Potential of Zero Charge as a Kinetic Descriptor for CO 2 Electroreduction

The rational design of electrocatalysts has long relied on thermodynamic descriptors based on intermediate binding energies. However, such descriptors often overlook potential-dependent surface charging inherent to electrolysis, limiting its ability to capture the reaction kinetics under operational conditions. Here, we identify the potential of zero charge (PZC), which regulates the interfacial electron energy landscape, as a kinetic descriptor for CO2 electroreduction. By evaluating 11 catalysts across a wide pH range (acidic to alkaline), we reveal strong correlations between overpotential and PZC for multiple reaction pathways, including CO, formate, and multicarbon products. Through integrated electrochemical analysis, isotope labeling, in situ spectroscopy, and computational modeling, we show that PZC fundamentally regulates electron-transfer kinetics. At a given negetive potential, a catalyst with a more positive PZC introduces a larger electrostatic contribution to the electron energy to offset their lower chemical potential, which accelerates electron transfer to both the catalyst surface and reaction intermediates. This PZC-based kinetic descriptor further extends to the acidic hydrogen evolution reaction, highlighting its broad applicability across electrocatalytic systems.