Acid-Stable Cu Cluster Precatalysts Enable High Energy and Carbon Efficiency in CO<sub>2</sub> Electroreduction
Dongha Kim, Sungjin Park, Junwoo Lee, Yiqing Chen, Li Feng, Jiheon Kim, Yang Bai, Jianan Erick Huang, Shijie Liu, Eui Dae Jung, Byoung‐Hoon Lee, Panagiotis Papangelakis, Weiyan Ni, Tartela Alkayyali, Rui Kai Miao, Peihao Li, Yongxiang Liang, Ali Shayesteh Zeraati, Roham Dorakhan, Debora Meira, Yanna Chen, David Sinton, Mingjiang Zhong, Edward H. Sargent
Abstract
The electrochemical reduction of CO 2 in acidic media offers the advantage of high carbon utilization, but achieving high selectivity to C 2+ products at a low overpotential remains a challenge. We identified the chemical instability of oxide-derived Cu catalysts as a reason that advances in neutral/alkaline electrolysis do not translate to acidic conditions. In acid, Cu ions leach from Cu oxides, leading to the deactivation of the C 2+ -active sites of Cu nanoparticles. This prompted us to design acid-stable Cu cluster precatalysts that are reduced in situ to active Cu nanoparticles in strong acid. Operando Raman and X-ray spectroscopy indicated that the bonding between the Cu cluster precatalyst ligand and in situ formed Cu nanoparticles preserves a high density of undercoordinated Cu sites, resulting in a C 2 H 4 Faradaic efficiency of 62% at a low overpotential. The result is a 1.4-fold increase in energy efficiency compared with previous acidic CO 2 -to-C 2+ electrocatalytic systems.