Simple construction of amorphous monometallic cobalt‐based selenite nanoparticles using ball milling for highly efficient oxygen evolution reaction

Amorphous transition-metal based materials with disordered structure are very desirable in the field of sustainable energy devices and technologies such as water-splitting and secondary batteries due to their inherent properties of anisotropy and defects. To date, it is very urgent to explore new methods to prepare amorphous electrocatalysts. Herein, we use a simple approach to construct amorphous Co-based selenite electrocatalyst by mechanical ball milling for oxygen evolution reaction (OER). Due to its amorphous structure as well as more active species, the obtained amorphous cobalt selenite C4S-12 h material on the glassy carbon electrode shows superior electrochemical performance with a low overpotential of 255 mV to drive 10 mA cm(-2) in 1.0 M KOH electrolyte. In addition, this catalyst also has an excellent intrinsic activity (high mass activity of 162.0 A g(-1) and TOF of 0.063 s(-1) at the overpotential of 350 mV) and remarkable long-term stability (at least 32 h at a current density of 10 mA cm(-2)). This study offers a simple and environmentally friendly method to construct highly efficient electrocatalysts for water oxidation.