Confined Pyrolysis Within Metal-Organic Frameworks To Form Copper Atom-pair For Electrocatalytic Activation Of Small Molecules

The reduction of carbon dioxide or the conversion of carbon dioxide into high value-added chemicals is of great research significance.Transition metal single-atom catalysts have the advantages of high activity and high stability in the field of electrocatalytic carbon dioxide reduction,and have received extensive attention.However,for electrocatalytic carbon dioxide reduction reactions involving multiple intermediates and multiple products,the construction of a multi-atom synergistic catalyst is expected to further improve the catalytic efficiency.Based on the above ideas,we assembled Cu₂（ophen）₂ dinuclear molecules into MAF-6 cages,and then subjected to high temperature pyrolysis in Ar atmosphere to obtain diatomic Cu₂-NC（MAF-6）catalysts.It was observed by TEM that Cu elements were uniformly distributed on the carbon nitride substrate,and by HADDF-STEM,it was further observed that copper atoms existed in pairs and some clusters were also present.Using Cu₂-NC（MAF-6）as a catalyst,electrocatalytic carbon dioxide reduction showed that the Faraday efficiency of carbon dioxide conversion to carbon monoxide can reach 93%at an overpotential of 390 m V,and the catalyst has excellent stability.Oxygen reduction reactions occur in the cathodes of proton exchange membrane batteries and metal-air batteries,but problems such as complex paths and slow kinetics have affected their research progress.Therefore,the development of oxygen reduction catalysts with high activity and durability is a key step in the construction of proton exchange membrane batteries and metal-air batteries.We used the synthesized Cu2-NC（MAF-6）catalyst to conduct electrocatalytic oxygen reduction experiments.The experimental results show that Cu2-NC（MAF-6）has excellent electrocatalytic oxygen reduction performance.The half-wave potential of the catalyst can reach 0.85V in 0.1 M KOH solution,and the catalyst has good methanol resistance and stability.