<p>Hydrogen peroxide is manufactured industrially via the anthraquinone autoxidation process—a typical thermocatalytic non-aqueous method. Despite a high interest in using renewable electricity to drive such processes, electrifying non-aqueous syntheses remains a substantial challenge. Here we present a multi-phase electrochemical anthraquinone autoxidation process that leverages an aqueous–non-aqueous interfacial proton-coupled electron transfer method facilitated by heterogeneous molecular mediation. This design enables the reduction of aqueous anthraquinones with high efficiency at high current densities, using only carbon electrodes. The method operates with high selectivity through a quinhydrone intermediate and prevents the over-reduction of aromatics during thermocatalytic hydrogenation. This approach combines the benefits of aqueous electrochemistry with those of the traditional non-aqueous process to achieve high current density electrochemistry with rapid kinetics and mass transport, while avoiding unwanted electrolyte in the hydrogen peroxide product. This strategy bridges aqueous electrochemistry with non-aqueous chemistry and establishes a framework for the electrification and decentralization of other non-aqueous chemical processes.</p><p></p>