Author: Hang Wang (Chongqing University) - The electrochemical reduction of CO₂ (CO2RR) in acidic environments has great potential due to its high carbon utilization and energy efficiency. However, the cross-scale interactions between interfacial transport and reaction kinetics under acidic conditions remain unclear, and the lack of effective strategies for localized microenvironment optimization poses challenges in achieving high selectivity for target products. In this study, a multiscale modeling framework was developed by coupling constant-potential density functional theory (DFT) calculations, microkinetic modeling, and a generalized modified Nernst-Planck equation for interfacial mass transport. This framework successfully reproduces experimental results and accurately quantifies the nonlinear behavior of CO partial current density at high potentials in the presence of competing reactions. The calculation results show that water serves as the primary proton donor in CO₂ reduction, alkali metal cations enhance the interfacial electric field (>40%), thereby facilitating the CO₂ reduction reaction. Additionally, increasing the diffusion layer thickness effectively suppresses the competing hydrogen evolution reaction. Our approach paves the way for microenvironment design in electrochemical CO₂ conversion.
