Atomic‐Level Elucidation of Lattice‐Hydrogens in Copper Catalysts for Selective CO <sub>2</sub> Electrochemical Conversion toward C <sub>2</sub> Products
Xiaoshuang Ma, Cong Fang, Mei Ding, Yang Zuo, Xiaoyan Sun, Shuxin Wang
Abstract
Abstract Copper is the most efficient and practical electrocatalyst for the electrochemical reduction of carbon dioxide (ECR) to give multicarbon (C 2+ ) products, but the mechanism by which such products are formed – though known to involve lattice‐hydrogens – remains elusive, and the selectivity of the reaction is poor. Herein, we report the synthesis of [AuCu 24 (dppp) 6 H 22 ] + , a copper hydride nanocluster bearing exposed Cu 3 H 3 units in specific surface cavities, and our use of it to study the mechansim and selectivity of the reduction of CO 2 to C 2+ products. Results of in situ infrared spectroscopy and theoretical calculations showed that these Cu 3 H 3 units can effectively lower the energy barrier to the formation of the *COCOH intermediate, which allowed the competition between the C 1 and C 2 pathways to be elucidated. Isotope labeling experiments and catalyst recrystallization studies corroborated the theoretical simulations, identifying the lattice‐hydrogen (H − ) in the Cu 3 H 3 active unit as being indispensable for the formation of C 2 H 4 . The molecular design guidelines which this work has facilitated constitute a new approach towards the of copper‐based catalysts that convert CO 2 to C 2+ products based on lattice‐hydrogen engineering.