Steering CO<sub>2</sub> Electroreduction Selectivity U-Turn to Ethylene by Cu–Si Bonded Interface
Wanfeng Xiong, Duan‐Hui Si, Hong-Fang Li, Xianmeng Song, Tao Wang, Yuan‐Biao Huang, Tian‐Fu Liu, Teng Zhang, Rong Cao
Abstract
Copper (Cu), with the advantage of producing a deep reduction product, is a unique catalyst for the electrochemical reduction of CO 2 (CO 2 RR). Designing a Cu-based catalyst to trigger CO 2 RR to a multicarbon product and understanding the accurate structure–activity relationship for elucidating reaction mechanisms still remain a challenge. Herein, we demonstrate a rational design of a core–shell structured silica-copper catalyst (p-Cu@m-SiO 2 ) through Cu–Si direct bonding for efficient and selective CO 2 RR. The Cu–Si interface fulfills the inversion in CO 2 RR product selectivity. The product ratio of C 2 H 4 /CH 4 changes from 0.6 to 14.4 after silica modification, and the current density reaches a high of up to 450 mA cm –2 . The kinetic isotopic effect, in situ attenuated total reflection Fourier-transform infrared spectra, and density functional theory were applied to elucidate the reaction mechanism. The SiO 2 shell stabilizes the *H intermediate by forming Si–O–H and inhibits the hydrogen evolution reaction effectively. Moreover, the direct-bonded Cu–Si interface makes bare Cu sites with larger charge density. Such bare Cu sites and Si–O–H sites stabilized the *CHO and activated the *CO, promoting the coupling of *CHO and *CO intermediates to form C 2 H 4 . This work provides a promising strategy for designing Cu-based catalysts with high C 2 H 4 catalytic activity.