Flexible Cuprous Triazolate Frameworks as Highly Stable and Efficient Electrocatalysts for CO2 Reduction with Tunable C2H4/CH4 Selectivity

Abstract Cu‐based metal–organic frameworks have attracted much attention for electrocatalytic CO 2 reduction, but they are generally instable and difficult to control the product selectivity. We report flexible Cu(I) triazolate frameworks as efficient, stable, and tunable electrocatalysts for CO 2 reduction to C 2 H 4 /CH 4 . By changing the size of ligand side groups, the C 2 H 4 /CH 4 selectivity ratio can be gradually tuned and inversed from 11.8 : 1 to 1 : 2.6, giving C 2 H 4 , CH 4 , and hydrocarbon selectivities up to 51 %, 56 %, and 77 %, respectively. After long‐term electrocatalysis, they can retain the structures/morphologies without formation of Cu‐based inorganic species. Computational simulations showed that the coordination geometry of Cu(I) changed from triangular to tetrahedral to bind the reaction intermediates, and two adjacent Cu(I) cooperated for C−C coupling to form C 2 H 4 . Importantly, the ligand side groups controlled the catalyst flexibility by the steric hindrance mechanism, and the C 2 H 4 pathway is more sensitive than the CH 4 one.