State Key Laboratory of Space Power-Sources Technology, Shanghai Institute of Space Power Sources, Shanghai 200245, China
Xiaodong Zhuang
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China
Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Fudan University, Shanghai 200438, China
Kun Jiang
Interdisciplinary Research Center, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 201306, China; Corresponding author.
Electrochemical CO2 reduction is a typical surface-mediated reaction, with its reaction kinetics and product distributions largely dependent on the dynamic evolution of reactive species at the cathode–catholyte interface and on the resultant mass transport within the hydrodynamic boundary layer in the vicinity of the cathode. To resolve the complex local reaction environment of branching CO2 reduction pathways, we here present a differential electrochemical mass spectroscopic (DEMS) approach for Cu electrodes to investigate CO2 mass transport, the local concentration gradients of buffering anions, and the Cu surface topology effects on CO2 electrolysis selectivity at a temporal resolution of ∼400 ms. As a proof of concept, these tuning knobs were validated on an anion exchange membrane electrolyzer, which delivered a Faradaic efficiency of up to 40.4% and a partial current density of 121 mA cm−2 for CO2-to-C2H4 valorization. This methodology, which bridges the study of fundamental surface electrochemistry and the upgrading of practical electrolyzer performance, could be of general interest in helping to achieve a sustainable circular carbon economy.
