Electrode Surface Heating with Organic Films Improves CO₂ Reduction Kinetics on Copper

Management of the electrode surface temperature is an understudied aspect of (photo)electrode reactor design for complex reactions, such as CO₂ reduction. In this work, we study the impact of local electrode heating on electrochemical reduction of CO₂ reduction. Using the ferri/ferrocyanide open circuit voltage as a reporter of the effective reaction temperature, we reveal how the interplay of surface heating and convective cooling presents an opportunity for cooptimizing mass transport and thermal assistance of electrochemical reactions, where we focus on reduction of CO₂ to carbon-coupled (C₂₊) products. The introduction of an organic coating on the electrode surface facilitates well-behaved electrode kinetics with near-ambient bulk electrolyte temperature. This approach helps to probe the fundamentals of thermal effects in electrochemical reactions, as demonstrated through Bayesian inference of Tafel kinetic parameters from a suite of high throughput experiments, which reveal a decrease in overpotential for C₂₊ products by 0.1 V on polycrystalline copper via 60 °C surface heating.