Z-type heterojunction photocatalyst with high reducing capacity as well as preparation method and application of Z-type heterojunction photocatalyst

Abstract

The invention discloses a high-reducing-capacity Z-type heterojunction photocatalyst as well as a preparation method and application thereof, and belongs to the technical field of photoelectric catalysts. The Z-type heterojunction photocatalyst is prepared by compounding ternary In-based metal sulfide MInS and MS nanoparticles formed in situ through a light induction technology, and the heterojunction material is named as MS / MInS. The preparation method comprises the following steps: synthesizing a ternary In-based metal sulfide semiconductor material MInS; the preparation method comprises the following steps: dispersing MInS in a solvent, and carrying out light treatment for a period of time under the protection of inert gas in a stirring state; and washing, centrifuging and drying to obtain the Z-type MS / MInS heterojunction photocatalyst. The preparation method disclosed by the invention is simple in process and mild and controllable in preparation condition, and has important practical application value for developing a metal sulfide Z-type heterojunction photocatalytic material with high efficiency, high oxidation-reduction capability and high chemical stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of photocatalysts, and specifically relates to a Z-scheme heterojunction photocatalyst with high reduction ability, a preparation method thereof, and an application thereof. Background Art

[0002] Acetophenone and its derivatives are important monomeric compounds obtained by lignin degradation. Long-chain carbon-based vicinal diol products (carbon atom number > 16) can be prepared by catalytic reduction of the pinacol C-C coupling reaction. The coupling product can not only be used as a pharmaceutical and polyester intermediate, but also as a precursor for the production of biodiesel or bio-aviation kerosene fuel. Although a variety of acetophenone pinacol coupling methods have been developed currently, they all have significant drawbacks: (i) traditional methods require the use of a stoichiometric excess of metal catalysts; (ii) in an electrochemical system, an expensive ionic liquid is relied on as a solvent, and a carbon fiber paper electrode needs to be used; (iii) an exogenous sacrificial agent (such as tertiary amine, hydrazine hydrate, Hantzsch ester) needs to be added during the photoinduced conversion process. The use of excessive metal reagents and toxic solvents brings non-negligible environmental problems.

[0003] Using solar energy for photocatalytic valorization of biomass-derived molecules, which is a renewable, clean, and abundant energy source, has become an attractive green process for the production of value-added chemicals and renewable biofuels. However, so far, due to the large reduction potential of aldehydes and ketones (E*red(hypnone / hypnone. - ) = -2.11 V), there is no effective photocatalyst available for the reduction coupling of acetophenone or its derivatives under visible light.

[0004] In the photocatalytic acetophenone pinacol coupling reaction system, compared with single photocatalysts and traditional heterojunction photocatalysts, direct Z-scheme heterojunction photocatalysts can effectively separate electrons and holes, retain strong reduction and strong oxidation active sites, and expand the spectral response range and other advantages. Developing a novel Z-scheme heterojunction photocatalyst with high reduction ability has important scientific significance for realizing the efficient conversion of aromatic ketone compounds and the selective regulation of coupling products driven by sunlight, and has important research value and application potential in the field of renewable energy utilization. Summary of the Invention

[0005] In order to make up for the deficiencies of the prior art, one of the purposes of the present invention is to provide a Z-scheme heterojunction photocatalyst with high reduction ability; the second purpose of the present invention is to provide a preparation method of a Z-scheme heterojunction photocatalyst with high reduction ability; the third purpose of the present invention is to provide an application of a Z-scheme heterojunction photocatalyst with high reduction ability.

[0006] To achieve the above purposes, the specific technical solutions provided by the present invention are as follows:

[0007] The present invention provides a Z-scheme heterojunction photocatalyst with high reduction ability. The Z-scheme heterojunction photocatalyst is prepared by compositing MS nanoparticles in-situ formed from ternary In-based metal sulfide MInS through a light-induced technology (LH). The heterojunction material is named MS / MInS.

[0008] Preferably, the metal sulfide semiconductor material MInS is one of ZnInS, CuInS, CdInS, MgInS, AgInS or SnInS.

[0009] Preferably, the morphology of the metal sulfide semiconductor material MInS is nanoparticles, nanosheets, nanospheres or nanorods.

[0010] The present invention provides a preparation method of a Z-scheme heterojunction photocatalyst with high reduction ability. The specific steps are as follows:

[0011] First, synthesize the ternary In-based metal sulfide semiconductor material MInS;

[0012] Then, disperse MInS in a solvent, and under stirring, perform light irradiation treatment (LH technology, light-induced heterostructure) under the protection of an inert gas;

[0013] Finally, obtain the Z-scheme MS / MInS heterojunction photocatalyst through washing, centrifugation, and drying.

[0014] Preferably, the preparation method of the ternary In-based metal sulfide semiconductor material MInS is as follows: Dissolve MCl x , InCl3, and cetyltrimethylammonium bromide (CTAB) in deionized water. Under magnetic stirring, add thioacetamide (TAA) to the above solution, continue stirring, transfer the mixed solution to a stainless steel Teflon-lined autoclave, seal it, and place it in a homogeneous reactor. Hydrothermally react at 150 °C to 200 °C for 10 h to 24 h; then naturally cool the autoclave to room temperature; wash the obtained precipitate with water and alcohol, and dry it in an oven at 60 °C for 12 h to obtain the MInS material.

[0015] Specifically, the molar ratio of M / In of the metal sulfide semiconductor material MInS is 0.25 to 2.0; preferably, the molar ratio of the precursor MCl x / InCl3 of the semiconductor material MInS is 0.75 to 1.25.

[0016] Preferably, the light treatment conditions are as follows: the light wavelength is 320 nm to 465 nm, the light power is 5 W to 300 W, the light treatment time is 0.5 h to 12 h, and the temperature is from room temperature to 60 °C.

[0017] Preferably, the solvent is one of water, methanol, ethanol, isopropanol, acetonitrile or ethyl acetate.

[0018] Preferably, the inert gas is N2, which is used to displace the air in the system.

[0019] The present invention also provides an application of a Z-type heterojunction photocatalyst with high reduction ability in the photocatalytic reduction pinacol coupling reaction of acetophenone and its derivatives.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) The Z-type MS / MInS heterojunction prepared by the present invention has a low bandgap, high reducibility, good carrier separation efficiency and high chemical stability.

[0022] (2) The preparation method of the Z-type heterojunction photocatalyst provided by the present invention has a simple process, low cost and can be prepared in large quantities; the preparation conditions for preparing the Z-type heterostructure are mild and controllable, which has important practical application value for the development of metal sulfide Z-type heterojunction photocatalytic materials with high efficiency, high redox ability and high chemical stability.

[0023] (3) The Z-type heterojunction photocatalyst with high reduction ability provided by the present invention realizes the photocatalytic reduction of lignin-based acetophenone and its derivatives in the pinacol coupling reaction under mild conditions to prepare high-value coupling products, making full use of lignin resources and realizing its value-added. Description of the Drawings

[0024] Figure 1 It is a schematic diagram for the preparation of the metal sulfide MS / MInS heterojunction photocatalyst of the present invention;

[0025] Figure 2 It is a structural characterization diagram of the ZnS / ZnInS heterojunction photocatalyst prepared in Example 1 of the present invention;

[0026] Figure 3 It is a comparison of the optoelectronic properties between the ZnS / ZnInS heterojunction photocatalyst prepared in Example 1 of the present invention and the ZnInS semiconductor material prepared in step (1) of Example 1;

[0027] Figure 4 It is a schematic diagram of the photocatalytic reduction pinacol coupling reaction of acetophenone and its derivatives of the present invention;

[0028] Figure 5This is the mechanism diagram of the photocatalytic reduction of acetophenone pinacol coupling reaction by the ZnS / ZnInS heterojunction photocatalyst of the present invention;

[0029] Figure 6 This is the gas chromatograph-mass spectrometry result diagram of the photocatalytic reduction coupling reaction of acetophenone by the ZnS / ZnInS heterojunction photocatalyst of the present invention. Detailed implementation manners

[0030] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] As Figure 1 shown, a Z-scheme heterojunction photocatalyst with high reduction ability is prepared by in-situ formation of MS nanoparticles by a ternary In-based metal sulfide (MInS) through a light-induced technology (LH), and the heterojunction material is named MS / MInS.

[0032] The preparation method of the Z-scheme heterojunction photocatalyst is as follows: synthesize a ternary In-based metal sulfide semiconductor material MInS; disperse MInS in a solvent, and under stirring, perform light irradiation treatment under the protection of an inert gas, and then obtain the Z-scheme MS / MInS heterojunction photocatalyst through washing, centrifugation, and drying.

[0033] Among them, the preparation method of the ternary In-based metal sulfide semiconductor material MInS is as follows: dissolve MCl x , InCl3, and cetyltrimethylammonium bromide (CTAB) into deionized water. Under magnetic stirring, add thioacetamide (TAA) to the above solution, continue stirring, transfer the mixed solution to a stainless steel Teflon-lined autoclave, seal it and place it in a homogeneous reactor, and perform hydrothermal treatment at 150-200 °C for 10-24 h. Then, naturally cool the autoclave to room temperature. Wash the obtained precipitate with water and alcohol, and dry it in an oven at 60 °C for 12 h to obtain the MInS material.

[0034] Example 1

[0035] Step 1: Preparation of semiconductor material ZnInS: Weigh ZnCl2 (136.3 mg), InCl3·4H2O (293.2 mg), and CTAB (120.3 mg) and dissolve them in a flask containing 60 mL of deionized water. After dispersing for 30 min under magnetic stirring, add TAA (270.5 mg) to the above solution. Subsequently, transfer the mixed solution to a 100 mL high-pressure tetrafluoro inner liner, seal it, and place it in a homogeneous reactor to maintain at 160 °C for 16 h. After natural cooling, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the ternary ZnInS (Zn / In = 1:1) semiconductor material.

[0036] Step 2: Weigh 200 mg of the ternary ZnInS (Zn / In = 1:1) material prepared above and disperse it in 30 mL of isopropanol solution. After dispersing for 30 min under magnetic stirring, transfer the solution to a photoreactor, displace the air in the reaction tube with nitrogen 5 times, and irradiate it under LED-420 nm wavelength for 2 h. Subsequently, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the ZnS / ZnInS (Zn / In = 1:1) heterojunction photocatalytic material.

[0037] Add the ZnS / ZnInS (Zn / In = 1:1) heterojunction photocatalyst (10 mg) prepared in Example 1 to the test tube of the photocatalytic reactor, and add 0.1 mmol of acetophenone and 3 mL of isopropanol solution. Displace the air in the reaction tube with nitrogen 5 times. Then place the reaction tube in the photocatalytic reactor device, perform magnetic stirring at room temperature, with a stirring speed of 500 revolutions per minute, and irradiate it under a 420 nm (9.6 W) band of an LED light source for 1 h. Then add 0.05 mmol of dodecane as an internal standard to the reaction solution, fully oscillate it, sample and filter it. The filter cake is the catalyst and can be recycled. The filtrate is analyzed by gas chromatography to calculate that the conversion rate of acetophenone is 99.9%, the selectivity of 2,3-diphenyl-2,3-butanediol is 98%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol is 2%.

[0038] The ZnS / ZnInS (Zn / In = 1:1) heterojunction photocatalyst (10 mg) prepared in Example 1 was added to a test tube of a photocatalytic reactor, and 0.1 mmol of acetophenone and 3 mL of isopropanol solution were added. The air in the reaction test tube was replaced with nitrogen 5 times. Then the reaction test tube was placed in a photocatalytic reactor device, and magnetic stirring was carried out at room temperature with a stirring speed of 500 revolutions per minute. At the same time, it was irradiated under a 300W PLS-SXE300 xenon lamp light source (320 - 780 nm) in the full wavelength band for 0.5 h. Then 0.05 mmol of dodecane as an internal standard was added to the reaction solution. After sufficient oscillation, the sample was filtered. The filter cake was the catalyst and could be recycled. The filtrate was analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone was 97%, the selectivity of 2,3-diphenyl-2,3-butanediol was 96%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol was 4%.

[0039] The ZnS / ZnInS (Zn / In = 1:1) heterojunction photocatalyst (10 mg) prepared in Example 1 was added to a test tube of a photocatalytic reactor, and 0.1 mmol of acetophenone and 3 mL of isopropanol solution were added. The air in the reaction test tube was replaced with nitrogen 5 times. Then the reaction test tube was placed in a solar concentrator system device, and magnetic stirring was carried out at room temperature with a stirring speed of 500 revolutions per minute. At the same time, it was irradiated under sunlight for 1 h. Then 0.05 mmol of dodecane as an internal standard was added to the reaction solution. After sufficient oscillation, the sample was filtered. The filter cake was the catalyst and could be recycled. The filtrate was analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone was 99%, the selectivity of 2,3-diphenyl-2,3-butanediol was 98%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol was 2%.

[0040] The ZnS / ZnInS (Zn / In = 1:1) heterojunction photocatalyst (10 mg) prepared in Example 1 was added to a test tube of a photocatalytic reactor, and 0.1 mmol of p-methylacetophenone and 3 mL of isopropanol solution were added. The air in the reaction test tube was replaced with nitrogen 5 times. Then the reaction test tube was placed in a photocatalytic reactor device, and magnetic stirring was carried out at room temperature with a stirring speed of 500 revolutions per minute. At the same time, it was irradiated under an LED light source at 420 nm (9.6W) for 6 h. Then 0.05 mmol of dodecane as an internal standard was added to the reaction solution. After sufficient oscillation, the sample was filtered. The filter cake was the catalyst and could be recycled. The filtrate was analyzed by gas chromatography and calculated to obtain: the conversion rate of p-methylacetophenone was 98%, the selectivity of 2,3-di(p-tolyl)-2,3-butanediol was 91%, and the selectivity of 2-methyl-3-(p-tolyl)-2,3-butanediol was 8%.

[0041] The ZnS / ZnInS (Zn / In = 1:1) heterojunction photocatalyst (10 mg) prepared in Example 1 was added to a test tube of a photocatalytic reactor, and 0.1 mmol of p-methoxyacetophenone and 3 mL of isopropanol solution were added. The air in the reaction test tube was replaced with nitrogen 5 times. Then the reaction test tube was placed into the photocatalytic reactor device and magnetically stirred at room temperature with a stirring speed of 500 revolutions per minute. At the same time, it was irradiated at a wavelength of 420 nm (9.6 W) under an LED light source for 6 h. Then 0.05 mmol of dodecane as an internal standard was added to the reaction solution. After sufficient oscillation, the sample was filtered. The filter cake was the catalyst and could be recycled. The filtrate was analyzed by gas chromatography and calculated to obtain: the conversion rate of p-methoxyacetophenone was 99%, the selectivity of 2,3-bis(4-hydroxyphenyl)-2,3-butanediol was 88%, and the selectivity of 2-(4-hydroxyphenyl)-3-methyl-2,3-butanediol was 12%.

[0042] The ZnS / ZnInS (Zn / In = 1:1) heterojunction photocatalyst (10 mg) prepared in Example 1 was added to a test tube of a photocatalytic reactor, and 0.1 mmol of 2,3-dimethoxyacetophenone and 3 mL of isopropanol solution were added. The air in the reaction test tube was replaced with nitrogen 5 times. Then the reaction test tube was placed into the photocatalytic reactor device and magnetically stirred at room temperature with a stirring speed of 500 revolutions per minute. At the same time, it was irradiated at a wavelength of 420 nm (9.6 W) under an LED light source for 6 h. Then 0.05 mmol of dodecane as an internal standard was added to the reaction solution. After sufficient oscillation, the sample was filtered. The filter cake was the catalyst and could be recycled. The filtrate was analyzed by gas chromatography and calculated to obtain: the conversion rate of 2,3-dimethoxyacetophenone was 98%, the selectivity of 2,3-bis(2,3-dimethoxyphenyl)-2,3-butanediol was 98%, and the selectivity of 2-(2,3-dimethoxyphenyl)-3-methyl-2,3-butanediol was 2%.

[0043] As Figure 2 shown are the structural characterization diagrams of the prepared ZnS / ZnInS heterojunction photocatalyst, which prove the formation of ZnS on ZnInS and are one of the evidences for the successful construction of the heterostructure. As Figure 3 shown is the comparison of the optoelectronic properties between the prepared ZnS / ZnInS heterojunction photocatalyst and the ZnInS semiconductor material prepared in step (1) of Example 1. The differences in optoelectronic properties between the ZnS / ZnInS heterojunction material and the ZnInS semiconductor material are compared, showing that the ZnS / ZnInS heterojunction material has higher charge separation efficiency and stronger reduction ability.

[0044] As Figure 4 and Figure 5 shown are respectively the equation and mechanism diagram of the ZnS / ZnInS heterojunction material used in the pinacol coupling reaction, Figure 6It is the gas chromatography - mass spectrometry result of the corresponding reductive coupling reaction.

[0045] Example 2

[0046] Step 1: Prepare the semiconductor material CuInS. Weigh and add CuCl2·2H2O (170.5 mg), InCl3·4H2O (293.2 mg), and CTAB (120.3 mg) in a flask containing 60 mL of deionized water. After dispersing for 30 min under magnetic stirring, add TAA (270.5 mg) to the above solution. Then transfer the mixed solution to a 100 mL high - pressure tetrafluoro - lined container, seal it, and place it in a homogeneous reactor at 160 °C for 16 h. After natural cooling, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the ternary CuInS (Cu / In = 1:1) semiconductor material.

[0047] Step 2: Weigh 200 mg of the ternary CuInS (Cu / In = 1:1) material prepared above and disperse it in 30 mL of isopropanol solution. After dispersing for 30 min under magnetic stirring, transfer this solution to a photoreactor. Replace the air in the reaction tube with nitrogen 5 times, irradiate it under LED - 420 nm wavelength for 2 h. Then wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the CuInS (Cu / In = 1:1) heterojunction photocatalytic material.

[0048] Add the CuInS (Cu / In = 1:1) heterojunction photocatalyst (10 mg) prepared in this Example 2 into the test tube of the photocatalytic reactor, add 0.1 mmol of acetophenone and 3 mL of isopropanol solution, and replace the air in the reaction tube with nitrogen 5 times. Then place the reaction tube into the photocatalytic reactor device, perform magnetic stirring at room temperature with a stirring speed of 500 revolutions per minute, and irradiate it under an LED light source at 420 nm (9.6 W) for 1 h. Then add 0.05 mmol of dodecane as an internal standard to the reaction solution, fully oscillate it, sample and filter. The filter cake is the catalyst and can be recycled. The filtrate is analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone is 88%, the selectivity of 2,3 - diphenyl - 2,3 - butanediol is 96%, and the selectivity of 2 - methyl - 3 - phenylbutane - 2,3 - diol is 4%.

[0049] Example 3

[0050] Step 1: Prepare semiconductor material CdInS (Cd / In = 1:1): Weigh and add CdCl2·2.5H2O (228.4 mg), InCl3·4H2O (293.2 mg), and CTAB (120.3 mg) in stoichiometric proportions and dissolve them in a flask containing 60 mL of deionized water. After dispersing for 30 min under magnetic stirring, add TAA (270.5 mg) to the above solution. Subsequently, transfer the mixed solution to a 100 mL high-pressure tetrafluoro liner, seal it, and place it in a homogeneous reactor to maintain at 160 °C for 16 h. After natural cooling, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the ternary CdInS (Cd / In = 1:1) semiconductor material.

[0051] Step 2: Weigh 200 mg of the ternary CdInS (Cu / In = 1:1) material prepared above and disperse it in 30 mL of isopropyl alcohol solution, and disperse it for 30 min under magnetic stirring. Subsequently, transfer this solution to a photoreactor, displace the air in the reaction tube with nitrogen 5 times, irradiate it under LED-420 nm wavelength for 2 h. Then wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the CdInS (Cd / In = 1:1) heterojunction photocatalytic material.

[0052] Add the CdS / CdInS (Cd / In = 1:1) heterojunction photocatalyst (10 mg) prepared in Example 3 to the test tube of the photocatalytic reactor, and add 0.1 mmol of acetophenone and 3 mL of IPA solution, and displace the air in the reaction tube with nitrogen 5 times. Then place the reaction tube into the photocatalytic reactor device, carry out magnetic stirring at room temperature, the stirring speed is 500 revolutions per minute, and at the same time irradiate it under the 420 nm (9.6 W) band of the LED light source for 1 h. Then add 0.05 mmol of dodecane as an internal standard to the reaction solution, fully oscillate and then sample and filter. The filter cake is the catalyst and can be recycled. The filtrate is analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone is 90%, the selectivity of 2,3-diphenyl-2,3-butanediol is 95%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol is 5%.

[0053] Example 4

[0054] Step 1: Prepare semiconductor material AgInS (Ag / In = 1:1): Weigh and add AgNO3 (169.8 mg), InCl3·4H2O (293.2 mg), and CTAB (120.3 mg) in stoichiometric proportions into a flask containing 60 mL of deionized water. After dispersing for 30 min under magnetic stirring, add TAA (270.5 mg) into the above solution. Subsequently, transfer the mixed solution to a 100 mL high-pressure tetrafluoro inner liner, seal it, and place it in a homogeneous reactor to maintain at 160 °C for 16 h. After natural cooling, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the ternary AgInS (Ag / In = 1:1) semiconductor material.

[0055] Step 2: Weigh 200 mg of the ternary AgS / AgInS (Ag / In = 1:1) material prepared above and disperse it in 30 mL of isopropanol solution. After dispersing for 30 min under magnetic stirring, transfer the solution to a photoreactor, displace the air in the reaction tube with nitrogen 5 times, and irradiate it under a LED at a wavelength of 420 nm for 2 h. Then, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the AgS / AgInS (Ag / In = 1:1) heterojunction photocatalytic material.

[0056] Add the AgS / AgInS (Ag / In = 1:1) heterojunction photocatalyst (10 mg) prepared in Example 4 of this embodiment into a test tube of a photocatalytic reactor, add 0.1 mmol of acetophenone and 3 mL of IPA solution, and displace the air in the reaction tube with nitrogen 5 times. Then, place the reaction tube into the photocatalytic reactor device, perform magnetic stirring at room temperature with a stirring speed of 500 revolutions per minute, and irradiate it under a LED light source at a wavelength of 420 nm (9.6 W) for 1 h. Then, add 0.05 mmol of dodecane as an internal standard into the reaction solution, fully oscillate it, sample and filter it. The filter cake is the catalyst and can be recycled. The filtrate is analyzed by gas chromatography to calculate that the conversion rate of acetophenone is 88%, the selectivity of 2,3-diphenyl-2,3-butanediol is 94%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol is 6%.

[0057] Example 5

[0058] Step 1: Prepare semiconductor material SnInS (Sn / In = 1:1): Weigh and add SnCl4·5H2O (350.6 mg), InCl3·4H2O (293.2 mg), and CTAB (120.3 mg) in a flask containing 60 mL of deionized water according to stoichiometric ratios. After dispersing for 30 min under magnetic stirring, add TAA (270.5 mg) to the above solution. Subsequently, transfer the mixed solution to a 100 mL high-pressure tetrafluoro inner liner, seal it, and place it in a homogeneous reactor to maintain at 160 °C for 16 h. After natural cooling, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the ternary SnInS (Sn / In = 1:1) semiconductor material.

[0059] Step 2: Weigh 200 mg of the ternary SnS / SnInS (Sn / In = 1:1) material prepared above and disperse it in 30 mL of isopropanol solution, and disperse it for 30 min under magnetic stirring. Subsequently, transfer this solution to a photoreactor, displace the air in the reaction tube with nitrogen 5 times, irradiate it under LED-420 nm wavelength for 2 h. Then, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the SnS / SnInS (Sn / In = 1:1) heterojunction photocatalytic material.

[0060] Add the SnS / SnInS (Sn / In = 1:1) heterojunction photocatalyst (10 mg) prepared in Example 5 to the test tube of the photocatalytic reactor, and add 0.1 mmol of acetophenone and 3 mL of IPA solution. Displace the air in the reaction tube with nitrogen 5 times. Then, place the reaction tube into the photocatalytic reactor device, perform magnetic stirring at room temperature, with a stirring speed of 500 revolutions per minute. At the same time, irradiate it under an LED light source at 420 nm (9.6 W) for 1 h. Then, add 0.05 mmol of dodecane as an internal standard to the reaction solution, fully oscillate it, sample and filter. The filter cake is the catalyst and can be recycled. The filtrate is analyzed by gas chromatography to calculate that the conversion rate of acetophenone is 85%, the selectivity of 2,3-diphenyl-2,3-butanediol is 95%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol is 5%.

[0061] Example 6

[0062] Step 1: Prepare semiconductor material ZnInS (Zn / In = 0.75:1): Weigh and add ZnCl2 (102.2 mg), InCl3·4H2O (293.2 mg), and CTAB (120.3 mg) in stoichiometric proportions and dissolve them in a flask containing 60 mL of deionized water. After dispersing for 30 min under magnetic stirring, add TAA (270.5 mg) to the above solution. Subsequently, transfer the mixed solution to a 100 mL high-pressure tetrafluoro liner, seal it, and place it in a homogeneous reactor to maintain at 160 °C for 16 h. After natural cooling, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the ternary ZnInS (Zn / In = 0.75:1) semiconductor material.

[0063] Step 2: Weigh 200 mg of the ternary ZnS / ZnInS (Zn / In = 0.75:1) material prepared above and disperse it in 30 mL of isopropanol solution, and disperse it for 30 min under magnetic stirring. Subsequently, transfer the solution to a photoreactor, displace the air in the reaction tube with nitrogen 5 times, irradiate it under LED-420 nm wavelength for 2 h. Then, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the ZnS / ZnInS (Zn / In = 0.75:1) heterojunction photocatalytic material.

[0064] Add the ZnS / ZnInS (Zn / In = 0.75:1) heterojunction photocatalyst (10 mg) prepared in Example 6 to the test tube of the photocatalytic reactor, and add 0.1 mmol of acetophenone and 3 mL of isopropanol solution. Displace the air in the reaction tube with nitrogen 5 times. Then, place the reaction tube into the photocatalytic reactor device, stir it magnetically at room temperature, and the stirring speed is 500 revolutions per minute. At the same time, irradiate it under the LED light source at 420 nm (9.6 W) for 1 h. Then, add 0.05 mmol of dodecane as an internal standard to the reaction solution, fully oscillate it, sample and filter it. The filter cake is the catalyst and can be recycled. The filtrate is analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone is 28%, the selectivity of 2,3-diphenyl-2,3-butanediol is 97%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol is 3%.

[0065] Example 7

[0066] Step 1: Prepare semiconductor material ZnInS (Zn / In = 1.25:1): Weigh and add ZnCl2 (170.4 mg), InCl3·4H2O (293.2 mg), and CTAB (120.3 mg) in stoichiometric proportions into a flask containing 60 mL of deionized water. After dispersing for 30 min under magnetic stirring, add TAA (270.5 mg) to the above solution. Subsequently, transfer the mixed solution to a 100 mL high-pressure tetrafluoro liner, seal it, and place it in a homogeneous reactor at 160 °C for 16 h. After natural cooling, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the ternary ZnInS (Zn / In = 1.25:1) semiconductor material.

[0067] Step 2: Weigh 200 mg of the ternary ZnS / ZnInS (Zn / In = 1.25:1) material prepared above and disperse it in 30 mL of isopropanol solution. After dispersing for 30 min under magnetic stirring, transfer this solution to a photoreactor. Replace the air in the reaction tube with nitrogen 5 times, and irradiate it under LED-420 nm wavelength for 2 h. Then, wash the obtained precipitate 3 times with water and 2 times with alcohol, and dry it in an oven at 60 °C for 12 h to obtain the ZnS / ZnInS (Zn / In = 1.25:1) heterojunction photocatalytic material.

[0068] Add the ZnS / ZnInS (Zn / In = 1.25:1) heterojunction photocatalyst (10 mg) prepared in Example 7 to the test tube of the photocatalytic reactor, add 0.1 mmol of acetophenone and 3 mL of isopropanol solution, and replace the air in the reaction tube with nitrogen 5 times. Then, place the reaction tube into the photocatalytic reactor device, stir it magnetically at room temperature with a stirring speed of 500 revolutions per minute, and irradiate it under an LED light source at 420 nm (9.6 W) for 1 h. Then, add 0.05 mmol of dodecane as an internal standard to the reaction solution, fully oscillate it, sample and filter it. The filter cake is the catalyst and can be recycled. The filtrate is analyzed by gas chromatography to calculate that the conversion rate of acetophenone is 82%, the selectivity of 2,3-diphenyl-2,3-butanediol is 95%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol is 5%.

[0069] Comparative Example 1

[0070] ZnCl2 (34.1 mg) and InCl3·4H2O (293.2 mg) and CTAB (120.3 mg) were weighed and dissolved in a flask containing 60 mL of deionized water in a stoichiometric ratio. After dispersion under magnetic stirring for 30 min, TAA (270.5 mg) was added to the above solution. The mixed solution was then transferred to a 100 mL high-pressure polytetrafluoroethylene liner, sealed, and placed in a homogeneous reactor at 160°C for 16 h. After natural cooling, the obtained precipitate was washed with water 3 times, washed with alcohol 2 times, and dried in an oven at 60°C for 12 h to obtain the ternary ZnInS (Zn / In=0.25:1) semiconductor material.

[0071] The ZnInS (Zn / In=0.25:1) semiconductor photocatalyst (10 mg) prepared in Comparative Example 1 was added to a photocatalytic reactor test tube, and 0.1 mmol of acetophenone and 3 mL of isopropanol solution were added. The air in the reaction tube was replaced with nitrogen 5 times. The reaction tube was then placed in a photocatalytic reactor device, magnetically stirred at room temperature at a stirring speed of 500 rpm, and irradiated under a 420 nm (9.6 W) LED light source for 1 h. Then, 0.05 mmol of dodecane as an internal standard was added to the reaction solution. After sufficient shaking, the sample was filtered and the filter cake was used as the catalyst, which could be recycled. The filtrate was subjected to gas chromatography analysis and calculated to obtain: the conversion of acetophenone was 3%, the selectivity of 2,3-diphenyl-2,3-butanediol was 97%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol was 3%.

[0072] Comparative Example 2

[0073] ZnCl2 (136.3 mg) and CTAB (120.3 mg) were weighed in a stoichiometric ratio and dissolved in a flask containing 60 mL of deionized water. After dispersion under magnetic stirring for 30 minutes, TAA (270.5 mg) was added to the above solution. The mixed solution was then transferred to a 100 mL high-pressure tetrafluoroethylene liner, sealed, and placed in a homogeneous reactor at 160°C for 16 hours. After natural cooling, the obtained precipitate was washed with water 3 times, washed with alcohol 2 times, and dried in an oven at 60°C for 12 hours to obtain ZnS semiconductor material.

[0074] The ZnS semiconductor photocatalyst (10 mg) prepared in Comparative Example 2 was added to a test tube of a photocatalytic reactor, and 0.1 mmol of acetophenone and 3 mL of isopropanol solution were added. The air in the reaction test tube was displaced with nitrogen 5 times. Then the reaction test tube was placed into the photocatalytic reactor device and magnetically stirred at room temperature with a stirring speed of 500 revolutions per minute. At the same time, it was irradiated at a wavelength of 420 nm (9.6 W) under an LED light source for 1 h. Then 0.05 mmol of dodecane as an internal standard was added to the reaction solution. After sufficient oscillation, the sample was filtered. The filter cake was the catalyst and could be recycled. The filtrate was analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone was 0%, the selectivity of 2,3-diphenyl-2,3-butanediol was 0%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol was 0%.

[0075] Comparative Example 3

[0076] 0.1 mmol of acetophenone and 10 mg of the previously prepared CuInS catalyst were added to a test tube of a photocatalytic reactor, and 3 mL of IPA solution was added. The air in the reaction test tube was displaced with nitrogen 5 times. Then the reaction test tube was placed into the photocatalytic reactor device and magnetically stirred at room temperature with a stirring speed of 500 revolutions per minute. At the same time, it was irradiated at a wavelength of 420 nm (9.6 W) under an LED light source for 1 h. Then 0.05 mmol of dodecane as an internal standard was added to the reaction solution. After sufficient oscillation, the sample was filtered. The filter cake was the catalyst and could be recycled. The filtrate was analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone was 0%, the selectivity of 2,3-diphenyl-2,3-butanediol was 0%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol was 0%.

[0077] Comparative Example 4

[0078] 0.1 mmol of acetophenone and 10 mg of the previously prepared CdInS catalyst were added to a test tube of a photocatalytic reactor, and 3 mL of IPA solution was added. The air in the reaction test tube was displaced with nitrogen 5 times. Then the reaction test tube was placed into the photocatalytic reactor device and magnetically stirred at room temperature with a stirring speed of 500 revolutions per minute. At the same time, it was irradiated at a wavelength of 420 nm (9.6 W) under an LED light source for 1 h. Then 0.05 mmol of dodecane as an internal standard was added to the reaction solution. After sufficient oscillation, the sample was filtered. The filter cake was the catalyst and could be recycled. The filtrate was analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone was 0%, the selectivity of 2,3-diphenyl-2,3-butanediol was 0%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol was 0%.

[0079] Comparative Example 5

[0080] Add 0.1 mmol of acetophenone, 10 mg of the CdS catalyst prepared above, and 3 mL of IPA solution into the test tube of the photocatalytic reactor. Replace the air in the reaction test tube with nitrogen 5 times. Then place the reaction test tube into the photocatalytic reactor device, carry out magnetic stirring at room temperature with a stirring speed of 500 revolutions per minute, and irradiate it under a LED light source at a wavelength of 420 nm (9.6 W) for 1 h. Then add 0.05 mmol of dodecane as an internal standard to the reaction solution, sample and filter after sufficient oscillation. The filter cake is the catalyst and can be recycled. The filtrate is analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone is 0%, the selectivity of 2,3-diphenyl-2,3-butanediol is 0%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol is 0%.

[0081] Comparative Example 6

[0082] Add 0.1 mmol of acetophenone, 10 mg of C3N4 catalyst, and 3 mL of IPA solution into the test tube of the photocatalytic reactor. Replace the air in the reaction test tube with nitrogen 5 times. Then place the reaction test tube into the photocatalytic reactor device, carry out magnetic stirring at room temperature with a stirring speed of 500 revolutions per minute, and irradiate it under a LED light source at a wavelength of 420 nm (9.6 W) for 1 h. Then add 0.05 mmol of dodecane as an internal standard to the reaction solution, sample and filter after sufficient oscillation. The filter cake is the catalyst and can be recycled. The filtrate is analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone is 0%, the selectivity of 2,3-diphenyl-2,3-butanediol is 0%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol is 0%.

[0083] Comparative Example 7

[0084] Add 0.1 mmol of acetophenone, 10 mg of TiO2 catalyst, and 3 mL of IPA solution into the test tube of the photocatalytic reactor. Replace the air in the reaction test tube with nitrogen 5 times. Then place the reaction test tube into the photocatalytic reactor device, carry out magnetic stirring at room temperature with a stirring speed of 500 revolutions per minute, and irradiate it under a LED light source at a wavelength of 420 nm (9.6 W) for 1 h. Then add 0.05 mmol of dodecane as an internal standard to the reaction solution, sample and filter after sufficient oscillation. The filter cake is the catalyst and can be recycled. The filtrate is analyzed by gas chromatography and calculated to obtain: the conversion rate of acetophenone is 0%, the selectivity of 2,3-diphenyl-2,3-butanediol is 0%, and the selectivity of 2-methyl-3-phenylbutane-2,3-diol is 0%.

[0085] In summary, the above embodiments prove that various ternary In-based metal sulfide materials can be in-situ prepared into MS / MInS heterojunction photocatalysts by the method of the present invention within a certain M / In ratio range. Their high reduction ability shows excellent performance for the pinacol dimerization reaction of ketones; each comparative example compares the pinacol dimerization performance of common metal sulfide and metal oxide semiconductor materials. By measuring and calculating the conduction band and valence band positions of MS and MInS, it is confirmed that the two can form a Z-type heterojunction structure; the excellent photogenerated carrier separation efficiency and high reduction ability of the MS / MInS heterojunction endow it with good catalytic ability in the photocatalytic reduction pinacol coupling reaction of acetophenone and its derivatives.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A Z-scheme heterojunction photocatalyst with high reduction ability, characterized in that, The Z-scheme heterojunction photocatalyst is prepared by compositing MS nanoparticles in-situ formed from ternary In-based metal sulfide MInS through a photo-induced technique, and the heterojunction material is named MS / MInS.

2. The highly reducible Z-scheme heterojunction photocatalyst according to claim 1, wherein The metal sulfide semiconductor material MInS is one of ZnInS, CuInS, CdInS, MgInS, AgInS or SnInS.

3. The Z-scheme heterojunction photocatalyst with high reduction ability according to claim 1, characterized in that, The morphology of the metal sulfide semiconductor material MInS is nanoparticles, nanosheets, nanospheres or nanorods.

4. A preparation method of a highly reducible Z-type heterojunction photocatalyst as described in claim 1, characterized in that, The specific steps of the preparation method are as follows: First, synthesize the ternary In-based metal sulfide semiconductor material MInS; Then, disperse MInS in a solvent and perform light irradiation treatment under stirring and under the protection of an inert gas; Finally, the Z-scheme MS / MInS heterojunction photocatalyst is obtained through washing, centrifugation and drying.

5. The preparation method according to claim 4, characterized in that, The preparation method of the ternary In-based metal sulfide semiconductor material MInS is as follows: dissolve MCl x , InCl3, and cetyltrimethylammonium bromide in deionized water. Under magnetic stirring, add thioacetamide to the above solution, continue stirring, transfer the mixed solution to a stainless steel Teflon-lined autoclave, seal it, and place it in a homogeneous reactor. Hydrothermal react at 150 °C to 200 °C for 10 h to 24 h; then naturally cool the autoclave to room temperature. Wash the obtained precipitate with water and alcohol, and then dry it in an oven at 60 °C for 12 h to obtain the MInS material.

6. The preparation method according to claim 4 or 5, characterized in that The molar ratio of M / In of the metal sulfide semiconductor material MInS is 0.25 to 2.

0.

7. The preparation method according to claim 4, characterized in that, The light treatment conditions are as follows: the light wavelength is 320 nm to 465 nm, the light power is 5 W to 300 W, and the light treatment time is 0.5 h to 12 h. ， The temperature is from room temperature to 60 °C.

8. The preparation method according to claim 4, characterized in that: The solvent is one of water, methanol, ethanol, isopropanol, acetonitrile or ethyl acetate.

9. The preparation method according to claim 4, characterized in that: The inert gas is N2, which is used to displace the air in the system.

10. Use of a Z-scheme heterojunction photocatalyst with high reduction ability as described in claim 1 in the photocatalytic reduction pinacol coupling reaction of acetophenone and its derivatives.

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