Preparation of ZnCo2S4 / NiO composite photocatalyst

[0068] Take 1.5 mmol of the above prepared NiO nanosheet to be dissolved in 50 mL of deionized water to make a suspension, the molar ratio of NiO, zinc source, cobalt source and sulfur source is 1.5:0.5:1:4, use sodium hydroxide solution to adjust the pH value to 9, fully stir at 600 rpm for 1.5 h, then react at 180℃ for 12 h, then centrifugal washing, drying, to prepare ZnCo2S4 / NiO composite photocatalyst, recorded as ZCS / NiO-6.

[0069] Example 7

[0070] (1) Preparation of NiO nanosheet

[0071] The nickel source is dispersed in deionized water, the dosage ratio of nickel source to deionized water is 8.9 mmol:30 mL. Add ammonia water to adjust the pH value to 11, after fully stirring, carry out hydrothermal reaction at 160℃ for 6h, then centrifugal washing, drying, heating to 300℃ at a rate of 5℃ / min, calcining for 2h, to prepare NiO nanosheet.

[0072] (2) Preparation of ZnCo2S4 / NiO composite photocatalyst

[0073] Take 1.5 mmol of the above prepared NiO nanosheet to be dissolved in 50 mL of deionized water to make a suspension, the molar ratio of NiO, zinc source, cobalt source and sulfur source is 1.5:0.5:1:4, use sodium hydroxide solution to adjust the pH value to 9, fully stir at 600 rpm for 1.5 h, then react at 180℃ for 12 h, then centrifugal washing, drying, to prepare ZnCo2S4 / NiO composite photocatalyst, recorded as ZCS / NiO-7.

[0074] Example 8

[0075] (1) Preparation of NiO nanosheet

[0076] The nickel source is dispersed in deionized water, the amount ratio of nickel source and deionized water is 8.0 mmol:30 mL. Add ammonia to adjust the pH value to 11, after fully stirring, carry out hydrothermal reaction at 160℃ for 6h, then centrifugal washing, drying, to prepare NiO nanosheet.

[0077] (2) Preparation of ZnCo2S4 / NiO composite photocatalyst

[0078] Take 1.5 mmol of the above prepared NiO nanosheet to be dissolved in 50 mL of deionized water to make a suspension, the molar ratio of NiO, zinc source, cobalt source and sulfur source is 1.5:0.5:1:4, use sodium hydroxide solution to adjust the pH value to 9, fully stir at 600 rpm for 1.5 h, then react at 180℃ for 12 h, then centrifugal washing, drying, to prepare ZnCo2S4 / NiO composite photocatalyst, recorded as ZCS / NiO-7.

[0079] Example 9

[0080] (1) Preparation of NiO nanosheet

[0081] The nickel source is dispersed in deionized water, the amount ratio of nickel source and deionized water is 8.0 mmol:30 mL. Add ammonia to adjust the pH value to 11, after fully stirring, carry out hydrothermal reaction at 160℃ for 6h, then centrifugal washing, drying, to prepare NiO nanosheet.

[0082] (2) Preparation of ZnCo2S4 / NiO composite photocatalyst

[0083] Take 1.5 mmol of the above prepared NiO nanosheet to be dissolved in 50 mL of deionized water to make a suspension, the molar ratio of NiO to zinc source, cobalt source and sulfur source is 1.5:0.5:1:4, use sodium hydroxide solution to adjust the pH value to 11, fully stir at 600 rpm for 1.5 h, then react at 180℃ for 12 h, then centrifugal washing, drying, to prepare ZnCo2S4 / NiO composite photocatalyst, recorded as ZCS / NiO-9.

[0084] Example 10

[0085] (1) Preparation of NiO nanosheet

[0086] The nickel source is dispersed in deionized water, the amount ratio of nickel source to deionized water is 8.0 mmol:30 mL. Add ammonia water to adjust the pH value to 11, after fully stirring, carry out hydrothermal reaction at 160℃ for 6h, then centrifugal washing, drying, and heating to 300℃ at a rate of 5℃ / min, calcining for 2h, to prepare NiO nanosheet.

[0087] (2) Preparation of CuCo2S4 / NiO composite photocatalyst

[0088] Take 1.5 mmol of the above prepared NiO nanosheet to be dissolved in 50 mL of deionized water to make a suspension, the molar ratio of NiO to copper source, cobalt source and sulfur source is 1:2:1:4, use sodium hydroxide solution to adjust the pH value to 9, fully stir at 600 rpm for 1.5 h, then react at 180℃ for 12 h, then centrifugal washing, drying, to prepare CuCo2S4 / NiO composite photocatalyst.

[0089] Example 11

[0090] Dissolve 1 mmol of zinc acetate dihydrate, 2 mmol of cobalt nitrate hexahydrate and 8 mmol of thioacetamide in 100 ml of deionized water. The solution is respectively treated by ultrasonic and stirring for 30 min. Then, add sodium hydroxide to the solution to adjust the pH value to 9, continue to stir for 1.5 h until the solution turns black. Finally, hydrothermal at 180℃ for 12 hours, washed with ethanol and deionized water, and dried at 60℃, to obtain ZnCo2S4(ZCS) nanoparticles.

[0091] Example 12 Application of composite photocatalyst in photocatalytic hydrogen production

[0092] The reaction was carried out in a closed vacuum instrument, and the temperature of the reaction kettle was controlled at 7 DEG C by a water cooling system. 10 mg of catalyst was added to 50 ml of a sacrificial agent, a uniform suspension was obtained by ultrasonic crushing, the suspension was placed in a quartz reaction kettle, the reaction bottle containing the suspension was fixed on the reactor, and the closed reactor was filled with nitrogen. Under the irradiation of a 300 w xenon lamp, the content of H2 in the gas phase was detected by gas chromatography every 30 min; wherein the sacrificial agent was prepared by mixing 0.35 mol / L sodium sulfide solution and 0.25 mol / L sodium sulfite solution in any proportion.

[0093] Result analysis:

[0094] Figure 1 (a) shows the XRD spectra of ZnCo2S4, NiO and ZnCo2S4 / NiO composite photocatalyst prepared in Example 1, ZnCo2S4 has four obvious characteristic peaks at 2θ = 28.6°, 33.2°, 47.6° and 56.5°, respectively, corresponding to (111), (200), (220) and (311) crystal faces of ZnCo2S4. NiO has five obvious characteristic peaks at 37.1°, 43.1°, 62.6°, 75.0° and 79.0°, respectively, corresponding to (111), (200), (220), (311) and (222) crystal faces. In addition, the characteristic peaks of ZnCo2S4 and NiO can be observed in the diffraction peaks of the ZnCo2S4 / NiO composite photocatalyst, which proves that the ZnCo2S4 / NiO composite photocatalyst is successfully synthesized in the embodiment of the application.

[0095] Figure 1 (b), (c), (d) show the morphology of ZnCo2S4, NiO and ZnCo2S4 / NiO composite photocatalyst by SEM. Figure 1 In (b), ZnCo2S4 presents an irregular nanoparticle structure, the single particle size is about 20-50 nm, and it is aggregated together. Figure 1 In (c), the NiO nanosheet prepared by the hydrothermal method presents a sheet structure with an edge length of about 200 nm. Figure 1 In (d), ZnCo2S4 is deposited on the surface of the NiO nanosheet in the form of nanoparticles, which indicates that the ZnCo2S4 / NiO composite photocatalyst is successfully synthesized in the embodiment of the application.

[0096] Figure 2The electronic paramagnetic resonance (EPR) figure of the embodiment example 3 is shown, and the main active free radicals in the oxidation half-reaction process and the photocatalytic process are explored by electronic paramagnetic resonance (EPR). No signal peak of the active substance is detected under dark conditions. After visible light irradiation for 3 min, the DMPO-·OH signal of ZnCo2S4 / NiO appears. The redox potential of ·OH / H2O is about 1.6-1.9 V (vs NHE), and the VB of ZnCo2S4 and NiO is 1.0 and 2.73 V (vs NHE), respectively. These results show that ·OH is the main active substance in the photocatalytic process, and the successful detection of ·OH free radicals verifies the Z-scheme charge transfer mechanism.

[0097] The application further provides the composite photocatalyst for use in the field of photocatalytic hydrogen production, for photocatalytic decomposition of water to produce hydrogen.

[0098] The hydrogen production performance of ZnCo2S4, CuCo2S4, NiO and the photocatalysts prepared in the embodiment examples 1-11 under xenon lamp irradiation is studied in the embodiment example 12.

[0099] From Figure 3 , 4 The photocatalytic hydrogen production performance of the composite photocatalysts prepared in the embodiment examples 1-4 is shown, and it can be seen from the figure that the hydrogen production performance is significantly improved after the ZnCo2S4 (ZCS) nanoparticles and the NiO nanosheet are compounded, and the hydrogen production performance of the catalyst is optimal under the condition that the molar ratio of the NiO nanosheet to the zinc source, the cobalt source and the sulfur source is 1.3:0.5:1:4, which is 1496.46 μmol g -1 h -1 , which is 24.6 times of the ZCS nanoparticles and 8.4 times of the NiO nanosheet.

[0100] Figure 5 The photocatalytic hydrogen production effect of the catalysts prepared in the embodiment examples 3, 5, 6 and 7 is shown, and it is indicated that the optimal dosage ratio of the nickel source to water is 8 mmol:30 mL.

[0101] Figure 6 The photocatalytic hydrogen production yield diagram of the catalysts prepared in the embodiment examples 3, 8 and 9 is shown, and the change of the pH of the reaction solution in the compounding process of ZnCo2S4 and NiO will affect the hydrogen production effect of the composite photocatalyst, and the optimal pH value of the reaction solution is 9.

[0102] Figure 7 is the hydrogen production cycle experiment result of the embodiment example 3, and in 5 cycles, the hydrogen evolution activity of the composite photocatalyst is stable and slightly reduced, which indicates that the ZCS / NiO composite photocatalyst has good stability in hydrogen production.

[0103] Figure 8is a hydrogen production effect diagram of Example 3 and Example 10. By changing the catalyst supported on the NiO nanosheet to CuCo2S4, it can be found through comparison by hydrogen production experiment that, compared with the hydrogen production activity of ZnCo2S4 / NiO, CuCo2S4 itself has hydrogen production activity, but after the CuCo2S4 is compounded with NiO, no hydrogen production activity is exhibited.

[0104] The above-mentioned ideal embodiments according to the present application are for illustration, and through the above-mentioned description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. A method for preparing a ZnCo2S4 / NiO composite photocatalyst, characterized in that, The ZnCo2S4 / NiO composite photocatalyst is formed by growing ZnCo2S4 nanoparticles on the surface of NiO nanosheets and is a z-scheme; the preparation method of the ZnCo2S4 / NiO composite photocatalyst comprises the following steps: mixing NiO nanosheets with deionized water to prepare a suspension, adding a zinc source, a cobalt source and a sulfur source, the molar ratio of the NiO nanosheets, the zinc source, the cobalt source and the sulfur source being 1.5:0.5:1:4, adding an alkaline substance to adjust the pH value to 9, fully stirring, then reacting at 180-200 DEG C for 10-12 h, and then centrifuging, washing, drying to prepare the ZnCo2S4 / NiO composite catalyst.

2. The method for preparing the ZnCo2S4 / NiO composite photocatalyst according to claim 1, characterized in that, The NiO nanosheets are prepared by the following method: After mixing a nickel source and deionized water in a ratio of (8.0-8.9) mmol:30 mL, adding ammonia water to adjust the pH value to 9-11, fully stirring, then reacting at 150-180 DEG C for 5-8 h, and then centrifuging, washing, drying and finally calcining, the NiO nanosheets are prepared.

3. The method for preparing the ZnCo2S4 / NiO composite photocatalyst according to claim 2, characterized in that, The nickel source is nickel chloride dihydrate; the zinc source is zinc acetate dihydrate; the cobalt source is cobalt nitrate hexahydrate; and the sulfur source is thioacetamide.

4. The method for preparing the ZnCo2S4 / NiO composite photocatalyst according to claim 1, characterized in that, The alkaline substance is sodium hydroxide. 5.The method for preparing ZnCo2S4 / NiO composite photocatalyst according to claim 2, characterized in that, The calcination temperature is 200-400 DEG C, the heating rate is 2-5 DEG C / min, and the calcination time is 1.5-3 h.

6. The application of the ZnCo2S4 / NiO composite photocatalyst in photocatalytic hydrogen production according to claim 1.

7. Use according to claim 6, characterized in that, The method comprises the following steps: uniformly mixing the catalyst and the sacrificial agent, then adding them into a reaction kettle, placing the reaction kettle in a nitrogen-filled sealed reactor, and reacting under the irradiation of simulated sunlight at a temperature of 5-8 DEG C; wherein the sacrificial agent is composed of 0.35 mol / L sodium sulfide solution and 0.25 mol / L sodium sulfite solution.

Images