Homogeneous Vacancies-Enhanced Orbital Hybridization for Selective and Efficient CO<sub>2</sub>-to-CO Electrocatalysis.

Qin, Yuntong; Zhan, Guangming; Tang, Cun; Yang, Di; Wang, Xibo; Yang, Jianhua; Mao, Chengliang; Hao, Zhentian et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

Crafting vacancies offers an efficient route to upgrade the selectivity and productivity of nanomaterials for CO<sub>2</sub> electroreduction. However, defective nanoelectrocatalysts bear catalytically active vacancies mostly on their surface, with the rest of the interior atoms adiaphorous for CO<sub>2</sub>-to-product conversion. Herein, taking nanosilver as a prototype, we arouse the catalytic ability of internal atoms by creating homogeneous vacancies realized via electrochemical reconstruction of silver halides. The homogeneous vacancies-rich nanosilver, compared to the surface vacancies-dominated counterpart, features a more positive d-band center to trigger an intensified hybridization of the Ag_d orbital with the C_P orbital of the *COOH intermediate, leading to an accelerated CO<sub>2</sub>-to-CO transformation. These structural and electronic merits allow a large-area (9 cm<sup>-2</sup>) electrode to generate nearly pure CO with a CO/H<sub>2</sub> Faradaic efficiency ratio of 6932 at an applied current of 7.5 A. These findings highlight the potential of designing new-type defects in realizing the industrialization of electrocatalytic CO<sub>2</sub> reduction.