Switching CO₂ Electroreduction toward C₂₊ Products and CH₄ by Regulating the Dimerization and Protonation 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-Pt_NPs) 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 Pt_NPs 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-Pt_NPs 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 Pt_NPs 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.