Electronic structure modulation in Ag nanoparticle-Ag2Cu2O3 catalyst: a strategy for stable and enhanced oxygen reduction reaction.

The Oxygen Reduction Reaction (ORR) is a critical electrochemical process essential for the operation of sustainable energy devices, such as fuel cells and metal-air batteries. However, its sluggish kinetics demand an efficient electrocatalyst to achieve durable performance. This work reports the excellent and robust ORR activity of silver nanoparticle-anchored Ag2Cu2O3, attributed to the synergistic interaction and strong interfacial coupling between the AgNPs and the Ag-Cu mixed metal oxide. DFT computations reveal that this interaction effectively modulates the electronic structure of silver, shifting its d-band centre towards the Fermi level. This modification optimises the kinetics of oxygen adsorption and desorption, overcoming the kinetic limitations of ORR. An anion exchange membrane electrode assembly (MEA) utilising the Ag@Ag2Cu2O3 cathode catalyst demonstrated promising performance in a single active direct methanol fuel cell (DMFC), achieving a current density of 48 mA cm-2 and a peak power density of 5 mW cm-2 operating at 40 °C. These results contribute to a deeper understanding of structure-activity relationships and offer a new strategy for designing high-performance catalysts for next-generation fuel cells.