Synergistic Ag-Ni-P interfacial modulation achieves high-performance Co3O4 oxygen evolution reaction catalysts for anion exchange membrane water electrolyzers

초록

Efficient and durable oxygen evolution reaction (OER) catalysts are essential for anion exchange membrane water electrolysis (AEMWE). In this study, a multi-element-modified Co3O4 catalyst (Ag/P-NCO-10) is developed by incorporating Ni and P into a spinel lattice, together with metallic Ag nanoparticles. Structural analyses confirm the formation of substitutional solid solutions upon Ni-and P-doping, whereas Ag remains as a conductive metallic phase. Density functional theory calculations reveal that Ni doping increased the electronic density near the Fermi level, enhancing charge-transfer capability and lowering the energy barrier of the rate-determining O* -> OOH* step. The Ag nanoparticles further decrease the interfacial charge-transfer resistance without participating in catalytic adsorption. Ag/P-NCO-10 delivers the lowest calculated reaction barrier and highest experimental OER activity, achieving an overpotential of 296 mV at 10 mA cm-2 and excellent stability. As a self-supported electrode in AEMWE single-cell testing, it achieves a current density of 1.27 A cm-2 at 1.8 V and maintains a degradation rate of-1.5 mu A cm-2 h-1 over 100 h with a cell efficiency of 78.8%. Overall, these results demonstrate the synergistic multi-element modulation of Co3O4 effectively tailored the surface energetics and electron-transport pathways, offering a promising strategy to designing high-performance, durable anodes for AEMWE.

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