Photoinduced Preparation Of Bimetallic Dimers And Photocatalytic Properties

With the further development of industrialization and the continuous increase of the global population,human society is facing the increasingly serious crisis of resource depletion and environmental degradation.Therefore,how to improve the efficient use of energy has become a key issue to solve the current energy crisis.Studies have shown that efficient diatomic catalysts play a very important role in energy conversion.Compared with single-atom catalysts（SACs）,diatomic catalysts（DACs）can not only increase the atomic loading,but also enhance the interaction between the metal and the support,which effectively avoids the agglomeration problem in the process of synthesis and application.At the same time,the introduction of another homonuclear or heteronuclear atom promotes DACs to have adjacent active sites,and the synergistic effect between the adjacent active sites can significantly improve their catalytic activity and have good catalytic selectivity.But the precise synthesis of diatomic catalysts remains a great challenge,especially for heteronuclear diatomic dimers.Based on this,this paper mainly carries out the following research work:（1）We propose a“navigation and positioning”strategy to anchor bimetallic dimers on photosensitive polymeric carbon nitride（PCN）through a two-step process.The first is the large-scale fabrication of Zn single atoms by direct calcination of urea and Zn（OOCCH₃）₂ to create appropriate nucleation sites on PCNs that can navigate and attach secondary metal centers,through a photo-induced process,thereby DACs Ru Zn-PCN were generated.Systematic studies show that the generation of nucleation sites can tune the electronic structure of PCNs to recognize secondary metals to form dimers with an atomic spacing of about 2.5?.The d-orbital hybridization of Ru and Zn mainly contributes to the construction of an empty band to facilitate photogenerated electron transfer.The Zn and Ru centers were identified as H*absorption sites and catalytically active centers,respectively,and their synergistic effect could significantly enhance the hydrogen evolution activity.This work highlights a promising general strategy for the rational design of bimetallic dimers via a photo-induced charge compensation process.（2）We continue to explore the synthesis of other bimetallic dimers by adopting the"navigation and positioning"strategy,generalize the generality of this strategy,and initially explore the catalytic properties.On the basis of Ru Zn-PCN,we continued to synthesize Cu Bi-PCN,Cu Zn-PCN and Ru Bi-PCN,and initially explored their application in photocatalytic cracking of lignin.