Regulating Cu Oxidation State for Electrocatalytic CO<sub>2</sub> Conversion into CO with Near‐Unity Selectivity via Oxygen Spillover
Yufei Jia, Dekang Li, Chang Liu, Tao Song, Lele Duan, Fusheng Li, Fei Li, Yongfei Ji, Licheng Sun, Ke Fan
Abstract
Abstract Cu‐based catalysts are the most intensively studied in the field of electrocatalytic CO 2 reduction reaction (CO 2 RR), demonstrating the capacity to yield diverse C 1 and C 2+ products albeit with unsatisfactory selectivity. Manipulation of the oxidation state of Cu sites during CO 2 RR process proves advantageous in modulating the selectivity of productions, but poses a formidable challenge. Here, an oxygen spillover strategy is proposed to enhance the oxidation state of Cu during CO 2 RR by incorporating the oxygen donor Sb 2 O 4 . The Cu‐Sb bimetallic oxide catalyst attains a remarkable CO 2 ‐to‐CO selectivity approaching unity, in stark contrast to the diverse product distribution observed with bare CuO. The exceptional Faradaic efficiency of CO can be maintained across a wide range of potential windows of ≈700 mV in 1 m KOH, and remains independent of the Cu/Sb ratio (ranging from 0.1:1 to 10:1). Correlative calculations and experimental results reveal that oxygen spillover from Sb 2 O 4 to Cu sites maintains the relatively high valence state of Cu during CO 2 RR, which diminishes the binding strength of * CO, thereby achieving heightened selectivity in CO production. These findings propose the role of oxygen spillover in CO 2 RR over Cu‐based catalysts, and shed light on the rational design of highly selective CO 2 reduction catalysts.