CuGa Alloy Anchored on Nitrogen-Doped Carbon for Electrocatalytic CO2 Reduction into Multicarbon Products

Abstract

Electrochemical CO2 reduction to multicarbon (C2+) products remains challenging due to the involvement of numerous proton-coupled electron transfer processes. Herein, a series of composite catalysts were designed by anchoring Cu(Ga) solid solution alloy onto nitrogen-doped carbon (N–C) matrix derived from chitosan, where the former tunes the electronic structure for optimized intermediates adsorption, and the latter enhances metal dispersion and facilitates CO2 enrichment/activation. The optimized Cu3Ga1/N–C catalyst achieved a high Faradaic efficiency of 75.21% for C2+ products at a low potential of –1.7 V vs. Hg/HgO (approximately –0.77 V vs RHE). Its catalytic activity and structural integrity showed no obvious degradation over 12 h of continuous electrolysis at ∼110 mA cm–2. Control experiments demonstrate that the N–C support plays an indispensable role in enhancing the selectivity of Cu(Ga) alloys towards C2+ products at lower overpotentials. While validating that the N–C support facilitates CO2 activation, DFT calculations revealed that alloying regulates the electronic structure through p-d orbital hybridization between Cu and Ga, stabilizing *CO intermediates and thereby reducing the kinetic barriers of the rate-determining *CO dimerization step. This work provides a viable design reference for developing efficient and durable composite catalysts for value-added CO2 conversion.