Study On Photocorrosion Inhibition Of Catalyst In Photocatalytic H₂ Evolution

Using sunlight energy to decompose water directly to produce hydrogen is of great significance in alleviating energy crisis.However,in the reaction process,the photocorrosion phenomenon will inevitably occur to the catalytic materials,which will affect the catalytic performance.Therefore,the exploration of photocorrosion mechanism has attracted the attention of many researchers.In this paper,the stability of the catalyst in photocatalytic H₂ evolution reaction was improved by two strategies,one is to fill the hole with cocatalyst and the other is to capture the hole with carrier.We use Ti O₂ and Cd S as model catalysts to thoroughly investigate the factors that affect their photostability.The use of cocatalysts,redox carrier modification,and heterogeneous structure construction can effectively inhibit the oxidation reaction of photo-generated holes with the catalyst to Improve the stability of the catalyst.At the same time,we explore and propose possible photo-corrosion inhibition mechanisms.The development of this research work provides theoretical guidance and new ideas for improving the photostability of catalysts.The specific research contents are as follows:（1）Using the method of photodeposition,Pt-Ti O₂ catalyst was prepared by photoreduction of Pt source with different electrical properties onto Ti O₂,and the influence mechanism of the electrical properties of Pt source on the stability of catalyst in the photocatalytic H₂ evolution reaction was explored.he results show that when the auxiliary platinum source(Pt Cl₆^2-)is egatively charged,the stability of Ti O₂ can be effectively improved.The chanism of the reaction was revealed by a series of characterization echniques.XRD,BET,ICP and TEM analysis showed that there was no ignificant difference in grain size,specific surface area and Pt content of the atalysts.However,the XPS spectra showed that the oxygen defect was the ost in the Ti O₂ after the reaction,while the oxygen defect in Pt-Ti O₂ was ignificantly reduced after the addition of negative charged cocatalyst Pt ource(Pt Cl₆^2-).At the same time,compared with other Pt cocatalysts,Raman ignal blue shift of Pt Cl₆^2-cocatalysts is smaller,indicating that electrostatic ttraction effect promotes Pt Cl₆^2-to occupy and repair the oxygen defect in t-Ti O₂ to the maximum extent.In this work,the bulk phase oxygen defects aused by photocorrosion of Ti O₂ in the reaction process were filled by the ddition of different electrical Pt cocatalysts,thus improving the stability of t-Ti O₂ catalyst,establishing the relationship between stability and electrical roperties of cocatalysts,oxygen defects,and providing a theoretical basis or the design of high stability of Ti-based photocatalyst.（2）Cd S quantum dots were successfully synthesized by thermal injection,and hen loaded on the surface of Ce O₂ with different crystal surfaces.The ctivity and stability of photocatalytic H₂ evolution reaction showed that d S/Ce O₂{110}had the best performance,followed by Cd S/Ce O₂{100},and d S/Ce O₂{111}had the worst performance.Through a series of haracterization techniques,we revealed the root cause of the difference in eaction performance.It was found that due to the interfacial electron nteraction,the Cd S valence band holes in Cd S/Ce O₂{110}catalyst would ransfer to the surface of Ce O₂,and the Ce³⁺/Ce⁴⁺REDOX charge in Ce O₂ ould use up the holes,thus inhibiting the corrosion of Cd S.In addition, nder the action of an internal electric field,Cd S/Ce O₂{110}forms a Z- cheme heterojunction,which kinetically promotes the reduction of water to H₂.In this work,the support Ce O₂{110}is used to transfer and consume the photogenerated holes,so as to inhibit the photocorrosion of Cd S and improve the stability of the photocatalyst.