Facet-evolution growth of Mn₃O₄@Co_xMn_3-xO₄ electrocatalysts on Ni foam towards efficient oxygen evolution reaction

Developing efficient and stable non-noble electrocatalysts for oxygen evolution reaction (OER) is one of the promising and challenging issues. This paper describes an approach to prepare core-shell cobalt-manganese oxides with specific morphologies and oxygen vacancies. Via a facile seed growth method, facets evolution is achieved during the formation of core-shell structure. Benefited from optimized surface environment, oxygen vacancy-enriched octahedral cobalt-manganese oxides supported on Ni foam exhibited relatively low overpotential of 284 mV at the current density of 10 mA cm⁻² and diminutive tafel slope of 73.1 mV dec⁻¹ as well as long-term stability. This work successfully unveils a method for facet-modulation of core-shell metal oxides as efficient electrochemical OER catalysts.