Twin Heterostructure Engineering and Facet Effect Boosts Efficient Reduction CO<sub>2</sub>-to-Ethanol at Low Potential on Cu<sub>2</sub>O@Cu<sub>2</sub>S Catalysts
Jing Li, Rong Cai, Haiqiang Mu, Jia-Xing Guo, Xing Zhong, Jianguo Wang, Xin Du, Jie Zhang, Feng Li
Abstract
Copper oxide (Cu 2 O) is considered a promising catalyst that can effectively reduce the overpotential of the CO 2 reduction reaction (CO 2 RR) and increase the selectivity for C 2+ products. However, developing high-performance and stable of CO 2 -to-ethanol (C 2 H 5 OH) based-Cu 2 O electrocatalysts remains challenging. In this work, Cu 2 O@Cu 2 S twin heterojunction catalysts with multitwin boundaries are designed to afford C 2 H 5 OH productivity at low potential through the electrocatalytic CO 2 RR, and the C 2 H 5 OH selectivity is highly dependent on the facet of Cu 2 O@Cu 2 S with nanocubes outperforming octahedra. Detailed electrochemical experiments, density functional theory (DFT) calculations and in situ infrared spectroscopy reveals that the introduction of Cu 2 S boosts the high coverage of *CO, which can easily spillover to the twin boundaries to generate C 2 H 5 OH through the *CHOH_*CO coupling reaction pathway. A C 2 H 5 OH production begins at an ultralow potential of −0.45 V vs RHE and reaches 34 and 43.9% Faradaic efficiencies (FE) at −0.65 V vs RHE in an H-cell and a flow cell, respectively. Meanwhile, this heterojunction constructed with an interface coherent structure and suitable band structure can facilitate electron transfer from Cu 2 O to Cu 2 S, leading to the stability of Cu + valence states. This work provides an avenue to precisely design C 2 H 5 OH production catalysts by regulating the interface configuration.