Microenvironment Engineering of CO2 Electrolysis to Multicarbon Products in Acidic Electrolyte

Description

Electrochemical CO2reduction (CO2R) to multicarbon (C2+) products using renewable energies is a promising strategy to realize CO2utilization and carbon neutrality. In particular, CO2R in acidic electrolyte holds great promise as it can avoid the problem of CO2loss that occurs in alkaline and neutral electrolytes. However, the acidic environment with excessive protons near catalyst surface suppresses C-C coupling, leading to poor selectivity and low energy efficiency for C2+products. The project aims to optimize CO2electrolysis in strongly acidic media by regulating the catalyst microenvironment through surface functionalization and dilution of CO2concentration. The objective includes three main aspects: (1) establishing correlations of CO2R product distribution vs surface functionalization and CO2concentration at moderate current densities (100-400 mA cm-2); (2) revealing the mechanism of CO2R on such microenvironment-controlled catalyst/electrode through advanced in-situ techniques and Density Functional Theory (DFT) calculations. Operando proton-transfer-reaction time-of-flight mass spectrometry and Raman spectroscopy allow for identification and monitoring of intermediates and their evolution with CO2concentration, while DFT calculations provide insights into the reaction barriers of C-C coupling with varying adsorbate coverage; and (3) enhancing the energy efficiency and carbon efficiency toward C2+products under optimized conditions, including feed concentrations, flow rates, electrolyte compositions, current densities, surface functionalization level and gas diffusion electrode configuration. Successful implementation of this proposal would offer valuable guidance for tuning CO2mass transport and regulating microenvironment in gas-diffusion electrode based electrolyzers, facilitating the production of valuable multicarbon products and promoting the practical application of CO2electrolysis technology.