One-dimensional ladder type heterojunction cobalt titanate-tin sulfide photocatalyst as well as synthesis method and application thereof

Abstract

The invention relates to a one-dimensional ladder type heterojunction cobalt titanate-tin sulfide photocatalyst which is composed of a (012) diffraction crystal face of one-dimensional cobalt titanate fiber and a (002) diffraction crystal face of tin sulfide. The synthesis method of the one-dimensional ladder-shaped heterojunction cobalt titanate-tin sulfide photocatalyst comprises the following step: adding one-dimensional cobalt titanate fibers in a solvothermal growth process of tin sulfide, so as to obtain the one-dimensional ladder-shaped heterojunction cobalt titanate-tin sulfide photocatalyst. The one-dimensional ladder-shaped heterojunction cobalt titanate-tin sulfide photocatalyst is applied to preparation of solar fuel by catalytic reduction of CO2 under simulated sunlight. The one-dimensional ladder-shaped heterojunction cobalt titanate-tin sulfide photocatalyst has the beneficial effects that the photocatalytic performance is excellent, due to the formation of the ladder-shaped heterojunction, the photocatalyst has stronger light absorption capacity and higher carrier separation efficiency, and the yield of methane prepared by catalytic reduction of CO2 under simulated sunlight irradiation can reach 66 micromoles g <-1 > h <-1 >.

Description

Technical Field

[0001] The invention relates to the technical field of photocatalysts, and in particular to a one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst and a synthesis method and application thereof. Background Art

[0002] Environmental pollution and energy shortages seriously threaten the sustainable development of human society. Achieving carbon peak and carbon neutrality is a strategic measure to solve resource and environmental constraints and achieve sustainable development of the nation. Therefore, the development of enrichment and conversion of CO 2 technology, and the carbon-containing products obtained by catalytic conversion can be further used as energy or chemical raw materials to achieve CO 2 Inspired by the photosynthesis of green plants, researchers have developed a photocatalytic CO 2 Reduction technology uses the redox reaction induced by electrons and holes generated by semiconductor materials under light excitation to realize the conversion of solar energy into chemical energy. 2 The research and development of reduction photocatalysts is of great significance.

[0003] CO 2 The catalytic activity of the reduction photocatalyst is closely related to the diffusion, adsorption, migration of the reactants in the photocatalytic system and the desorption and transport of the products. The crystal size of the nanoparticle photocatalyst is very small and the surface energy is very high. 2 In the process, serious particle agglomeration is likely to occur, the light capture and light scattering capabilities are poor, and the active component loss is large. In addition, the nanoparticle photocatalyst cannot guarantee a stable morphology to be compounded with other photocatalysts, which is not conducive to the reuse of photocatalysts. The one-dimensional cobalt titanate fiber prepared by electrospinning can be assembled into a unique three-dimensional network, which is more conducive to the reuse of photocatalysts in the field of photocatalytic hydrogen production. It has the advantages of large specific surface area, short ion migration path, and unique one-dimensional electron transfer orbit, which can greatly improve the photocatalytic efficiency, but in the photocatalytic CO 2 Regarding the reduction to produce solar fuels, there are no public reports on one-dimensional cobalt titanate fibers. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst and a synthesis method and application, so as to solve the problems of high cost of photocatalytic production of solar fuel and low efficiency of single cobalt titanate catalyst in the above-mentioned prior art.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst is composed of a (012) diffraction crystal plane of a one-dimensional cobalt titanate fiber and a (002) diffraction crystal plane of tin sulfide.

[0007] Based on the above technical solution, the present invention can also be improved as follows.

[0008] Furthermore, tin sulfide in the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst is uniformly attached to the surface of the one-dimensional cobalt titanate fiber to form a one-dimensional heterojunction structure with close contact.

[0009] Furthermore, in the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst, tin sulfide accounts for 30% to 60% of the mass of the one-dimensional cobalt titanate fiber.

[0010] Based on the above technical solution, the present invention also provides a method for synthesizing a one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst, comprising the following steps:

[0011] One-dimensional cobalt titanate fiber is added into the solvent thermal growth process of tin sulfide to obtain a one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst.

[0012] Further, the specific synthesis steps of the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst are as follows:

[0013] S11, mixing anhydrous tin chloride and ethanol to obtain a transparent solution;

[0014] S12, adding one-dimensional cobalt titanate fiber and thioacetamide to the transparent solution obtained in S11, and subjecting the solution to solvent thermal reaction, thereby obtaining a one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst.

[0015] Furthermore, the solvent thermal reaction temperature is 120°C to 180°C, and the time is 3h to 6h.

[0016] Furthermore, the solvothermal reaction temperature was 180 °C and the time was 3 h.

[0017] Further, the synthesis steps of one-dimensional cobalt titanate fiber are:

[0018] S21, dissolving tetrabutyl titanate and cobalt acetate in methanol and acetic acid, and adding polyvinyl pyrrolidone K90 to obtain a transparent solution;

[0019] S22, adding the transparent solution obtained in S21 into the syringe, then connecting the syringe needle to a DC high voltage power supply, and adjusting the voltage and injection rate to obtain a white fiber membrane;

[0020] S23, calcining the white fiber membrane to obtain one-dimensional cobalt titanate fiber.

[0021] Furthermore, the voltage is 12 kV to 15 kV, and the injection rate is 0.9 mL / h to 1.5 mL / h.

[0022] Furthermore, the voltage was 12 kV and the injection rate was 1.2 mL / h.

[0023] Furthermore, the calcination temperature is 600° C. and the calcination time is 3 h to 5 h.

[0024] Furthermore, the calcination temperature is 600°C and the time is 4 h.

[0025] Based on the above technical solution, the present invention also provides a one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst for catalytic reduction of CO under simulated sunlight. 2 Application in the preparation of solar fuels.

[0026] The beneficial effects of the present invention are:

[0027] 1) The one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst has excellent photocatalytic performance, and due to the formation of the ladder-type heterojunction, it has stronger light absorption ability and higher carrier separation efficiency;

[0028] 2) Change SnS 2 and CoTiO 3 One-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalysts with different mass ratios can be obtained by using the ratio of

[0029] 3) It can be prepared by solvothermal method and applied to catalytic reduction of CO under simulated sunlight 2 One-dimensional ladder-shaped heterojunction cobalt titanate-tin sulfide photocatalyst for preparing solar fuel, with simple synthesis process and low cost;

[0030] 4) In-situ illumination X-ray photoelectron spectroscopy analysis proved that the composite photocatalyst is a one-dimensional ladder-type heterojunction fiber photocatalyst. The photocatalytic performance test results show that the photocatalyst catalyzes the reduction of CO under simulated sunlight. 2 The yield of methane produced can reach 66 μmol g -1 h -1 , proving that the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst has excellent activity under simulated sunlight and is an efficient, green and safe clean energy synthesis technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 CoTiO 3 、SnS 2 and series SnS 2 / CoTiO 3 X-ray diffraction pattern of the sample;

[0032] Figure 2 45% SnS 2 / CoTiO 3 Transmission electron micrograph of

[0033] Figure 3 SnS 2 and 45% SnS 2 / CoTiO 3 In-situ irradiation X-ray photoelectron spectrum of the sample;

[0034] Figure 4 For CoT iO 3 、SnS 2 and series SnS 2 / CoT 3 Photocatalytic CO 2 Reduction to CH 4 Performance graph. DETAILED DESCRIPTION

[0035] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0036] Example 1

[0037] The one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst is composed of the (012) diffraction crystal plane of the one-dimensional cobalt titanate fiber and the (002) diffraction crystal plane of tin sulfide. In the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst, tin sulfide is uniformly attached to the surface of the one-dimensional cobalt titanate fiber to form a one-dimensional heterojunction structure with close contact.

[0038] The synthesis method of one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst comprises the following specific steps:

[0039] S11, dissolve 0.35 g of anhydrous tin chloride in 60 mL of ethanol to obtain a transparent solution;

[0040] S12, add one-dimensional cobalt titanate fiber and 0.36g thioacetamide to the transparent solution, wherein the tin sulfide in the one-dimensional ladder-shaped heterojunction cobalt titanate-tin sulfide photocatalyst is 30% of the mass of the one-dimensional cobalt titanate fiber, and perform solvent thermal reaction at 120°C to 180°C for 3h to 6h, preferably: perform solvent thermal reaction at 180°C for 3h to obtain a light yellow substance, and then wash and dry the light yellow substance in turn to obtain a one-dimensional ladder-shaped heterojunction cobalt titanate-tin sulfide photocatalyst, marked as 30% SnS 2 / CoT 3 .

[0041] In this embodiment:

[0042] The synthesis steps of one-dimensional cobalt titanate fiber are as follows:

[0043] S21, dissolving 0.17 g of tetrabutyl titanate and 0.125 g of cobalt acetate in 24 mL of methanol and 1.5 mL of acetic acid, and adding 2.0 g of polyvinyl pyrrolidone K90 to obtain a transparent solution;

[0044] S22, add the transparent solution obtained in S21 into the syringe, connect the syringe needle to a DC high voltage power supply, and adjust the voltage to 12 kV to 15 kV, and the injection rate to 0.9 mL / h to 1.5 mL / h, preferably: adjust the voltage to 12 kV, and the injection rate to 1.2 mL / h, to obtain a white fiber membrane;

[0045] S23, placing the white fiber membrane in a muffle furnace, and calcining at 600° C. for 3 h to 5 h, preferably calcining at 600° C. for 4 h, to obtain one-dimensional cobalt titanate fiber.

[0046] The synthesis steps of tin sulfide are as follows:

[0047] S31, dissolve 0.35 g of anhydrous tin chloride in 60 mL of ethanol to obtain a transparent solution;

[0048] S32. Add 0.36 g of thioacetamide to the transparent solution obtained in S31, and carry out solvent thermal reaction at 180° C. for 3 h to obtain tin sulfide.

[0049] Example 2

[0050] The difference between this embodiment and embodiment 1 is that the tin sulfide in the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst is 45% of the mass of the one-dimensional cobalt titanate fiber, and the obtained product is marked as 45% SnS 2 / CoTiO 3 .

[0051] Example 3

[0052] The difference between this embodiment and embodiment 1 is that the tin sulfide in the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst is 60% of the mass of the one-dimensional cobalt titanate fiber, and the obtained product is marked as 60% SnS 2 / CoTiO 3 .

[0053] The present invention only needs to change SnS 2 and CoTiO 3 The one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst with different mass ratios can be obtained by in-situ illumination X-ray photoelectron spectroscopy analysis. It is proved that the composite photocatalyst is a one-dimensional ladder-type heterojunction fiber photocatalyst. For the above embodiments, the tin sulfide is in the form of tin sulfide nanosheets, and the cobalt titanate is in the form of one-dimensional cobalt titanate fiber. The photocatalytic performance test results show that the photocatalyst catalyzes the reduction of CO under simulated sunlight. 2The yield of methane produced can reach 66 μmol g -1 h -1 , proving that the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst has excellent activity under simulated sunlight, and the catalyst is simple to synthesize and low in cost.

[0054] from Figure 1 It can be seen that the synthesized SnS 2 and CoTiO 3 and different proportions of SnS 2 / CoTiO 3 The crystal structure and composition of the composite photocatalyst were characterized. In the XRD spectrum of the composite sample, 30% SnS 2 / CoTiO 3 、45%SnS 2 / CoTiO 3 and 60% SnS 2 / CoTiO 3 SnS can be observed in the XRD diffraction patterns 2 and CoTiO 3 The typical characteristic peaks correspond to CoTiO 3 The (012) diffraction crystal plane of SnS 2 The (002) diffraction crystal plane preliminarily confirmed that the composite photocatalyst has good crystallinity and possesses the common properties of the two monomers.

[0055] from Figure 2 It can be seen that CoTiO 3 It shows a typical mesoscopic fibrous morphology with a thin layer of nanosheets attached to the surface, which is SnS 2 ; In addition, the heterojunction interface of the two monomers intertwined can be clearly observed from the figure, confirming the formation of the heterojunction photocatalyst.

[0056] from Figure 3 It can be seen that 45% SnS 2 / CoTiO 3 The Sn 3d orbital binding energy is compared to SnS 2 The photogenerated electrons shifted to the direction of high binding energy under ultraviolet light irradiation, and shifted to the direction of low binding energy under ultraviolet light irradiation. This result shows that the photogenerated electrons shifted from CoTiO 3 To SnS 2 The SnS 2 / CoTiO 3 Interfacial electron transfer.

[0057] Combination Figure 2 and Figure 3 , it can be confirmed that SnS 2 / CoT 3 The composite photocatalyst is a ladder-type heterojunction photocatalyst.

[0058] Figure 4 CoTiO under visible light irradiation 3 、SnS 2 and series SnS 2 / CoTiO 3 Photocatalytic CO 2 Reduction to CH 4 Performance diagram, as can be seen from the figure, compared with the monomer CoTiO 3 SnS 2 , Series SnS 2 / CoT 3 The composite catalysts all showed superior photocatalytic performance over the monomers in CH 4 Yield, 45% SnS 2 / CoT 3 Samples compared to 30% SnS 2 / CoT 3 and 60% SnS 2 / CoTiO 3 With the best photocatalytic CH 4 Yield.

[0059] The present invention uses photocatalytic technology: using light as energy, CO 2 Reducing to solar fuel is an efficient, green and safe clean energy technology. It synthesizes a kind of 2 The reduced ladder heterojunction photocatalyst cobalt titanate-tin sulfide has a simple synthesis process and low cost. The one-dimensional ladder heterojunction cobalt titanate-tin sulfide photocatalyst has excellent photocatalytic performance. Due to the formation of the ladder heterojunction, it has stronger light absorption ability and higher carrier separation efficiency.

[0060] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. One-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst, characterized in that: It is composed of the (012) diffraction crystal plane of one-dimensional cobalt titanate fiber and the (002) diffraction crystal plane of tin sulfide.

2. The one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst according to claim 1, characterized in that: In the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst, tin sulfide is uniformly attached to the surface of one-dimensional cobalt titanate fibers to form a one-dimensional heterojunction structure with close contact.

3. The one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst according to claim 1, characterized in that: In the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst, tin sulfide accounts for 30% to 60% of the mass of the one-dimensional cobalt titanate fiber.

4. A method for synthesizing the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst according to any one of claims 1 to 3, characterized in that: The steps include: One-dimensional cobalt titanate fiber is added into the solvent thermal growth process of tin sulfide to obtain a one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst.

5. The synthesis method according to claim 4, characterized in that The specific synthesis steps of the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst are as follows: S11, mixing anhydrous tin chloride and ethanol to obtain a transparent solution; S12, adding one-dimensional cobalt titanate fiber and thioacetamide to the transparent solution obtained in S11, and subjecting the solution to solvent thermal reaction, thereby obtaining a one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst.

6. The synthesis method according to claim 4 or 5, characterized in that: The solvent thermal reaction temperature is 120°C to 180°C, and the time is 3h to 6h.

7. The synthesis method according to claim 4, 5 or 6, characterized in that: The synthesis steps of one-dimensional cobalt titanate fiber are: S21, dissolving tetrabutyl titanate and cobalt acetate in methanol and acetic acid, and adding polyvinyl pyrrolidone K90 to obtain a transparent solution; S22, adding the transparent solution obtained in S21 into the syringe, then connecting the syringe needle to a DC high voltage power supply, and adjusting the voltage and injection rate to obtain a white fiber membrane; S23, calcining the white fiber membrane to obtain one-dimensional cobalt titanate fiber.

8. The synthesis method according to claim 7, characterized in that The voltage is 12kV~15kV, and the injection rate is 0.9mL / h~1.5mL / h.

9. The synthesis method according to claim 7, characterized in that: The calcination temperature is 600°C and the time is 3h to 5h.

10. Use of the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst as described in any one of claims 1 to 3 or the one-dimensional ladder-type heterojunction cobalt titanate-tin sulfide photocatalyst synthesized by the synthesis method as described in any one of claims 4 to 9 in catalytic reduction of CO2 under simulated sunlight to prepare solar fuel.

Images