Mechanistic insights into the electrochemical oxidation of acetate at noble metals

Abstract

Electrochemical acetate oxidation (AcOR) offers a sustainable approach to produce renewable biofuels. While CO₂ formation is thermodynamically favored, acetate oxidation can also yield various products through the Kolbe and Hofer-Moest mechanisms, enabling a modulation of the products formed via partial oxidation. Given the complexity of the reaction, it is crucial to understand how different reaction conditions influence the product profile. Furthermore, this process generates methyl radicals, providing insights into methane partial oxidation. The current study explores AcOR on noble metal electrodes (Pt, Pd, Au) in a 0.5 M CH₃COOK aqueous electrolyte, revealing the mechanism of product formation using potential- and time-dependent electrolysis and isotope-labeling experiments. The effect of surface chemistry, ion transport, electrolyte concentration, and electrolysis techniques on product selectivity is analyzed. Additionally, the study compares product profiles from an electrolyzer cell to those obtained from model electrodes in batch-cell setup.