Synergistic Ni Single Atoms/Nanoparticles on CeO₂ for High-Performance and Durable SOFC Hydrogen Electrodes

Degradation of the three-phase boundaries in Ni-based anodes at high operating temperature compromises hydrogen oxidation reaction catalytic activity and shortens the lifespan of solid oxide fuel cells. Herein, an oxide-based anode decorated with Ni single atoms (SAs) and nanoparticles (NPs), i.e., e-Ni/CeO₂-5%, is synthesized by combining engineering of UiO-66(Ce) metal organic frameworks (MOFs) and exsolution, where (i) Ni SAs donate electrons to generate oxygen vacancies and stabilize Ni NPs, (ii) NPs dissociate H₂ to facilitate hydrogen spillover, and (iii) the abundant mesoporous channels in CeO₂ inherited from the unique MOFs structure enables high-efficient mass transfer. Synergy of the above merits finally delivers a greatly improved peak power density of 1.46 W cm^-2 at 800°C among oxide-based anodes, exhibits remarkable durability with negligible voltage degradation (< 0.005% h^-1) over 500 h.