Heterogeneous Catalysts as Electrochemical Cells: Completing the Circuit using Proton Buffers in Nonaqueous Media
Year: 2026
Type: preprint
Abstract: Thermochemical redox reactions with heterogeneous catalysts often proceed by an "electrochemical" mechanism that features coupled redox half-reactions. Studies supporting this mechanism have typically been performed with water as the solvent; however, many organic oxidation reactions feature non-aqueous solvent. Here, we analyze the aerobic oxidation of hydroquinone with iron-containing nitrogen-doped carbon (Fe-N-C) catalysts in acetonitrile. Addition of proton buffers significantly accelerates the reaction, and mechanistic data indicate the buffers support proton transfer between the two redox half-reactions, proton-coupled oxidation of the hydroquinone and O2 reduction, which take place at different active sites on the catalyst surface. Kinetic studies of the thermochemical aerobic oxidation reaction are complemented by electrochemical studies, including linear-sweep voltametric analysis of both independent half-reactions. Collectively, the data provide a selfconsistent mechanistic picture that highlights the importance of proton management in supporting thermal heterogeneous catalytic redox reactions in non-aqueous solvent.
Source: ChemRxiv
Institution: University of Wisconsin–Madison
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214726685