Quasi-1D Mn<sub>2</sub>O<sub>3</sub> Nanostructures Functionalized with First-Row Transition-Metal Oxides as Oxygen Evolution Catalysts
Lorenzo Bigiani, Chiara Maccato, Teresa Andreu, Alberto Gasparotto, C. Sada, Evgeny Modin, Oleg I. Lebedev, J.R. Morante, Davide Barreca
Abstract
The development of cheap and efficient catalysts for the oxygen evolution reaction (OER) plays a critical role for sustainable energy conversion and storage. Herein, we report on Mn2O3-based systems supported on nickel foams and functionalized with first-row transition-metal (Fe, Co, Ni) oxide nanoparticles (NPs) as OER electrocatalysts in alkaline media, fabricated by a plasma-assisted process. The remarkable substrate porosity and high Mn2O3 active area, due to the quasi-one-dimensional nano-organization, enabled an efficient ultradispersion of Fe2O3, Co3O4, and NiO NPs into Mn2O3 and an intimate oxide–oxide interfacial contact, enhancing thus charge carrier transport and facilitating reactants and products diffusion. Among the developed systems, Fe2O3–Mn2O3 yielded the highest electrocatalytic activity, corresponding to a low overpotential of ∼350 mV at 10 mA × cm–2 and a Tafel slope of 70 mV × dec–1, allowing high current density values. The obtained performances, discussed in relation to the material properties, are superior to almost all the state-of-the-art manganese oxide catalysts and compare favorably with various noble-metal-based systems, paving the way to additional activity improvements via compositional and interfacial engineering.