Constructing Metal-Semiconductor Heterojunction-based Catalysts To Promote Photocatalytic Organic Syntheses

Semiconductor photocatalysis can easily convert light energy into chemical energy,which become the most promising research direction.And more importantly the word-wide energy crisis and environmental deterioration can be addressed simultaneously by this way.In the conventional photocatalysis research,we excessively focused on the water splitting reaction and the C02 photoreduction research but neglected that the nature of photocatalysis is to convert light energy.For this reason,the photocatalysis organic synthesis,which have a broader potential to realize various forms of energy convert,came into our sight.However,there are still problems such as weak response to the visible light and poor separating efficiency of photo-induced carries in photocatalysis.After years of research,scientists have identified a number of ways to dealt with these problems such as element doping,controling the expose of specific facets and building heterojunction.But most of these did not have more comprehensive solution to resolve the problem of photocatalysis.The Schottky junction between metal co-catalysts and semiconductor photocatalysts is known to be in favor of the separation of photogenerated charge carriers.In addition,metal co-catalysts have plenty of active sites in organic reactions.For these reasons,the metal-semiconductor heterojunction catalysts are suit for the photocatalysis organic synthesis reaction.Moreover,some metals such as copper(Cu),silver(Ag),and gold(Au)show strong photoabsorption of visible light due to surface plasmon resonance that can play a photosensitization role on semiconductor photocatalysis.Given the above,we decide to build metal-semiconductor heterojunction catalysts to realize efficient organic synthesis reaction of photocatalysis.The main contents are summarized as following:1.we successfully fabricated Ag-nanocube@Cu20 core-shell heterostructure catalysts to study the characteristics of photo-assist propylene oxidation reaction.Strikingly,shell of Cu20 suppress the reaction of excessive oxidation and protect the state of Ag nanocubes.More interestingly,such unique Ag-nanocube@Cu20 heterostructure can make effectively use of light energy to promote efficiency of the reaction.2.Commercial titania powders,P25 as a carrier to loaded Au,Pd,Pt and Au-Pd alloy are used for H2 production via reforming of methanol.Through the comparison and analysis,we can find our catalyst which have 3 wt%loading amount and reacting in 80%methanol solution reach the highest efficiency of hydrogen-producing as ever reported.Meanwhile,we presented the effect mechanisms of water by modifying the reaction conditions and Combining with document reports.