Synergistic Mechanism for Unconventional Anodic Reaction of Aldehyde Oxidation for Hydrogen Production

Anodic reactions involving non-faradaic processes have significantly expanded the potential application of anodic oxidation half-reactions. Metallic Cu materials can catalyze an unconventional anodic aldehyde oxidation reaction involving the non-faradaic H₂ production (AOR-H₂). AOR-H₂ has distinct advantages of ultra-low thermodynamic potentials and high value-added redox products, etc., but the question of exactly how reduction steps occur during AOR-H₂, is something which has long puzzled scientists. Here we illustrate the novel synergistic mechanism of nonelectrochemical/electrochemical redox steps in AOR-H₂. Aldehyde undergoes hydration, deprotonation, and spontaneous C–H homolytic cleavage to generate H₂, and then is electrochemically oxidized to form carboxylate. Decorating Cu catalysts with metallic Pt species, supported by theoretical calculations, leads to a 12-fold increase in the intrinsic activity of AOR-H₂. This work inspires researchers to develop novel cathodic and anodic reactions involving the non-faradaic process for breaking through the limit of existing energy conversion systems.