An A-site management and oxygen-deficient regulation strategy with a perovskite oxide electrocatalyst for the oxygen evolution reaction

Abstract

Perovskite oxides (ABO₃) as electrocatalysts applied to the oxygen evolution reaction (OER) have been studied for decades due to their highly flexible and adjustable electronic structures. Herein, a series of LaNiO₃ compounds with different Sn-cation substitutions in the A-site was fabricated and exhibited observable electrocatalytic activity toward the OER. The compositions and structures of the perovskite oxides were systematically investigated via powder X-ray diffraction and high-resolution transmission electron microscopy and found to be hexagonal with the space group Rc(167). The optimized La_0.9Sn_0.1NiO_3−δ catalyst exhibits favorable stability in alkaline electrolyte and enhanced electrocatalytic activity with an overpotential of 318 mV at 10 mA cm⁻² for the OER, which is reduced by 131 mV compared with that of pristine LaNiO₃ (449 mV). Transient photovoltage (TPV) tests confirm the faster interface charge transfer upon Sn substitution. Density function theory (DFT) calculations verify that Sn substitution efficiently enhances the Ni 3d–O 2p covalency and tailors both surface lattice oxygens, boosting the OER performance. This work provides a promising way to design and fabricate a perovskite oxide electrocatalyst for the OER.