High-valence Co deposition based on selfcatalysis of lattice Mn doping for robust acid water oxidation

Abstract

Non-precious metal cobalt-based oxide inevitably dissolves for acid oxygen evolution reaction (OER). Designing an efficient deposition channel for leaching cobalt species is a promising approach. The dissolution-deposition equilibrium of Co is achieved by doping Mn in the lattice of LaCo_1−xMn_xO₃, prolonging the lifespan in acidic conditions by 14 times. The lattice doping of Mn produces a strain that enhances the adsorption capacity of OH⁻. The self-catalysis of Mn causes the leaching Co to be deposited in the form of CoO₂, which ensures that the long-term stability of LaCo_1−xMn_xO₃ is 70 h instead of 5 h for LaCoO₃. Mn doping enhances the deprotonation of *OOH → O₂ in acidic environments. Notably, the overpotential of optimized LaCo_1−xMn_xO₃ is 345 mV at 10 mA cm⁻² for acidic OER. This work presents a promising method for developing noble metal-free catalysts that enhance the acidic OER activity and stability.