PNNL

Abstract

LaNiO3 is a well studied and promising oxygen electrocatalyst for renewable energy storage and conversion technologies. Here we show that strontium substitution for lanthanum in coherently-strained, epitaxial LaNiO3 films (La1-xSrxNiO3 with 0 = x = 1) significantly enhances the oxygen evolution reaction (OER) activity, resulting in performance at x = 0.5 comparable to the state-of-the-art catalyst Ba0.5Sr0.5Co0.8Fe0.2O3-?. By combining X-ray photoemission and X-ray absorption spectroscopies with density functional theory, we show that an upward energy shift of the O 2p band relative to the Fermi level occurs with increasing x in La1-xSrxNiO3. This alloying step strengthens Ni 3d-O 2p hybridization and decreases the charge transfer energy, which in turn accounts for the enhanced OER activity.