Highly‐Exposed Single‐Interlayered Cu Edges Enable High‐Rate CO2‐to‐CH4 Electrosynthesis

The electrochemical CO2 reduction to CH4 is a promising approach for producing highly specific combustion fuel but has relatively poor selectivity and activity at high‐current‐density electrolysis. In this work, ultrathin CuGaO2 nanosheets with highly exposed single‐interlayered Cu edges are synthesized via an induced anisotropic growth strategy. Density functional theory calculations indicate that the exposed single‐interlayered Cu(I) edges on the (001) surface of CuGaO2 present a high‐density of single‐atomic Cu sites, which feature excellent CO2 electroreduction catalytic activity toward CH4. The CuGaO2 nanosheet catalysts exhibit efficient and stable CO2‐to‐CH4 electroreduction with Faradaic efficiency (FECH4) of 71.7% at a high current density of –1 A cm−2, corresponding to a superior CH4 partial current density of 717 ± 33 mA cm−2. This work suggests an attractive design strategy for tuning both the crystal facets and Cu–Cu distance to promote the CH4 electrosynthesis at high‐current‐density CO2 reduction. The electrochemical CO2‐to‐CH4 conversion has relatively poor selectivity at high‐current‐density electrolysis. The ultrathin CuGaO2 nanosheet catalyst features high‐density, single‐interlayered Cu edges and larger Cu–Cu distances, exhibiting an exceptional jCH4 of 717 ± 33 mA cm−2 with FECH4 of 71.7%, and an outstanding stability at a high current density of –1 A cm−2 in flow cells.