Dynamic surface reconstruction during oxygen evolution enabled by exsolution in Al-doped LaNiO3 for efficient AEM water electrolysis

Abstract

Surface reconstruction during oxygen evolution reaction (OER) has been considered a key mechanism governing the catalytic activity and durability of perovskite oxides. However, effective materials design strategies to regulate surface reconstruction remain limited. In this study, LaNi0.95Al0.05O3 is employed as a model catalyst to demonstrate that the exsolution method functions not only to generate nanoparticles on the surface but also to promote surface reconstruction. The incorporation of irreducible Al dopants preserves the structural stability of LaNiO3 under reducing atmospheres, enabling exsolution without collapse of the perovskite lattice. The developed catalyst exhibits gradual activation during OER operation through the formation of an amorphous layer and achieves an overpotential of 360 mV at 10 mA cm-2 in 1 M KOH at room temperatue. Furthermore, in an anion exchange membrane water electrolysis (AEMWE), this catalyst shows a cell voltage of 1.78 V at 1 A cm-2 at 60oC and maintains stable operation for over 400 h. These findings suggest that the exsolution strategy can be extended beyond nanoparticle decoration to serve as a viable materials design approach for regulating surface reconstruction.