Mimicking Formate Oxidase with Pd–Pt Nanozymes on Carbon Dot-Functionalized Graphene Oxide Support for Formic Acid/O ₂ Biofuel Cells

Formic acid (FA), a common biomass-derived product, is often utilized as an anode fuel in sustainable energy devices. The anti-CO poisoning capability is a critical evaluation criterion for the FA oxidation reaction. Inspired by the natural enzymatic oxidation of FA in biological systems, we designed Pd–Pt alloy nanozymes to mimic the aerobic oxidation of FA by natural formate oxidase (FOD). Carbon dots were used to immobilize and disperse nanoparticles on the surfaces of graphene oxide aerogels for electrocatalytic FA oxidation. Simultaneously, the 3D structure of the aerogel significantly enhances the catalytic activity by boosting efficient mass transport of the reactant and rapid electron transfer from the catalytic sites. Moreover, we constructed an FA/O2 enzymatic biofuel cell (EBFC) with the enzyme biocathode. Through rational engineering design, the device delivered a remarkable power output of 1.20 mW cm–2 even at low FA concentrations. This work not only offers novel strategies for developing advanced FOD mimics but also demonstrates the feasibility of practical applications by further enhancing the EBFC performance through engineering optimizations.