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CN-121988407-A - Photocatalyst, and preparation method and application thereof

CN121988407ACN 121988407 ACN121988407 ACN 121988407ACN-121988407-A

Abstract

The invention relates to the field of photocatalysis, in particular to the field of hydrogen production by selective oxidative coupling of organic matters, and specifically relates to a photocatalyst, a preparation method and application thereof. The invention provides a photocatalyst for constructing spatial separation of oxidation sites and reduction sites on a CdS rod, namely, metal sulfide reduction promoters are loaded at two ends of the CdS rod, coS oxidation promoters are loaded on a rod body, and under illumination, photo-generated electrons migrate to the reduction sites at two ends at a high speed to drive water to crack to generate hydrogen, and holes migrate to the oxidation sites synchronously to catalyze benzyl alcohol to be oxidized into benzaldehyde with high selectivity. The synergistic coupling of hydrogen production and organic oxidation can obviously inhibit electron-hole recombination and output two high-value products at the same time. Experimental results show that the hydrogen production rate and the benzaldehyde production rate of the CdS-MoS 2 -CoS space separation catalyst are respectively improved by 116 times and 22.8 times compared with the original CdS rod, and the efficient separation and full utilization of the photo-generated carriers are fully verified.

Inventors

  • ZHANG JING
  • WU HAO
  • Du Yunze
  • PENG WEIJIE
  • LI XUEYING

Assignees

  • 南京理工大学

Dates

Publication Date
20260508
Application Date
20260327

Claims (10)

  1. 1. A photocatalyst, characterized in that it comprises: CdS rods; Metal sulfides loaded at two ends of the CdS rod, wherein the metal sulfides are selected from one or more of Ag 2 S、MoS 2 and Ag ZnS, niS, cuS, coS, feS, mnS; CoS supported on the CdS rods.
  2. 2. The photocatalyst of claim 1, wherein the CdS rods have a rod length of 300 nm to 2000 nm.
  3. 3. The photocatalyst of claim 1, wherein the metal sulfide is supported at both ends of the CdS rod from the end point to 100 nm to 200 nm.
  4. 4. A method for preparing a photocatalyst according to any one of claims 1 to 3, comprising the steps of: S1) carrying out solvothermal reaction on a CdS rod, diethylenetriamine, acetylacetone metal salt and thioacetamide in water, and roasting the obtained product, wherein the acetylacetone metal salt is selected from one of silver acetylacetonate, molybdenum acetylacetonate, zinc acetylacetonate, nickel acetylacetonate, copper acetylacetonate, cobalt acetylacetonate, iron acetylacetonate and manganese acetylacetonate; S2) carrying out photo-deposition treatment on the product obtained in the step S1) in an aqueous solution of CoCl 2 , methanol and lactic acid to obtain the photocatalyst.
  5. 5. The method according to claim 4, wherein in the step S1), the CdS rod is obtained by reacting 0.5 mmol~0.6 mmol cadmium acetate, 0.05 g-0.15 g thioacetamide and 10 mL-30 mL ethylenediamine.
  6. 6. The method according to claim 4, wherein in the step S1), the amount of diethylenetriamine is 10 mL-25 mL, the amount of water is 1 mL-10 mL, the amount of acetylacetone metal salt is 0.05 mmol~0.15 mmol, and the amount of thioacetamide is 0.25 mmol~2.5 mmol.
  7. 7. The method according to claim 4, wherein in the step S2), the amount of methanol is 0.8 mL-1.2 mL, the amount of lactic acid is 0.8 mL-1.2 mL, and the concentration of CoCl 2 is 0.2 mg/mL-0.5 mg/mL.
  8. 8. The preparation method according to claim 4, wherein in the step S1), the temperature of the solvothermal reaction is 170-220 ℃, and the time of the solvothermal reaction is 16-20 hours; The CdS rod is obtained by carrying out solvothermal reaction on cadmium acetate, thioacetamide and ethylenediamine, wherein the solvothermal reaction temperature is 170-220 ℃, and the solvothermal reaction time is 16-20 hours; The roasting temperature is 300-500 ℃, and the roasting time is 1-3 hours; in the step S2), the time of the photo-deposition treatment is 0.5-3 h.
  9. 9. Use of a photocatalyst according to any one of claims 1 to 3 or a photocatalyst obtained by the preparation method according to any one of claims 4 to 8 in a selective organic oxidative coupling hydrogen production reaction.
  10. 10. The method for producing hydrogen by selective benzyl alcohol oxidative coupling is characterized by comprising the following steps: Under the condition of a photocatalyst, carrying out illumination on an aqueous solution containing benzyl alcohol; The photocatalyst is selected from the photocatalyst in any one of claims 1-3 or the photocatalyst obtained by the preparation method in any one of claims 4-8.

Description

Photocatalyst, and preparation method and application thereof Technical Field The invention relates to the field of photocatalysis, in particular to the field of hydrogen production by selective oxidative coupling of organic matters, and specifically relates to a photocatalyst, a preparation method and application thereof. Background Solar photocatalytic technology has received much attention in the face of increasingly stringent energy and environmental challenges due to its ability to directly convert light energy into chemical energy. However, this technique has long been limited to rapid recombination of photogenerated electron-hole pairs, severely limiting energy conversion efficiency. The existing sacrificial agent method can promote partial charge separation, but nearly half of photo-generated carriers are wasted, and the method has the defects in energy and economy. Therefore, development of a catalytic system capable of simultaneously utilizing photogenerated electrons and holes and synergistically driving oxidation and reduction half reactions has become an important research direction in the field. Among the many photocatalytic materials, cadmium sulfide (CdS) has good potential in visible light catalytic hydrogen production and organic conversion due to its narrow bandgap (about 2.4 eV) and suitable energy band structure. However, a single CdS material still has the problems of low carrier separation efficiency, poor stability, and the like. In recent years, construction of a spatially separated oxidation/reduction site is an effective strategy for improving charge separation efficiency, but development of a CdS-based integrated catalytic system capable of simultaneously and efficiently driving hydrogen production reaction and benzyl alcohol selective oxidation and realizing full utilization of electrons and holes still faces important challenges. Disclosure of Invention In view of the above, the technical problem to be solved by the invention is to provide a photocatalyst, a preparation method and application thereof, and the photocatalyst provided by the invention has high photocatalytic activity and good effect of producing hydrogen and benzaldehyde by selective oxidative coupling of benzyl alcohol. The present invention provides a photocatalyst comprising: CdS rods; Metal sulfides loaded at two ends of the CdS rod, wherein the metal sulfides are selected from one or more of Ag 2S、MoS2 and Ag ZnS, niS, cuS, coS, feS, mnS; CoS loaded on the rod body except two ends of the CdS rod. The photocatalyst provided by the invention comprises a CdS rod which is used as a substrate. Preferably, the rod length of the CdS rod is 300 nm-2000 nm. The photocatalyst provided by the invention further comprises metal sulfides loaded at two ends of the CdS rod, wherein the metal sulfides play a role of a reduction promoter, and the metal sulfides are loaded at two ends of the CdS rod from the end point to 100 nm-200 nm. The photocatalyst provided by the invention further comprises CoS loaded on the CdS rod body, wherein the CoS plays a role of an oxidation promoter. Specifically, the CoS is supported on a rod body other than the ends of the CdS rod on which the metal sulfide is supported. The photocatalyst provided by the invention is used as a CdS-based photocatalytic system with spatially separated oxidation/reduction sites, the system takes a CdS rod as a substrate, metal sulfides are loaded at two ends of the CdS rod as reduction promoters to construct reduction sites, and CoS is loaded on the surface of the rod as an oxidation promoter to construct oxidation sites. Through the cooperation of the space separation and the reaction of the oxidation site and the reduction site, the efficient separation and the full utilization of the photo-generated electron-hole pair are realized, and the overall efficiency and the atomic economy of the photo-catalytic process are remarkably improved. The invention also provides a preparation method of the photocatalyst, which comprises the following steps: S1) carrying out solvothermal reaction on a CdS rod, diethylenetriamine, acetylacetone metal salt and thioacetamide in water, and roasting the obtained product, wherein the acetylacetone metal salt is selected from one of silver acetylacetonate, molybdenum acetylacetonate, zinc acetylacetonate, nickel acetylacetonate, copper acetylacetonate, cobalt acetylacetonate, iron acetylacetonate and manganese acetylacetonate; S2) carrying out photo-deposition treatment on the product obtained in the step S1) in an aqueous solution of CoCl 2, methanol and lactic acid to obtain the photocatalyst. The invention firstly carries out solvothermal reaction of CdS rod, diethylenetriamine, acetylacetone metal salt and thioacetamide in water. Specifically, a CdS rod was added to diethylenetriamine and water, then, acetylacetone metal salt and thioacetamide were added thereto, and solvothermal reaction was performed with stirring. The dosage of