Stabilized Cu δ+ -OH species on Cu nanoparticles encapsulated in porous carbon nitride for electrocatalytic reduction of CO 2 to ethylene

Abstract

Achieving large-scale electrochemical CO2 reduction to multicarbon products with high selectivity is promising for carbon neutrality. However, the unsatisfactory multicarbon products selectivity and unclear reaction mechanisms have hindered its further development. Herein, we report a strategy that manipulates the interfacial microenvironment of Cu nanoparticle (NP) by incorporation with g-C3N4 to realize the reduction products shift from methane to ethylene. In situ characterizations and theoretical calculations demonstrate that the formation of Cu-N bonds between Cu NP and porous g-C₃N₄ creates the Cu δ⁺ (0 < δ < 1) species. Such Cu δ⁺ sites enhanced *OH (derived from water dissociation) adsorption through the formation of Cu δ⁺ -OH intermediates. The stabilized Cu δ⁺ -OH species lower the energy barrier for the asymmetric coupling of *CO and *CHO intermediates, steering the reaction pathway from methane to ethylene. The as-prepared Cu/200-C₃N₄ catalyst exhibits an exceptional ethylene selectivity (57% ) even at a large current density of 600 mA• cm⁻² in the flow cell.This study advances our understanding of the CO2 reduction mechanism and offers an effective and general strategy for enhancing electrocatalytic performance by regulating water dissociation.