Organic frameworks confined Cu single atoms and nanoclusters for tandem electrocatalytic CO_(2) reduction to methane

The electrochemical reduction reaction of carbon dioxide(CO_(2)RR)is considered to be an effective way to realize carbon neutrality.As a type of intensively studied materials,covalent organic frameworks(COFs)with a tunable pore structure and various functional groups are promising catalysts for CO_(2)RR.Herein,COF synthesized by 2,6‐diaminoanthraquinone and 2,4,6‐triformylphloroglucinol is employed to assist the synthesis of electrocatalysts from Cu single atoms(SAs)to nanoclusters by controlling the electrodeposition.A tandem catalyst for CO_(2)‐to‐CH4 conversion is thus achieved by the Cu nanoclusters dispersed among the isolated Cu SAs in the COF network.It is proposed that CO_(2) is first reduced to CO over the atomically isolated Cu SAs,followed by diffusion onto the neighboring Cu nanoclusters for further reduction into CH4.In addition,mechanistic analysis suggests that the coordinated K^(+)ions on the COF network promote the activation of CO_(2) and the adsorption of reaction intermediates,thus realizing the suppressed hydrogen evolution reaction and selective production of CH4.This study presents a new insight of COFs for the confined synthesis of a tunable SA to nanocluster electrocatalysts,disclosing the great potential of COFs in electrocatalysis.