Manganese\nVanadium Oxide–N-Doped Reduced Graphene\nOxide Composites as Oxygen Reduction and Oxygen Evolution Electrocatalysts

Abstract

The\noxygen evolution reaction (OER) and oxygen reduction reaction\n(ORR) are key catalytic processes for sustainable energy technologies,\nsuch as water electrolysis or fuel cells. Here, a novel metal oxide–nanostructured\ncarbon composite is reported, which acts as OER and ORR electrocatalyst\nunder technologically relevant conditions. A facile synthetic process\nallows the deposition of a molecular manganese vanadium oxide precursor,\n[Mn₄V₄O₁₇(OAc)₃]^3–, on reduced graphene oxide. Simultaneously, the precursor is converted\ninto insoluble nanostructured solid-state Mn–V-oxide catalysts.\nControl of the synthetic conditions allows tuning of the electrocatalytic\nproperties of the composites, leading to excellent and stable electrochemical\nreactivity. The electrocatalytic ORR and OER activity was evaluated\nin alkaline aqueous electrolyte and showed performance comparable\nwith commercial Pt/C electrocatalysts. The study thus demonstrates\nhow polyoxometalate precursors based on earth-abundant elements can\nbe deposited on nanostructured carbon to give high-performance OER/ORR\ncatalysts for alkaline water electrolysis. A new class of composite\ncatalysts can in future be accessed by a facile fabrication route.