Preparation Of Ultra-Low Content Pt/Sulfide Composite And Its Efficient Application In Alcohol Oxidation-Hydrogen Production

Photocatalytic selective conversion of benzyl alcohol to benzaldehyde and photocatalytic hydrogen production are the research hotspots in the field of photocatalysis,which are of great significance to alleviate the current energy and environmental problems.By analyzing the latest research progress of CdS semiconductor catalysts,it can be found that doping and controlling its band gap structure,constructing heterostructure and loading cocatalyst can improve the photocatalytic performance of CdS to a certain extent.In this work,in order to reduce the use cost and ensure the tight combination of cocatalyst and main catalyst（sulfide）,a series of Pt/sulfide photocatalysts were prepared by anchoring ultra-low content of pre-prepared Ptnanoparticles（PtNPs）to sulfide in the process of sulfide preparation,and they were applied to the coupling reaction system of selective oxidation of aromatic alcohol to produce H₂ and aromatic aldehyde under visible light irradiation.The main work includes the following two parts:（1）Pt/CdS catalyst deposited with ultra-low content of Pt:firstly,3-4 nm PtNPs solution was prepared by hydrothermal method with reference to relevant literature,and then different amounts of pre-prepared PtNPs solution were introduced in the process of preparing CdS by solvothermal method,thus preparing Pt/CdS catalyst supported with ultra-low content of Pt.The characterization results show that PtNPs is firmly anchored on the surface of CdSNRs;In the coupling reaction of photocatalytic selective oxidation of aromatic alcohol to produce H₂ and aromatic aldehyde,Pt/CdS catalysts showed excellent photocatalytic activity,especially the hydrogen production of 0.045%-Pt/CdS in 4 h was as high as 1.921 mmol,which was 209 times that of monomer CdS.Based on the results of physical and chemical characterization,the reaction mechanism of the coupling system was proposed.By optimizing the preparation parameters and constructing the coupling reaction system,this work successfully achieved the goal of reducing the reaction cost and making full use of photo-generated charges,which will provide a very valuable reference for the study of photocatalytic oxidation of alcohol and hydrogen production in the same system.（2）Pt/CdLa₂S₄ catalysts deposited with ultra-low content of Pt:In order to further expand the range of catalysts that can be used in the coupling reaction system in（1）,according to the same preparation strategy in（1）,pre-prepared PtNPs was introduced in the process of preparing CdLa₂S₄,so as to obtain Pt/CdLa₂S₄ catalysts with different Ptcontents（all with ultra-low content）;Then,it was used for photocatalytic study of selective oxidation of aromatic alcohols to produce corresponding aromatic aldehydes under visible light radiation.The results show that0.057%-Pt/CdLa₂S₄ has the best photocatalytic activity for hydrogen production and alcohol oxidation.The morphology,adsorption performance,microstructure,charge distribution and reaction species of each catalyst were comprehensively analyzed by physical and chemical means,and the catalytic mechanism of the coupling reaction system was proposed based on this.This work successfully expanded the types of catalysts suitable for this coupling system,and realized the full utilization of photoinduced charges.