摘要
Electrochemical CO 2 reduction (ECR) is a potential route for establishing a carbon–neutral economy. Despite notable breakthroughs, designing a catalytic system with desired product selectivity remains a formidable challenge. Herein, we demonstrate a novel nanoarchitecture comprising sub-nanometer In 2 O 3 clusters on Ag nanoparticles (henceforth denoted as Ag 2 -In 8 /C) for highly selective formate (HCOOH) production in ECR. As-prepared Ag 2 -In 8 /C NC with the Ag/In atomic ratio of 2/8 achieved the formate faradaic efficiency (FE HCOOH ) of as high as 95.5 % at −0.9 V RHE with no obvious degradation after 7 h, surpassing the monometallic counterparts (Ag/C and In 2 O 3 /C) in selectivity and activity. The in-situ X-ray absorption spectroscopy reveals the formation of sub-nanometer In 2 O clusters (i.e. Indium changed its phase from In 2 O 3 to In 2 O) on Ag nanoparticles under potential-driven conditions, where the high activity and selectivity of Ag 2 -In 8 /C NC originates from the robust synergistic cooperation between Ag and In 2 O domains at the Ag-In 2 O interface, underscoring its role as the active site for highly selective ECR. Moreover, an amalgamation of the physical and electrochemical analysis suggests that In 2 O clusters assist *OCHO formation on the surface of Ag 2 -In 8 /C NC during ECR and thus pronounced formate selectivity is achieved. In light of our findings, this study promises to unravel intricate mechanistic insights, thus paving the way for the rational design of exceptionally selective catalysts for ECR.