Switching CO2 Electroreduction toward C2+ Products and CH4 by Regulate the Protonation and Dimerization in Platinum/Copper Catalysts

Copper (Cu)‐based catalysts exhibit distinctive performance in the electrochemical CO2 reduction reaction (CO2RR) with complex mechanism and sophisticated types of products. The management of key intermediates *CO and *H is a necessary factor for achieving high product selectivity, but lack of efficient and versatile strategies. Herein, we designed Pt modified Cu catalysts to effectively modulate the competitive coverage of those intermediates. The Pt single‐atoms and Pt nanoparticles modified Cu catalysts (denoted as Cu‐Pt1 and Cu‐PtNPs) precisely regulated the protonation and dimerization, with the faradaic efficiency (FE) of C2+ products up to 70.4% and the FE of CH4 reaching 57.7%, respectively. CO stripping experiments reveal that Pt1 sites could enhance the adsorption of *CO, while PtNPs exhibit *CO tolerance for H2O dissociation. In situ spectroscopic results further confirms that high coverage of *CO is achieved on Cu‐Pt1, while *CHO on Cu‐PtNPs might generate by additional water dissociation. As elucidated by theoretical studies, the interfacial sites of Cu‐Pt1 would favor the *CO coverage promoting the evolution of *OCCO for C2+ products while PtNPs supplementarily accelerate H2O dissociation achieving *CHO for CH4. This work provides insights for efficient and targeted CO2 conversion by atomically design of active sites with engineered key intermediates coverage.