Strong Electronic Metal–Support Interaction in Ag–Co₃O₄ Heterostructures Enabling Bifunctional Electrocatalysis for Hydrogen Evolution and Glycerol Valorization

Decoupling hydrogen production from oxygen evolution via hybrid glycerol reforming electrocatalysis establishes sustainable pathways for integrated biorefineries and renewable energy storage. However, the practical implementation of this approach is hindered by conventional catalysts’ limitations concerning bifunctional activity, long-term stability, and reliance on precious metals. In this study, we developed a novel heterostructure electrocatalyst by coupling silver nanoparticles with Co3O4 (Ag-Co3O4/NF-1) through a straightforward two-step synthesis strategy. The optimized catalyst demonstrates exceptional HER performance in alkaline media, requiring only 50 mV overpotential to achieve a current density of 10 mA cm–2 while maintaining stability for an extended period of 80 h. For the glycerol oxidation reaction (GOR), it achieves 10 mA cm–2 at a low potential of 1.2 V vs RHE with operational durability lasting up to 100 h. Notably, this system exhibits an unprecedented Faraday efficiency of 96.79% for formic acid at 1.35 V vs RHE. Mechanistic studies and DFT calculations indicate that strengthened catalytic behavior arises from strong electronic metal–support interactions (EMSIs) between Ag and Co3O4, which synergistically optimize the charge transfer kinetics and modulate the active-site electronic configurations. This work establishes design principles for creating high-performance bifunctional electrocatalysts and provides new insights into developing electrocatalysts to valorize biodiesel byproducts.