The incorporation of Ce into Co-Mn oxides induced the charge redistribution of Co and Mn via electronic coupling, which facilitated the Co³⁺/Co⁴⁺ transition. Thus, the overpotential at 10 mA cm⁻² was reduced significantly by 73 mV for the oxygen evolution reaction after Ce doping.

https://doi.org/10.1039/d2cc04415c