Inorganic-Organic Sites Synergy in Trinuclear Metal-Cluster-based COFs for Highly Selective CO2 Electroreduction

Metal-based covalent organic frameworks (COFs) have recently emerged as promising heterogeneous electrocatalysts for CO2 reduction, yet achieving molecular-level control over product selectivity remains challenging. To address this limitation, we report the synthesis of two trinuclear metal-cluster-based mesoporous COFs-AgTrzPh and CuTrzPh prepared under ambient and scalable reaction conditions. These materials represent the first examples of COFs in-corporating atomically precise trinuclear metal cluster nodes. Notably, the two frameworks exhibit distinct CO2 elec-troreduction behaviors dictated by the intrinsic electronic characteristics of their metal centers. AgTrzPh achieves ex-ceptionally high CO selectivity (92%), whereas CuTrzPh generates a mixed product distribution with 41% CO and 35% HCOOH, marking the highest CO and HCOOH selectivity reported to date for pristine COF catalysts. The superior catalytic response originates from the synergistic interplay between the inorganic metal-cluster nodes and the imine-linked organic framework, where both contribute as active sites while supporting extended π-electron transport. Complementary theoretical investigations corroborate the experimental observations, revealing energetically favora-ble pathways and identifying dual catalytic sites responsible for controlling product formation. Overall, this work demonstrates a strong structure–activity relationship and highlights metal-cluster-integrated COFs as a highly tuna-ble platform for selective CO₂ electroreduction.