Regulating Spin Density using TEMPOL Molecules for Enhanced CO<sub>2</sub>‐to‐Ethylene Conversion by HKUST‐1 Framework Derived Electrocatalysts
Baipeng Yin, Can Wang, Shijie Xie, Jianmin Gu, Hua Sheng, De‐Xian Wang, Jiannian Yao, Chuang Zhang
Abstract
Abstract The selectivity of multicarbon products in the CO 2 reduction reaction (CO 2 RR) depends on the spin alignment of neighboring active sites, which requires a spin catalyst that facilitates electron transfer with antiparallel spins for enhanced C−C coupling. Here, we design a radical‐contained spin catalyst (TEMPOL@HKUST‐1) to enhance CO 2 ‐to‐ethylene conversion, in which spin‐disordered (SDO) and spin‐ordered (SO) phases co‐exist to construct an asymmetric spin configuration of neighboring active sites. The replacement of axially coordinated H 2 O molecules with TEMPOL radicals introduces spin‐spin interactions among the Cu(II) centers to form localized SO phases within the original H 2 O‐mediated SDO phases. Therefore, TEMPOL@HKUST‐1 derived catalyst exhibited an approximately two‐fold enhancement in ethylene selectivity during the CO 2 RR at −1.8 V versus Ag/AgCl compared to pristine HKUST‐1. In situ ATR‐SEIRAS spectra indicate that the spin configuration at asymmetric SO/SDO sites significantly reduces the kinetic barrier for *CO intermediate dimerization toward the ethylene product. The performance of the spin catalyst is further improved by spin alignment under a magnetic field, resulting in a maximum ethylene selectivity of more than 50 %. The exploration of the spin‐polarized kinetics of the CO 2 RR provides a promising path for the development of novel spin electrocatalysts with superior performance.