Application of sulfur-vacancy-rich zinc cadmium sulfide solid solution catalyst in catalytic system for synthesizing formamide from methanol and ammonia under visible light
By introducing sulfur vacancies into the ZnCdS lattice, a sulfur-rich zinc cadmium sulfide solid solution catalyst was developed, which solved the problems of narrow spectral response, insufficient reaction rate, and low selectivity in the photocatalytic synthesis of formamide, thus achieving efficient and selective synthesis of formamide.
Patent Information
- Application Number
- CN202610011656.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-06
- Publication Date
- 2026-02-17
AI Technical Summary
Existing photocatalytic formamide synthesis technologies suffer from narrow spectral response range, insufficient reaction rate, and poor selectivity. In particular, titanium dioxide-based catalysts rely on ultraviolet light and have many side reactions, resulting in low solar energy utilization and low formamide yield.
The synthesis of formamide from methanol and ammonia under visible light was achieved using a sulfur-vacancy-rich zinc cadmium sulfide solid solution catalyst. By introducing sulfur vacancies into the ZnCdS lattice, the spectral response range was expanded, the charge separation efficiency was optimized, and the adsorption behavior of free radical intermediates was regulated to promote the CN coupling reaction.
A highly efficient synthesis of formamide under visible light was achieved, with a yield of 4.27 mmol gcat-1h-1 and a selectivity of 87.4%, surpassing the performance of existing catalysts and simplifying the preparation process for industrial production.
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Figure CN121534740A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalytic materials technology, specifically the application of sulfur-rich zinc cadmium sulfide solid solution catalyst in the photocatalytic synthesis of formamide from methanol and ammonia under visible light. Background Technology
[0002] Amides are a class of fundamental organic compounds with wide applications in pharmaceuticals, agriculture, and materials science due to their structural diversity and high stability. Among these compounds, formamide (HCONH2), as the simplest amide, is both a key precursor and an important industrial solvent, with a global annual demand exceeding 2 million tons. Currently, industrial-scale formamide production still relies on thermocatalytic processes, which utilize fossil-derived carbon monoxide (CO) and ammonia (NH3) under harsh conditions of high temperature and high pressure (313K~373K, 0.1MPa~30MPa). These processes not only consume non-renewable resources but also significantly increase greenhouse gas emissions. Therefore, there is an urgent need to develop green, efficient, and sustainable synthetic alternatives.
[0003] Semiconductor-based photocatalysis has emerged as a promising approach to advancing green synthesis. By utilizing photoexcited charge carriers, photocatalytic systems can drive thermodynamically uplifting or kinetically slow reactions under mild conditions, directly converting solar energy into chemical energy. Such processes can form critical chemical bonds, such as C-N bonds, without the use of toxic reagents or excessive energy input.
[0004] Recent groundbreaking research has demonstrated the feasibility of photocatalytic synthesis of formamide from simple and abundant raw materials. For example, Dong and colleagues developed a bismuth single-atom catalyst supported on titanium dioxide, which promoted the oxidative coupling reaction of methanol and ammonia via a radical-mediated pathway (•CH2OH and •NH2), achieving a formamide selectivity of 49.7%. Further advancing this field, Xiong et al. reported a palladium-modified titanium dioxide photocatalyst, which achieved a formamide selectivity of 3.56 mmol g / L. -1 h -1 The rate and selectivity of formamide production were high. Although some progress has been made in photocatalytic formamide synthesis technology, the field is still in its early stages of development and faces three major challenges: 1) Narrow spectral response range - existing systems (especially titanium dioxide-based catalysts) mainly rely on ultraviolet irradiation, which accounts for 7% of the solar spectrum, resulting in low solar energy utilization; 2) Insufficient reaction rate - rapid recombination of photogenerated carriers and insufficient activation of reactants jointly restrict reaction kinetics; 3) Poor selectivity - side reactions (such as methanol auto-oxidation) often dominate, significantly reducing the yield of the target product, formamide. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides the application of a sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst in the visible light photocatalytic synthesis of formamide from methanol and ammonia. This invention is the first to apply a sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst to the visible light photocatalytic synthesis of formamide from methanol and ammonia. Compared with existing formamide photocatalysts, this invention is, on the one hand, a low-cost non-precious metal catalyst, and on the other hand, achieves catalysis under visible light, overcoming the technical limitation of existing catalysts that can only catalyze under ultraviolet light. More importantly, this invention is systematically designed from three dimensions: focusing on expanding the spectral response range, utilizing visible light for photocatalysis, optimizing charge separation efficiency, and precisely controlling the adsorption behavior and reactivity of free radical intermediates, thereby promoting the formation of the target CN coupling pathway and overcoming the technical defects of existing formamide photocatalysts.
[0006] Based on the above technical objectives, the present invention adopts the following technical solution: This invention protects the application of a sulfur-vacancy-rich zinc-cadmium sulfide solid solution catalyst in a visible-light photocatalytic synthesis of formamide from methanol and ammonia. The sulfur-vacancy-rich zinc-cadmium sulfide solid solution catalyst is obtained by forming sulfur vacancies within a ZnCdS crystal lattice. Under visible-light catalysis, the sulfur-vacancy-rich zinc-cadmium sulfide solid solution catalyst is used to catalyze the synthesis of formamide from methanol and ammonia.
[0007] Preferably, the sulfur-vacancy-rich zinc cadmium sulfide solid solution catalyst exhibits a viscosity of 4.27 mmol g / L under visible light irradiation. cat -1 h -1 The formamide yield.
[0008] Preferably, the sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst exhibits 87.4% formamide selectivity under visible light irradiation.
[0009] Preferably, the sulfur-rich vacancy zinc-cadmium sulfide solid solution catalyst is prepared according to the following steps: soluble zinc salt and soluble cadmium salt are co-dispersed in water to obtain a mixed solution; a sulfur source is added to the mixed solution and mixed evenly to obtain a reaction solution; hydrazine hydrate, a reducing agent, is added to the reaction solution, and a hydrothermal reaction is carried out. During the hydrothermal reaction, ZnCdS is formed, and simultaneously, hydrazine hydrate decomposes and releases hydrogen gas, partially reducing Zn. 2+ and Cd 2+ To maintain overall charge neutrality, S reaches a lower valence state. 2- The amount of sulfur decreases accordingly, resulting in the formation of sulfur vacancies in the ZnCdS lattice, thus obtaining a sulfur-vacancy-rich zinc cadmium sulfide solid solution catalyst.
[0010] Preferably, the volume ratio of soluble zinc salt to hydrazine hydrate is 1 mmol: 1 mL to 7 mL. When the amount of hydrazine hydrate added is insufficient, it cannot create a sufficiently strong reducing environment in the synthesis system, directly leading to low sulfur vacancy construction efficiency and insufficient sulfur vacancy concentration, severely restricting its catalytic activity. Compared to insufficient addition, the problems caused by excessive hydrazine hydrate are more complex and destructive, with multifaceted harms, including sulfur vacancy supersaturation becoming recombination centers, high-density defects causing lattice structure destruction, and excessive reduction leading to the generation of harmful byproducts. Ultimately, this results in a dual decrease in catalytic activity and stability. In short, excessive strong reducing agents induce a series of uncontrollable physical and chemical changes, damaging the catalyst's structure, electronic properties, and stability at multiple levels.
[0011] Preferably, the volume ratio of the soluble zinc salt to hydrazine hydrate is 1 mmol: 5 mL.
[0012] Preferably, the hydrothermal reaction conditions are: hydrothermal reaction at 180℃~200℃ for 18h~24h.
[0013] Preferably, the molar ratio of soluble zinc salt, soluble cadmium salt and sulfur source is 1:1:1.9~2.1.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention is the first to apply a sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst to the photocatalytic synthesis of formamide from methanol and ammonia. The aforementioned background technology illustrates that existing formamide photocatalysts either have poor formamide selectivity or are precious metal catalysts that can only achieve formamide synthesis under ultraviolet light irradiation. However, this invention, by applying a sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst to the photocatalytic synthesis of formamide from methanol and ammonia, effectively improves the formamide selectivity and achieves the synthesis of formamide under natural light using non-precious metals. The results show that the formamide yield and formamide selectivity are both superior to those of precious metal catalysts.
[0015] This invention utilizes visible light-responsive ZnCdS rich in surface sulfur vacancies. v Solid solution catalysts are used for the efficient synthesis of formamide from methanol and ammonia. Sulfur vacancies, as intrinsic electronic defects, can introduce new defect energy levels into the semiconductor band structure. Their main functions are as follows: ① Trapping photogenerated electrons: Sulfur vacancies can act as effective electron traps, capturing photogenerated electrons, thereby inhibiting the rapid recombination of electron-hole pairs and extending the carrier lifetime. ② Providing active sites: The charge enrichment in the sulfur vacancy region makes it an active center for the catalytic reaction, lowering the reaction energy barrier. Furthermore, the introduced sulfur vacancies effectively promote the separation of photogenerated electron-hole pairs, which helps to improve and enhance the photocatalytic activity of sulfur-vacancy-rich zinc cadmium sulfide solid solution catalysts.
[0016] Figure 3 The results show that ZnCdS v Solid solution catalysts have strong visible light absorption capabilities; Figure 8 The results show that ZnCdS v Solid solution catalysts can also precisely regulate the adsorption behavior and reactivity of free radical intermediates, thereby promoting the formation of target CN coupling pathways.
[0017] 2. The present invention relates to a visible light-responsive ZnCdS rich in surface sulfur vacancies. v The solid solution catalyst achieved a high 4.27 mmol g / L osmosis rate under visible light irradiation. cat -1 h -1 This invention achieves a high formamide yield while maintaining a high selectivity of 87.4%, surpassing all currently reported photocatalysts for formamide synthesis. This invention photochemically converts abundant small carbon and nitrogen-containing molecules into high-value-added amide compounds, which holds significant promise for alleviating current dependence on fossil fuels.
[0018] 3. This invention utilizes a one-step hydrothermal method to prepare visible light-responsive ZnCdS rich in surface sulfur vacancies. v Solid solution catalysts are easy to prepare and suitable for large-scale industrial production.
[0019] 4. The sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst of the present invention can not only catalyze the efficient synthesis of formamide from methanol and ammonia, but also achieve photocatalytic hydrogen production during the catalytic process, thereby simultaneously obtaining formamide and hydrogen. Attached Figure Description
[0020] Figure 1 ZnCdS for Comparative Example 1 and ZnCdS for Example 3 v X-ray diffraction (XRD) pattern.
[0021] Figure 2 In Figure a), ZnCdS from Example 3 is shown. v Figure b) shows the transmission electron microscope (TEM) image of ZnCdS in Example 3. v High-resolution transmission electron microscopy (HRTEM) image.
[0022] Figure 3 ZnCdS for Comparative Example 1 and ZnCdS for Example 3 v The UV-Vis diffuse reflectance spectrum (UV-vis DRS).
[0023] Figure 4 ZnCdS for Comparative Example 1 and ZnCdS for Examples 1 to 4 v A comparison chart of photocatalytic performance.
[0024] Figure 5 ZnCdS for Comparative Example 1 and ZnCdS for Example 3 v Selectivity diagram of photocatalytic formation of formamide.
[0025] Figure 6 ZnCdS as described in Example 3 v The photocatalytic formation of formamide coupled with hydrogen production is shown in the diagram.
[0026] Figure 7 ZnCdS for Comparative Example 1 and ZnCdS for Example 3 v Transient photocurrent response diagram under visible light illumination.
[0027] Figure 8 ZnCdS for Comparative Example 1 and ZnCdS for Example 3 v Temperature-programmed desorption (TPD) graphs; wherein, (a) graph shows ZnCdS in Comparative Example 1 and ZnCdS in Example 3. v Figure (b) shows the temperature-induced descaling of methanol, and Figure (c) shows ZnCdS in Comparative Example 1 and ZnCdS in Example 3. v The attached diagram shows the process of heating and removing ammonia gas. Detailed Implementation
[0028] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below with reference to specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention. Unless otherwise specified, the experimental methods and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials described are commercially available.
[0029] The sulfur-rich vacancy zinc-cadmium sulfide solid solution catalyst of the present invention introduces hydrazine hydrate during the preparation process of conventional ZnCdS solid solution catalysts. The hydrazine hydrate decomposes and releases hydrogen gas, partially reducing Zn. 2+ and Cd 2+ To maintain overall charge neutrality, S reaches a lower valence state. 2- The amount of sulfur decreases accordingly, resulting in the formation of sulfur vacancies in the ZnCdS lattice. Based on the formation of sulfur-rich vacancies in ZnCdS, the photocatalytic synthesis of formamide from methanol and ammonia under visible light was achieved.
[0030] The technical solution of the present invention will be further studied using examples and comparative examples. The specific research methods and results are shown below: Comparative Example 1 The preparation method of zinc cadmium sulfide solid solution catalyst includes the following steps: Weigh 1 mmol of Zn(OAc)2·2H2O and 1 mmol of Cd(OAc)2·2H2O respectively, and add them together to 80 mL of deionized water. Sonicate until dissolved to obtain a mixed solution. Add 2 mmol of H2NCSNH2 to the mixed solution, sonicate until dissolved, and stir at room temperature for 1 h to obtain a reaction solution. Transfer the reaction solution to a reaction vessel and hydrothermally react at 180 °C for 24 h. After the reaction is completed, allow it to cool naturally to room temperature. Wash the obtained ZnCdS sample with deionized water and then dry it at 60 °C.
[0031] The preparation process of the sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst is similar to that of ZnCdS, except that a small amount of reducing agent H4N2·H2O needs to be added, as shown in the example: Example 1 The preparation method of sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst includes the following steps: Weigh 1 mmol of Zn(OAc)₂·2H₂O and 1 mmol of Cd(OAc)₂·2H₂O separately, and add them together to 75 mL of deionized water. Sonicate until dissolved to obtain a mixed solution. Add 2 mmol of H₂NCSNH₂ to the mixed solution, sonicate until dissolved, and stir at room temperature for 1 h to obtain a reaction solution. Add 1 mL of H₄N₂·H₂O dropwise to the reaction solution, transfer to a reaction vessel, and hydrothermally react at 180 °C for 24 h. After the reaction is complete, allow to cool naturally to room temperature to obtain the ZnCdS₂ solution. V After multiple centrifugations and washing with deionized water, the samples were dried in an oven at 60°C for 12 hours.
[0032] Example 2 The preparation steps are the same as in Example 1, except that the amount of H4N2·H2O is replaced with 3 mL instead of 1 mL.
[0033] Example 3 The preparation steps are the same as in Example 1, except that the amount of H4N2·H2O is replaced with 5 mL instead of 1 mL.
[0034] Example 4 The preparation steps are the same as in Example 1, except that the amount of H4N2·H2O is replaced with 7 mL instead of 1 mL.
[0035] Example 5 The preparation method of sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst includes the following steps: Weigh 1 mmol of Zn(OAc)₂·2H₂O and 1 mmol of Cd(OAc)₂·2H₂O separately, and add them together to 75 mL of deionized water. Sonicate until dissolved to obtain a mixed solution. Add 1.9 mmol of H₂NCSNH₂ to the mixed solution, sonicate until dissolved, and stir at room temperature for 1 h to obtain a reaction solution. Add 1 mL of H₄N₂·H₂O dropwise to the reaction solution, transfer to a reaction vessel, and hydrothermally react at 200 °C for 18 h. After the reaction is complete, allow to cool naturally to room temperature to obtain the ZnCdS₂ solution. V After multiple centrifugations and washing with deionized water, the samples were dried in an oven at 60°C for 12 hours.
[0036] Example 6 The preparation method of sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst includes the following steps: Weigh 1 mmol of Zn(OAc)₂·2H₂O and 1 mmol of Cd(OAc)₂·2H₂O separately, and add them together to 75 mL of deionized water. Sonicate until dissolved to obtain a mixed solution. Add 2.1 mmol of H₂NCSNH₂ to the mixed solution, sonicate until dissolved, and stir at room temperature for 1 h to obtain a reaction solution. Add 1 mL of H₄N₂·H₂O dropwise to the reaction solution, transfer to a reaction vessel, and hydrothermally react at 190 °C for 20 h. After the reaction is complete, allow to cool naturally to room temperature to obtain the ZnCdS₂ solution. V After multiple centrifugations and washing with deionized water, the samples were dried in an oven at 60°C for 12 hours.
[0037] Examples 1-6 of this invention all yielded sulfur-rich zinc-cadmium sulfide solid solution catalysts with excellent performance in catalyzing the synthesis of formamide from methanol and ammonia under visible light. The following studies use the sulfur-rich zinc-cadmium sulfide solid solution catalysts from Examples 1-4 as examples, and the specific research methods and results are shown below: Results and Discussion: ZnCdS solid solution was synthesized via a hydrothermal method using cadmium acetate and zinc acetate as metal sources and thiourea as a sulfur source. During the hydrothermal process, a controlled amount of hydrazine hydrate was added as a reducing agent to introduce sulfur vacancies into the ZnCdS lattice, thereby obtaining sulfur-vacancy-rich ZnCdS (labeled as ZnCdS). v During the reaction, hydrazine hydrate decomposes and releases hydrogen gas, partially reducing the Zn in the solid solution. 2+ and Cd 2+ To maintain overall charge neutrality, S reaches a lower valence state. 2- The content of sulfur decreases accordingly, leading to the formation of sulfur vacancies within the ZnCdS lattice. X-ray diffraction (XRD) pattern ( Figure 1The results showed that, compared to the standard reference spectrum of hexagonal cadmium sulfide (JCPDS: 41-1049), the diffraction peaks of ZnCdS shifted to higher angles; while compared to hexagonal zinc sulfide (JCPDS: 39-1363), the diffraction peaks of ZnCdS shifted to lower angles, confirming the successful formation of the ZnCdS solid solution. Furthermore, the ZnCdS in Example 3... v The diffraction peaks are slightly shifted at a higher 2θ angle relative to the original ZnCdS, indicating that the introduction of sulfur vacancies will induce lattice shrinkage.
[0038] Figure 2 Transmission electron microscopy (TEM) images show that ZnCdS in Example 3 v The sample exhibits a bulk structure with particle sizes ranging from 20 nm to 60 nm. High-resolution transmission electron microscopy (HRTEM) images clearly show lattice fringes with measured spacings of 0.336 nm and 0.315 nm, corresponding to the (002) and (102) crystal planes of hexagonal ZnCdS, respectively. ZnCdS from Example 3 v The crystal lattice fringes show wrinkles and breaks, and the disorder increases, which is attributed to the formation of sulfur vacancies in the solid solution.
[0039] Figure 3 ZnCdS for Comparative Example 1 and ZnCdS for Example 3 v The ultraviolet-visible diffuse reflectance (UV-vis DRS) spectra of ZnCdS in Comparative Example 1 and ZnCdS in Example 3 are shown in the figure. v All samples exhibited strong visible light absorption.
[0040] Evaluation of photocatalytic performance: The photocatalytic reaction was carried out in a quartz tube using a 300W xenon lamp and a focusing membrane. In typical operation, 5 mg of catalyst was dispersed in 5 mL of ammonia solution containing 1 mmol of methanol. After the reaction, the product was filtered through a PES membrane; quantitative analysis of the product was performed by nuclear magnetic resonance (NMR).
[0041] Using methanol as a model substrate, the photocatalytic performance of the catalysts synthesized in Examples 1-4 and Comparative Example 1 was evaluated. Figure 4 As shown, the formamide yield of the original ZnCdS in Comparative Example 1 was low (0.84 mmol g). cat -1 h -1 This is mainly attributed to the rapid recombination of photogenerated carriers and insufficient activation of the methanol and ammonia substrates. The introduction of sulfur vacancies in Examples 1-4 significantly improved the formamide yield; among the variants, the ZnCdS in Example 3 showed the highest yield. v It exhibited the highest efficiency, at 4.27 mmol g. cat -1 h -1 It is approximately 5.1 times that of the original ZnCdS in Comparative Example 1.
[0042] Figure 5 and Figure 6 Detection methods and Figure 4 same.
[0043] Figure 5 The results show that, compared with the original ZnCdS in Comparative Example 1, the ZnCdS in Example 3... v It achieved a formamide selectivity of 87.4%. Furthermore, it surpassed all previously reported formamide photocatalysts.
[0044] Figure 6 ZnCdS in Example 3 v Photocatalytic formamide production coupled with hydrogen production yield diagram. As shown in the figure, the ZnCdS yield in Example 3... v It can simultaneously generate formamide and hydrogen through photocatalysis, producing hydrogen while methanol and ammonia react.
[0045] The separation efficiency of semiconductor photogenerated electron-hole pairs is analyzed by testing the transient photocurrent of the sample. Figure 7 ZnCdS for Comparative Example 1 and ZnCdS for Example 3 v The transient photocurrent response under visible light illumination is shown in the figure. The illumination lamp was switched on and off at 20-second intervals. When visible light irradiated the sample, a current was instantaneously generated; when the illumination lamp was turned off, the current intensity immediately decreased to zero. Tests show that ZnCdS… v The photocurrent density of ZnCdS is much greater than that of ZnCdS, indicating that ZnCdS has abundant sulfur vacancies compared to ZnCdS. v The separation and migration efficiency of photogenerated carriers is higher.
[0046] The adsorption behavior of ammonia and methanol on the samples was further investigated using temperature-programmed desorption (TPD) analysis. Figure 8 The CH3OH-TPD diagram shows that, compared with ZnCdS, ZnCdS... v Not only does the desorption peak shift to higher temperatures in the weak adsorption region (100℃~300℃), but it also exhibits new adsorption characteristics in the medium to strong adsorption region (300℃~500℃). Furthermore, a new ammonia adsorption peak was detected in the high-temperature region of NH3-TPD. These observations indicate that ZnCdS… v The surface contains effective active sites, which enhances the adsorption of ammonia and methanol, thereby forming a local reactant-rich microenvironment that is conducive to the initiation of C−N coupling reaction.
[0047] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations that fall within the scope of the claims and their equivalents.
Claims
1. The use of a sulfur-rich, vacancy-zinc-cadmium-sulfide solid solution catalyst in a photocatalytic system for the synthesis of formamide from methanol and ammonia under visible light, characterized in that, The sulfur-vacancy-rich zinc cadmium sulfide solid solution catalyst is formed by forming sulfur vacancies in a ZnCdS crystal lattice.
2. Use according to claim 1, characterized in that, The sulfur-rich vacancy zinc cadmium sulfide solid solution catalyst has a formamide yield of 4.27 mmol g cat -1 h -1 under visible light irradiation.
3. Use according to claim 1, characterized in that, The sulfur-vacancy-rich zinc cadmium sulfide solid solution catalyst has a formamide selectivity of 87.4% under visible light irradiation.
4. Use according to claim 1, characterized in that, The application method is as follows: the sulfur-vacancy-rich zinc cadmium sulfide solid solution catalyst is mixed with a methanol and ammonia solution, and then irradiated under visible light to prepare formamide.
5. The use according to claim 1, characterized in that, The sulfur-vacancy-rich zinc cadmium sulfide solid solution catalyst is prepared according to the following steps: The soluble zinc salt and the soluble cadmium salt are dispersed in water to obtain a mixed solution, a sulfur source is added into the mixed solution and mixed uniformly to obtain a reaction liquid, a reducing agent hydrazine hydrate is added into the reaction liquid, and a hydrothermal reaction is carried out, in the process of the hydrothermal reaction, ZnCdS is formed, at the same time, the hydrazine hydrate is decomposed and hydrogen is released, and part of Zn 2+ and Cd 2+ is reduced to a lower valence state, in order to maintain the overall charge neutrality, the amount of S 2- is reduced accordingly, resulting in the formation of sulfur vacancies in the ZnCdS lattice, and a sulfur vacancy-rich zinc cadmium sulfide solid solution catalyst is obtained.
6. Use according to claim 5, characterized in that, The mass amount of the soluble zinc salt and the volume of the hydrazine hydrate are in a ratio of 1 mmol: 1 mL to 7 mL.
7. Use according to claim 5, characterized in that, The mass amount of the soluble zinc salt and the volume of the hydrazine hydrate are in a ratio of 1 mmol: 5 mL.
8. Use according to claim 5, characterized in that, The hydrothermal reaction condition is that the hydrothermal reaction is carried out at 180-200 DEG C for 18-24 hours.
9. Use according to claim 5, characterized in that, The molar ratio of the soluble zinc salt, the soluble cadmium salt and the sulfur source is 1:1:1.9-2.1.