Hybrid Catalyst Coupling Single-Atom Ni and Nanoscale Cu for Efficient CO₂ Electroreduction to Ethylene

Abstract

A hybrid catalyst with integrated single-atom Ni and nanoscale Cu catalytic components is reported to enhance the C-C coupling and ethylene (C₂H₄) production efficiency in the electrocatalytic CO₂ reduction reaction (eCO₂RR). The single-atom Ni anchored on high-surface-area ordered mesoporous carbon enables high-rate and selective conversion of CO₂ to CO in a wide potential range, which complements the subsequent CO enrichment on Cu nanowires (NWs) for the C-C coupling to C₂H₄. In situ surface-enhanced infrared absorption spectroscopy (SEIRAS) confirms the substantially improved CO enrichment on Cu, once the incorporation of single-atom Ni occurs. Also, in situ X-ray absorption near-edge structure (XANES) demonstrates the structural stability of the hybrid catalyst during eCO₂RR. By modulating hybrid compositions, the optimized catalyst shows 66% Faradaic efficiency (FE) in an alkaline flow cell with over 100 mA·cm^-2 at -0.5 V versus reversible hydrogen electrode, leading to a five-order enhancement in C₂H₄ selectivity compared with single-component Cu NWs.