Gallium sulfide / indium zinc sulfide composite photocatalytic material as well as preparation method and application thereof
By introducing gallium sulfide on the surface of indium zinc sulfide to form an S-type heterojunction, the problem of low photocatalytic activity of indium zinc sulfide catalytic material was solved, and the photocatalytic CO2 reduction efficiency was improved and the stability of the catalyst was improved.
Patent Information
- Application Number
- CN202510774178.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-11
- Publication Date
- 2025-09-05
AI Technical Summary
In existing photocatalytic CO2 reduction technologies, the photocatalytic activity of indium zinc sulfide catalytic materials is low and photogenerated electrons and holes recombine rapidly, resulting in low product yield and poor selectivity, and insufficient catalyst cycle stability.
The gallium sulfide/indium zinc sulfide composite photocatalytic material was prepared by a step-by-step hydrothermal method. By introducing gallium sulfide on the surface of indium zinc sulfide to form an S-type heterojunction, the built-in electric field was used to promote the separation of photogenerated electron-hole pairs, thereby improving the photocatalytic CO2 reduction efficiency.
It significantly improves the photocatalytic activity and reusability, broadens the visible light response range, simplifies the preparation process, is easy to operate, and has good catalyst stability.
Smart Images
Figure CN120586897A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of industrial catalytic material preparation, and specifically relates to a preparation method of a gallium sulfide / indium zinc sulfide composite photocatalytic material, and also relates to the gallium sulfide / indium zinc sulfide composite photocatalytic material and its application. Background Art
[0002] The resource utilization of carbon dioxide (CO2) is an important path to alleviate environmental pollution and achieve green carbon emission reduction. At present, there are a variety of carbon utilization technologies, such as CO2 polymerization and CO2 methanation. Among them, the photocatalytic CO2 reduction reaction (CO2RR) stands out with its unique advantages. This technology can use light energy to convert CO2 into clean energy or high-value-added chemicals such as CO, CH4, CH3OH, C2H4 under mild conditions, combining the dual value of carbon cycle and energy production. However, the current photocatalytic CO2RR technology still faces key challenges such as low product yield, poor selectivity, and insufficient catalyst cycle stability. Therefore, the development of new catalysts with both high catalytic activity and long-term stability has become the core direction to break through technical bottlenecks and promote the resource utilization of photocatalytic CO2.
[0003] Indium zinc sulfide (ZnIn2S4, abbreviated as ZIS) is a highly efficient catalyst for photocatalytic CO2 reduction. Its bandgap is approximately 2.0–2.4 eV, making it responsive to visible light and broadening the range of light energy utilization. Its unique band structure promotes photogenerated charge separation and reduces recombination losses. The abundant surface active sites facilitate CO2 adsorption and activation, converting CO2 into products such as CO and CH4. However, the photocatalytic CO2 reduction activity of InZnS alone is severely limited by the rapid recombination of its own photogenerated electrons and holes. Gallium (III) sulfide (Ga2S3, abbreviated as GS) is a wide-bandgap semiconductor belonging to the IIIA–VIA group. Using Ga2S3 as a cocatalyst coupled to InZnS facilitates the formation of an S-type heterojunction, thereby promoting the efficient separation of photogenerated electron-hole pairs. Compared to Z-type or II-type heterojunction structures, the S-type heterojunction forms a unique built-in electric field at the interface. This S-type heterojunction structure exploits this unique built-in electric field at the interface, thereby improving the efficiency of photocatalytic CO2 reduction. Summary of the Invention
[0004] The first object of the present invention is to provide a method for preparing a gallium sulfide / indium zinc sulfide composite photocatalytic material, which solves the problem of low photocatalytic activity of existing indium zinc sulfide catalytic materials.
[0005] The second object of the present invention is to provide a gallium sulfide / indium zinc sulfide composite photocatalytic material.
[0006] The third object of the present invention is to provide an application of a gallium sulfide / indium zinc sulfide composite photocatalytic material in the photocatalytic reduction of carbon dioxide.
[0007] The technical solution adopted by the present invention is a method for preparing a gallium sulfide / indium zinc sulfide composite photocatalytic material, which is specifically implemented according to the following steps: Step 1, preparing gallium sulfide; Step 2: Dissolve ZnCl2, InCl3·4H2O and TAA in a mixed solution of water and ethylene glycol, add citric acid to the mixed solution and mix evenly, then add gallium sulfide from step 1, transfer the mixture into a sealed reactor and place it in an electric constant temperature blast drying oven for reaction, and after the reaction is completed, cool the mixed solution to room temperature, and then centrifuge, wash and vacuum dry to obtain a gallium sulfide / indium zinc sulfide composite photocatalyst material.
[0008] The present invention is also characterized in that: In step 1, specifically: L-cysteine and gallium chloride are dissolved in water, and then the uniformly mixed solution is transferred into a reactor, sealed, and placed in an electric constant-temperature forced air drying oven for reaction. After the reaction is completed, the mixed solution is cooled to room temperature, and then centrifuged, washed, and vacuum dried to obtain gallium sulfide.
[0009] The reaction temperature is 120°C-160°C, and the reaction time is 10h-15h; the vacuum drying temperature is 60°C-100°C, and the vacuum drying time is 6h-12h.
[0010] In step 2, the molar ratio of ZnCl2, InCl3·4H2O, TAA, and citric acid is 1:2:4:1; and the amount of gallium sulfide added is 0.5%-15% of the molar amount of ZnCl2.
[0011] In step 2, the reaction temperature is 100°C-150°C, and the reaction time is 10h-20h; the vacuum drying temperature is 60°C-100°C, and the vacuum drying time is 6h-12h.
[0012] Another technical solution adopted by the present invention is that the gallium sulfide / indium zinc sulfide composite photocatalytic material is composed of an indium zinc sulfide-based catalytic material and gallium sulfide on the surface of the indium zinc sulfide-based catalytic material.
[0013] The beneficial effects of the present invention are: the gallium sulfide / indium zinc sulfide composite photocatalytic material prepared by the method of the present invention has no agglomeration, a wide visible light response range, significantly improved photocatalytic activity compared with pure indium zinc sulfide, good reusability, and a simple preparation process, mild conditions, good controllability, and easy operation. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 is the XRD pattern of ZIS, GS and 5% GS / ZIS; Figure 2a is the SEM image of ZIS; Figure 2b is the SEM image of GS; Figure 2c is the SEM image of 5% GS / ZIS; Figure 2d is a TEM image of ZIS; Figure 2e is the TEM image of GS; Figure 2f is the TEM image of 5% GS / ZIS; Figure 2g is the HR-TEM image of 5% GS / ZIS; Figure 2h It is the element mapping spectrum of 5% GS / ZIS catalyst; Figure 3a is the XPS total spectrum of ZIS, GS and 5% GS / ZIS; Figure 3b is the Zn 2p energy spectrum of ZIS and 5%GS / ZIS; Figure 3c is the In 3d energy spectrum of ZIS and 5%GS / ZIS; Figure 3d is the S 2p energy spectrum of ZIS, GS and 5%GS / ZIS; Figure 3e is the Ga 2p spectrum of GS; Figure 3f is the Ga 2p spectrum of 5% GS / ZIS; Figure 4a is the photocatalytic CO2RR performance diagram of ZIS, GS and 5%GS / ZIS; Figure 4b is the selectivity diagram of the photocatalytic products of ZIS, GS, and 5% GS / ZIS; Figure 4c This is a graph of a carbon source control experiment for generating CH4 and CO; Figure 4d is the methane yield graph of 5% GS / ZIS, ZIS and GS; Figure 4e is a graph of carbon monoxide yields of 5% GS / ZIS, ZIS, and GS; Figure 4f This is a cyclic stability test graph of 5% GS / ZIS; Figure 5a is the response diagram of 5%GS / ZIS, ZIS and GS to photocurrent under optical switching conditions; Figure 5b is the electrochemical impedance spectroscopy of 5% GS / ZIS, ZIS and GS; Figure 5cis the steady-state fluorescence peak intensity graph of 5% GS / ZIS, ZIS, and GS; Figure 5d This is a test graph of the average carrier lifetime in 5% GS / ZIS, ZIS and GS; Figure 5e is the UV-visible diffuse reflectance spectra of ZIS and GS; Figure 5f It is the Tauc diagram of ZIS and GS; Figure 5g is the VB-XPS spectrum of ZIS; Figure 5h is the band structure diagram of ZIS and GS; Figure 6a is the surface photovoltage distribution image of the ZIS; Figure 6b is the surface photovoltage distribution image of GS; Figure 6c This is the surface photovoltage distribution image of 5% GS / ZIS; Figure 7a is the XRD pattern of 5% GS / ZIS before and after reaction; Figure 7b It is the XPS graph before and after 5% GS / ZIS reaction; Figure 7c is the Zn 2p spectrum before and after the 5% GS / ZIS reaction; Figure 7d is the In 3d energy spectrum before and after the 5% GS / ZIS reaction; Figure 7e is the S 2p energy spectrum before and after the 5% GS / ZIS reaction; Figure 7f is the Ga 2p energy spectrum before and after the 5% GS / ZIS reaction; DETAILED DESCRIPTION The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0015] The gallium sulfide / indium zinc sulfide composite photocatalytic material of the present invention consists of an indium zinc sulfide-based photocatalytic material and gallium sulfide introduced onto the surface of the indium zinc sulfide-based photocatalytic material.
[0016] The preparation method of the gallium sulfide / indium zinc sulfide composite photocatalytic material of the present invention is specifically implemented according to the following steps: Step 1: dissolving L-cysteine and gallium chloride in an aqueous solution, then transferring the uniformly mixed solution into a reaction vessel, sealing the mixture, and placing it in an electrically heated constant-temperature forced air drying oven for reaction. After the reaction is completed, the mixed solution is naturally cooled to room temperature, and then centrifuged, washed, and vacuum-dried to obtain gallium sulfide; the molar ratio of L-cysteine to gallium chloride is 1:1.5; The reaction temperature is 120-160°C, and the reaction time is 10-15 hours. The vacuum drying temperature is 60-100°C, and the vacuum drying time is 6-12 hours. The reaction kettles are all stainless steel reactors lined with Teflon. Step 2, dissolving ZnCl2, InCl3·4H2O and TAA (thioacetamide) in a mixed solution of water and ethylene glycol, adding citric acid to the mixed solution and mixing evenly, then adding gallium sulfide (Ga2S3) in step 1 to obtain a mixed solution, then transferring the mixed solution into a reactor, sealing it and placing it in an electric constant temperature blast drying oven for reaction, and after the reaction is completed, naturally cooling the mixed solution to room temperature, then centrifuging, washing and vacuum drying to obtain a gallium sulfide / indium zinc sulfide composite photocatalyst material; The molar ratio of ZnCl2, InCl3·4H2O, TAA, and citric acid is 1:2:4:1; the amount of Ga2S3 added is 0.5%-15% of the molar amount of ZnCl2; The reaction temperature is 100-150°C, and the reaction time is 10-20 hours; the vacuum drying temperature is 60-100°C, and the vacuum drying time is 6-12 hours; This study uses a step-by-step hydrothermal method to prepare a gallium sulfide / indium zinc sulfide photocatalyst. By adjusting the amount of Ga2S3, the selectivity of the CO2 reduction product is improved. The matching band structures of Ga2S3 and ZnIn2S4 create an S-type heterojunction with a built-in electric field. This heterojunction effectively suppresses carrier recombination, thereby enhancing the photocatalytic CO2 reduction reaction capability.
[0017] Example 1 The preparation method of the gallium sulfide / indium zinc sulfide composite photocatalytic material of the present invention is specifically implemented according to the following steps: Step 1, L-cysteine and gallium chloride are respectively measured in a molar ratio of 1:1.5 and dissolved in an aqueous solution, and then the uniformly mixed solution is transferred into a reaction kettle, sealed, and placed in an electric constant temperature forced air drying oven for reaction. After the reaction is completed, the mixed solution is naturally cooled to room temperature, and then centrifuged, washed, and vacuum dried to obtain gallium sulfide; The reaction temperature is 120°C and the reaction time is 10 hours; the vacuum drying temperature is 60°C and the vacuum drying time is 6 hours; Step 2, respectively measuring ZnCl2, InCl3·4H2O and TAA (thioacetamide) and dissolving them in water and ethylene glycol solution, then adding citric acid to the mixed solution and mixing evenly, then adding gallium sulfide (Ga2S3) in step 1 to obtain a mixed solution, and then transferring the mixed solution into a reactor, sealing it and placing it in an electric constant temperature blast drying oven for reaction, after the reaction is completed, naturally cooling the mixed solution to room temperature, and then centrifuging, washing and vacuum drying to obtain a gallium sulfide / indium zinc sulfide composite photocatalyst material.
[0018] The molar ratio of ZnCl2, InCl3·4H2O, TAA, and citric acid is 1:2:4:1; The reaction temperature is 100°C and the reaction time is 10 hours; the vacuum drying temperature is 60°C and the vacuum drying time is 6 hours; the amount of Ga2S3 added is 3% of the molar amount of ZnCl2. Example 2 The preparation method of the gallium sulfide / indium zinc sulfide composite photocatalytic material of the present invention is specifically implemented according to the following steps: Step 1, L-cysteine and gallium chloride are measured respectively according to a molar ratio of 1:1.5, dissolved in an aqueous solution, and then the evenly mixed solution is transferred into a reactor, sealed and placed in an electric constant temperature forced air drying oven for reaction. After the reaction is completed, the mixed solution is naturally cooled to room temperature, and then centrifuged, washed and vacuum dried to obtain a gallium sulfide photocatalytic material.
[0019] The reaction temperature is 130°C and the reaction time is 12h; the vacuum drying temperature is 80°C and the vacuum drying time is 10h; Step 2: ZnCl2, InCl3·4H2O and TAA (thioacetamide) are respectively measured and dissolved in water and ethylene glycol solution, citric acid is added to the mixed solution and mixed evenly, and then gallium sulfide (Ga2S3) in step 1 is added to obtain a mixed solution, and then the mixed solution is transferred into a reactor, sealed and placed in an electric constant temperature blast drying oven for reaction, after the reaction is completed, the mixed solution is naturally cooled to room temperature, and then centrifuged, washed and vacuum dried to obtain a gallium sulfide / indium zinc sulfide composite photocatalyst material; The molar ratio of ZnCl2, InCl3·4H2O, TAA, and citric acid is 1:2:4:1; The reaction temperature was 125°C and the reaction time was 18 h. The vacuum drying temperature was 70°C and the vacuum drying time was 8 h. The amount of Ga2S3 added was 5% of the molar amount of ZnCl2. Example 3 The preparation method of the gallium sulfide / indium zinc sulfide composite photocatalytic material of the present invention is specifically implemented according to the following steps: Step 1, L-cysteine and gallium chloride are respectively measured in a molar ratio of 1:1.5 and dissolved in an aqueous solution, and then the uniformly mixed solution is transferred into a reactor, sealed and placed in an electric constant temperature forced air drying oven for reaction, and after the reaction is completed, the mixed solution is naturally cooled to room temperature, and then centrifuged, washed and vacuum dried to obtain a gallium sulfide photocatalytic material.
[0020] The reaction temperature is 160°C and the reaction time is 15h; the vacuum drying temperature is 100°C and the vacuum drying time is 12h; Step 2: ZnCl2, InCl3·4H2O and TAA (thioacetamide) are respectively measured and dissolved in water and ethylene glycol solution, citric acid is added to the mixed solution and mixed evenly, and then gallium sulfide (Ga2S3) in step 1 is added to obtain a mixed solution, and then the mixed solution is transferred into a reactor, sealed and placed in an electric constant temperature blast drying oven for reaction. After the reaction is completed, the mixed solution is naturally cooled to room temperature, and then centrifuged, washed and vacuum dried to obtain a gallium sulfide / indium zinc sulfide composite photocatalyst material.
[0021] The molar ratio of ZnCl2, InCl3·4H2O, TAA, and citric acid is 1:2:4:1; the reaction temperature is 150°C, and the reaction time is 20 hours; the vacuum drying temperature is 100°C, and the vacuum drying time is 12 hours; the amount of Ga2S3 added is 7% of the molar amount of ZnCl2.
[0022] Comparative Example 1 Step 1: ZnCl2, InCl3·4H2O and TAA (thioacetamide) are respectively measured and dissolved in water and ethylene glycol solution, and then 1 mmol of citric acid is added to the mixed solution and mixed evenly, and then the mixture is transferred into a reactor and sealed. The reactor is then placed in an electric constant temperature forced air drying oven at 125°C for 18 hours to obtain a mixed solution. After the reaction is completed, the mixed solution is naturally cooled to room temperature, and then centrifuged and washed, and then vacuum dried at 70°C for 8 hours to obtain indium zinc sulfide photocatalytic material (ZIS).
[0023] The molar ratio of ZnCl2, InCl3·4H2O, TAA, and citric acid is 1:2:4:1; Comparative Example 2 L-cysteine and gallium chloride were respectively measured and dissolved in an aqueous solution at a molar ratio of 1:1.5, and then the uniformly mixed solution was transferred into a reactor, sealed, and placed in an electric constant-temperature forced air drying oven for reaction at a temperature of 130°C for 12 hours. After the reaction was completed, the mixed solution was naturally cooled to room temperature, and then subjected to centrifugal separation, washing, and vacuum drying at a temperature of 80°C for 10 hours to obtain a gallium sulfide photocatalytic material (GS).
[0024] Example 4 Figure 1 The X-ray diffraction patterns of ZIS prepared in Comparative Example 1, GS prepared in Comparative Example 2, and 5% GS / ZIS prepared in Example 2 are shown. The crystal structure and composition of the prepared photocatalysts were characterized by X-ray diffraction (XRD). Figure 1 As shown in Figure 5, the original ZIS (PDF # 65-2023) and GS (PDF # 50-0811) have been successfully prepared. Due to the low crystallinity of GS and the relatively low GS content and high dispersion in the final product, the characteristic diffraction peaks of the GS crystal phase were not observed in the 5% GS / ZIS.
[0025] Figure 2a and Figure 2d The SEM and TEM images of ZIS show that ZIS are flower-like microspheres composed of nanosheets with a diameter of approximately 3-4 μm. Figure 2b and Figure 2e SEM and TEM images of GS, which is composed of many stacked nanosheets. Figure 2c and Figure 2f These are the SEM and TEM images of 5% GS / ZIS. It can be seen that the introduction of GS did not change the morphology of ZIS flower-like microspheres. GS was distributed around the ZIS and part of the structure was wrapped in the petals of the ZIS. Figure 2g This is the HR-TEM image of 5% GS / ZIS. The crystal plane with a crystal plane spacing of 0.321 nm is consistent with the (102) crystal plane spacing of ZIS, and the crystal plane with a crystal plane spacing of 0.191 nm is consistent with the (-424) crystal plane spacing of GS. Figure 2h is the element mapping spectrum of the catalyst. It can be seen that the presence of Zn, In, S and Ga elements indicates that GS is uniformly distributed on the surface of ZIS microspheres.
[0026] The characteristic peaks of Zn 2p, In 3d, and S 2p in 5%GS / ZIS are similar to those in ZIS, and the characteristic peaks of Ga 2p and S 2p are similar to those in GS. Figure 3a This is the overall spectrum of ZIS, GS and 5%GS / ZIS. It can be seen that all elements in ZIS are reflected in 5%GS / ZIS, while GS has low crystallinity and low content and is only partially reflected in 5%GS / ZIS. Figure 3b For example, ZIS, Zn 2p spectrum 3 / 2 and Zn 2p 1 / 2 The centers of the two peaks are located at 1022.16 eV and 1045.22 eV, respectively. Figure 3c The peaks at 445.16eV and 452.72eV are respectively assigned to In 3d 5 / 2and In 3d 3 / 2 . Figure 3d The peaks at 161.81 eV and 163.09 eV, as well as the peaks at 161.16 eV and 163.74 eV, correspond to the S 2p1 / 2 and S 2p3 / 2 of ZIS and GS, respectively. Figure 3e 、 Figure 3f The peaks at 1118.21 eV and 1145.02 eV are respectively assigned to Ga 2p in GS. 3 / 2 and Ga 2p 1 / 2 Combining the above analysis, it can be found that the characteristic peaks of Zn 2p, In 3d, and S 2p in 5%GS / ZIS shift toward the low binding energy direction relative to ZIS, while the characteristic peaks of Ga 2p and S 2p in 5%GS / ZIS shift toward the high binding energy direction relative to GS, indicating that the photogenerated electrons are transferred from ZIS to GS.
[0027] In summary, it is proved that Ga2S3 has been successfully introduced into the surface of ZnIn2S4, and finally a gallium sulfide / indium zinc sulfide composite photocatalytic material is obtained.
[0028] Example 5 The gallium sulfide / indium zinc sulfide composite photocatalytic material of the present invention can be used for photocatalytic CO2 reduction; Experimental conditions are as follows: Photocatalytic carbon dioxide reduction (CO2RR) was performed in a 100 mL quartz reactor. In a typical photocatalytic experiment, the sample was uniformly dispersed in 10 mL of a mixed solvent (TEOA:MeCN:H2O = 2:3:1, v / v). Subsequently, 10 mg of [Ru(bpy)3]Cl2·6H2O was added. Prior to illumination, the reaction mixture was evacuated to remove dissolved gases, and the photocatalytic reactor was then filled with atmospheric pressure of high-purity carbon dioxide. A 300 W xenon lamp with a UV cutoff filter (λ ≥ 420 nm) was used as the light source. The temperature was maintained at 25 °C during the reaction, and the generated products were detected and quantified by gas chromatography.
[0029] The photocatalytic CO2 reduction test was carried out in a gas-liquid-solid system of sacrificial agent. Figure 4a The results indicate that the photocatalytic CO₂RR performance of ZIS can be enhanced by adjusting the proportion of the co-catalyst GS. Comparative analysis shows that the sample with a GS content of 5% exhibits optimal activity, with a CH₄ generation rate of 27.3 μmol·g⁻¹·h⁻¹. Figure 4b The electron selectivity of the photocatalytic CO2RR products is shown, and it can be seen that the highest CH4 selectivity is 69.9% in the 5% GS / ZIS sample.
[0030] In order to verify the carbon source for generating CH4 and CO, a control experiment was conducted. Figure 4c As shown in the figure, no CH4 and CO production was detected under CO2-free conditions, proving that the carbon source of CH4 and CO comes from the supplied CO2. Therefore, the experimental comparison confirmed that the production of CH4 and CO only occurs when the light source, CO2, sacrificial agent and catalyst are present at the same time. Figure 4d 、 Figure 4e The methane and carbon monoxide yields of GS / ZIS, ZIS, and GS samples were compared. The amounts of methane and carbon monoxide produced increased with increasing reaction time. After 4 hours of reaction, the methane yield of 5% GS / ZIS was 63.2 μmol·g⁻¹ and the carbon monoxide yield was 102 μmol·g⁻¹, significantly higher than those of GS and ZIS. Figure 4f The cycling stability of the 5%GS / ZIS sample was evaluated, and the performance decreased slightly after four cycle tests, indicating that it has excellent cycling stability.
[0031] Figure 5a The transient photocurrent test investigates the photocurrent response of the prepared samples under photoswitching conditions. The 5% GS / ZIS sample prepared in Example 2 exhibits the highest photocurrent response, demonstrating excellent separation efficiency of photogenerated electron-hole pairs under illumination. Due to the S-type heterojunction structure, the mobility of photogenerated electrons toward the catalyst surface is enhanced, thereby improving charge separation efficiency. Figure 5b Electrochemical impedance spectroscopy (EIS) showed that compared with ZIS and GS, the arc radius of the 5% GS / ZIS composite material was the smallest and the impedance value was the lowest, indicating that its electron transfer was easier. Figure 5c It can be seen that the steady-state fluorescence peak intensity of 5% GS / ZIS prepared in Example 2 is the lowest, indicating that the composite sample exhibits an efficient charge carrier separation process. Figure 5d The average carrier lifetime in 5% GS / ZIS was measured to be 4.120 ns in transient fluorescence spectroscopy, significantly longer than that of GS and ZIS. The heterojunction structure can effectively delay charge recombination. Figure 5e and Figure 5f The UV-visible diffuse reflectance spectra of ZIS and GS and the band gaps calculated by Tauc plots are shown. Figure 5g It can be seen from the VB-XPS spectra of ZIS and GS that the valence bands of ZIS and GS are 1.77 eV and 1.65 eV, respectively. Figure 5h The energy band structure diagram based on the above conditions is shown in Figure 2. In summary, the introduction of GS into ZIS to form an S-type heterojunction is beneficial to improving the charge separation ability and suppressing carrier recombination, thereby improving the photocatalytic efficiency.
[0032] To reveal the mechanism of the introduction of GS on the extraction and directional accumulation of photogenerated charges, the surface potentials of ZIS, GS, and 5% GS / ZIS prepared in Example 2 were dynamically detected using surface photovoltage images collected in situ by Kelvin probe force microscopy (KPFM). The surface photovoltage distribution images of ZIS, GS, and 5% GS / ZIS are shown in Figures 6a, Figure 6b 、 Figure 6c As shown in the figure, the surface potential difference of 5%GS / ZIS after illumination (ΔE = 32.39 mV) is significantly greater than that of ZIS (ΔE = 18.55 mV) and GS (ΔE = 18.01 mV). This confirms that photogenerated electrons migrate from ZIS to GS, and holes migrate from GS to ZIS, leading to spatial separation of electrons and holes. Based on this analysis, 5%GS / ZIS drives photoelectrons and photoholes to move simultaneously in opposite directions, promoting the separation and migration of photogenerated electrons (e⁻) and holes (h⁺).
[0033] Example 6 Figure 7a is the XRD analysis diagram of the recovered 5% GS / ZIS sample after the photocatalytic reaction; Figure 7b It is the XPS graph before and after 5% GS / ZIS reaction; Figure 7c This is the Zn 2p spectrum before and after the 5% GS / ZIS reaction. Figure 7d is the In 3d energy spectrum before and after the 5% GS / ZIS reaction; Figure 7e is the S 2p energy spectrum before and after the 5% GS / ZIS reaction; Figure 7f is the Ga 2p energy spectrum of 5% GS / ZIS before and after the reaction; by comparing the diffraction peak position and intensity of the 5% GS / ZIS sample before and after the reaction and the high-resolution photoelectron energy spectrum of Zn 2p, In 3d, S 2p and Ga2 orbitals, it can be seen that the morphology, structure and composition of the 5% GS / ZIS prepared in Example 2 did not change significantly after the photocatalytic CO2 reduction reaction. This phenomenon shows that the 5% GS / ZIS sample has excellent stability.
Claims
1. A method for preparing a gallium sulfide / indium zinc sulfide composite photocatalytic material, characterized in that: Please follow the steps below to implement it: Step 1, preparing gallium sulfide; Step 2: Dissolve ZnCl2, InCl3·4H2O and TAA in a mixed solution of water and ethylene glycol, add citric acid to the mixed solution and mix evenly, then add gallium sulfide from step 1, transfer the mixture into a sealed reactor and place it in an electric constant temperature blast drying oven for reaction, and after the reaction is completed, cool the mixed solution to room temperature, and then centrifuge, wash and vacuum dry to obtain a gallium sulfide / indium zinc sulfide composite photocatalyst material.
2. The method for preparing the gallium sulfide / indium zinc sulfide composite photocatalytic material according to claim 1, wherein: In the step 1, specifically: L-cysteine and gallium chloride are dissolved in water, and then the uniformly mixed solution is transferred into a reactor, sealed, and placed in an electric constant-temperature forced air drying oven for reaction. After the reaction is completed, the mixed solution is cooled to room temperature, and then centrifuged, washed, and vacuum dried to obtain gallium sulfide.
3. The method for preparing the gallium sulfide / indium zinc sulfide composite photocatalytic material according to claim 2, wherein: The molar ratio of L-cysteine to gallium chloride is 1:1.
5.
4. The method for preparing the gallium sulfide / indium zinc sulfide composite photocatalytic material according to claim 2, wherein: The reaction temperature is 120°C-160°C, and the reaction time is 10h-15h; the vacuum drying temperature is 60°C-100°C, and the vacuum drying time is 6h-12h.
5. The method for preparing the gallium sulfide / indium zinc sulfide composite photocatalytic material according to claim 1, wherein: In step 2, the molar ratio of ZnCl2, InCl3·4H2O, TAA, and citric acid is 1:2:4:1; and the amount of gallium sulfide added is 0.5%-15% of the molar amount of ZnCl2.
6. The method for preparing the gallium sulfide / indium zinc sulfide composite photocatalytic material according to claim 1, wherein: In the step 2, the reaction temperature is 100° C.-150° C., and the reaction time is 10 h-20 h; the vacuum drying temperature is 60° C.-100° C., and the vacuum drying time is 6 h-12 h.
7. Gallium sulfide / indium zinc sulfide composite photocatalytic material, characterized in that: It consists of an indium zinc sulfide-based catalytic material and gallium sulfide on the surface of the indium zinc sulfide-based catalytic material.
8. Use of the gallium sulfide / indium zinc sulfide composite photocatalytic material according to any one of claims 1 to 7 in photocatalytic reduction of carbon dioxide.