Scalable preparation of a CuO nanosheet array via corrosion engineering for selective C–C coupling in CO2 electroreduction

Abstract

So far, copper (Cu) has been the only monometallic catalyst with substantial selectivity and productivity for the electrochemical CO₂ reduction reaction (ECO₂RR) to produce C₂₊ products. However, there still remains an enormous challenge to prepare highly efficient Cu electrodes on a large scale for industrial application. Additionally, further understanding of the structure–activity relationship of electrodes used in the ECO₂RR is significantly important but lacking for the design of efficient Cu electrodes. Herein, we report a scalable preparation of a CuO nanosheet array on a Cu substrate via a facile corrosion engineering strategy. By tuning the surface roughness via controlling the corrosion time, we achieved a high faradaic efficiency (FE) for C₂₊ products (63.93% in an H-type cell, 70% in a flow cell) in the ECO₂RR. In addition, the electrode showed a high selectivity exceeding 80% for C₂₊ products toward the electrochemical CO reduction reaction (ECORR). Moreover, we elucidate the structure–activity relationship of the CO₂RR electrodes using our electrodes as a model, where both high active site density and moderate surface roughness are required simultaneously for an efficient CO₂RR electrode, which would inspire future related studies.