Controllable Synthesis Of Single-atom,Cluster Catalysts And Activation Of Small Molecules

With the rapid development of science and technology,human living standard is improving significantly.However,the process of development requires more energy,and the phenomenon of energy shortage has aroused widespread concern around the world.Therefore,making full use of energy is the key to solving this problem.As we all know,catalysis plays an indispensable role in the effective use of energy,and the key to catalysis lies in the preparation of catalysts.At present,single-atom(SAs)and nanoclusters(NCs)catalysts have become frontiers and hotspots in the field of catalysis owing to their unique electronic structure and functional orientation.Therefore,precise synthesis of ultra-small metal catalysts with high-efficiency catalysis is an important challenge.This article mainly carried out the following research work.(1)Solar-driven high-efficiency and direct conversion of methane into high value-added liquid oxygenates against overoxidation remains chemically challenging.The facile and mass fabrication of low-cost tungsten single atom photocatalysts(SAPs)was achieved by calcining raw materials of urea and sodium tungstate under atmosphere to immobilize W centers into polymeric carbon nitride(W-SA-PCN).The SAPs can manage the in situ generation of H₂O₂ from H₂O and decomposition into·OH to avoid the overoxidation,thus achieving highly efficient and selective CH₄photooxidation with water vapour under mild conditions.Systematic investigations demonstrate that the integration of multifunctions of methane activation,H₂O₂generation and decomposition into one SAP can dramatically promote the methane conversion to C1 oxygenates with a yield of as high as 4956?mol·g^-1_cat,much superior to that of all the reported low-cost photocatalysts.This work highlights the possibility for high-efficiency and direct CH₄photooxidation under solar light with in situ H₂O₂ formation and decomposition to protect against overoxidation.(2)Ultrafine fcc Ru nanoclusters(NCs)are of great interest as their super high catalytic activity.However,it is extremely difficult to prepare 1 nm fcc Ru NCs with high energy atoms due to their easy aggregation.Herein,we first unveil the nucleation process of Ru centers by confined pyrolysis of a multivariate metal-organic framework to isolate ultrafine fcc NCs(from single atom to 1.33 nm)via in-situ formed stabilizers.Systematic investigations demonstrate that preferential nucleation of Ru single atoms to fcc clusters in the initial nucleation represents a key step and makes it possible to separate ultrafine fcc Ru NCs with in-situ formed N-doped porous carbon.A record high turnover frequency of 1300.53 min^-1 for methanolysis of ammonia borane was achieved by 1.33 nm NCs.This work suggests a new strategy to prepare ultrafine fcc Ru NCs.