Surface chlorine doped perovskite-type cobaltate lanthanum for water oxidation

Rationally manipulating the in-situ formed catalytically active surface of catalysts remains a great challenge for a highly efficient water electrolysis. Here, we report a cationic oxidation method which can adjust the leaching of the in-situ catalyst and promote the reconstruction of dynamic surface for the oxygen evolution reaction (OER). The chlorine doping can reduce the possibility of triggering in-situ cobalt oxidation and chlorine leaching, leading to a transformation of the surface chlorine doped LaCoO3 (Cl-LaCoO3) into an intricate amorphous (oxygen) hydroxide phase. And thus, Cl-LaCoO3 nanocrystals shows an ultralow overpotential of 342 mV at the current density of 10 mA cm−2 and Tafel slope of 76.2 mV dec−1. Surface reconstructed Cl-LaCoO3 is better than many of the most advanced OER catalysts and has proven significant stability. This work provides a new prospect for designing a high-efficiency electrocatalyst with optimized perovskite-structure in renewable energy system.