Synergistic interaction between in situ exsolved and phosphorized nanoparticles and perovskite oxides for enhanced electrochemical water splitting

Abstract

Highly active and stable catalysts towards electrochemical water-splitting are critical for the sustainable energy conversion and storage. Perovskite oxides with in situ exsolved metal nanoparticles have emerged as promising candidates, while their activities are still unsatisfying and mechanisms unclear. Here we develop a novel hybrid catalyst with the in situ exsolved and phosphorized Co nanoparticles on Sr2FeMoO6 perovskite oxide surface based on density functional theory predictions, and use it as a model system to investigate the particle-substrate interactions with combined experimental studies and theoretical calculations. The as-prepared electrocatalyst exhibits boosted activity and stability for oxygen evolution reaction, hydrogen evolution reaction and overall water-splitting in alkaline solution, comparable to these of precious-metal catalysts. Further studies reveal the phase transformation during catalysis and the strong interactions between the phosphorized Co nanoparticles and perovskite oxide substrate. The modulated band structure, redistributed charge density and spillover effect lead to the enhanced charge transfer, increased O covalency, optimized intermediate adsorption and reduced energy barrier, enhancing the overall activity synergistically.