Efficient large-current conversion of CO2 to C2H5OH via a *CO-*OCH2 coupling pathway on alkanethiol-modified Cu2O array electrode

Developing advanced electrocatalysts to convert CO 2 into liquid fuels such as C 2 H 5 OH is critical for utilizing intermittent renewable energy. The formation of C 2 H 5 OH, however, is generally less favored compared with the other hydrocarbon products from Cu-based electrocatalysts. In this work, an alkanethiol-modified Cu₂O nanowire array (OTT-Cu₂O) was constructed with asymmetric Cu sites consisting of paired Cu–O and Cu–S motifs to overcome previous limitations of C 2 H 5 OH electrosynthesis via CO 2 RR pathway. This catalyst achieves a high Faradaic efficiency of 45% for CO 2 -to-C 2 H 5 OH conversion at 300 mA/cm 2 , representing a more than two-fold enhancement over the Cu 2 O electrode. Mechanistic investigations reveal that the Cu–S site exhibits distinct C-binding capability that stabilizes key intermediates (*OCH 2 and *CO), in contrast to the O-affinitive Cu–O site. The asymmetric S–Cu–O configuration promotes thermodynamically favorable asymmetric C–C coupling between *CO and *OCH 2 , forming the critical CO–OCH₂ intermediate and facilitating C 2 H 5 OH production, as opposed to symmetric O–Cu–O sites that mainly generate HCOOH. This work offers an effective strategy for designing multi-active-site catalysts toward highly selective CO₂ reduction to C 2 H 5 OH and provides fundamental insight into the reaction mechanism.