Potential-dependent C–C coupling mechanism and activity of C₂ formation in the electrocatalytic reduction of CO₂ on defective Cu(100) surfaces

The potential-dependent C–C coupling mechanism for C₂ formation in the electrocatalytic reduction of CO₂ is studied on several defective Cu(100) surfaces, and a nonmonotonic trend is observed between the effective free energy barriers and the average coordination numbers. Further structural analysis reveals that Cu surface strain along the parallel and vertical directions with respect to the C–C bond would have distinct impacts on the modulation of the barriers.