Manganese doped hollow cobalt oxide catalysts for highly efficient oxygen evolution in wide pH range

Heteroatomic substitution of spinel oxides can theoretically optimize oxygen evolution reaction (OER) via redistribution of charges and modification of d -band center. However, the wide pH range of electrocatalysis and catalytic mechanism are still great challenges. Herein, we successfully construct heteroatom Mn-substituted spinel Co3O4 (Mn-Co3O4) with porous hollow sphere structure for highly efficient and wide pH range OER. Benefiting from the atomic Mn-substitution and charge transfer, the Co site in Mn-Co3O4 displays an increased ratio of Co3+/Co2+. Electrochemical measurements demonstrate that Mn-Co3O4 exhibited superior OER activities with small overpotentials of only 305, 520 and 460 mV to afford a current density of 10 mA cm -2 in alkaline, neutral and acidic media, respectively. Meanwhile, Mn-Co3O4 also possesses favorable long-term stability in wide -pH electrolyte. The improved reaction kinetics of Mn-Co3O4 are mainly attributed to the unique hollow sphere structure with high specific surface area, and the increased high valency of Co, which can introduce the dband center modification of Mn-Co3O4, and reduce the adsorption energy of oxygen intermediates in ratedetermining step (RDS).