Hydrothermal synthesis of α-MnO2/MIL-101(Cr) composite and its bifunctional electrocatalytic activity for oxygen reduction/evolution reactions

•An α-MnO2/MIL-101(Cr) composite was synthesised using a hydrothermal process.•The composite exhibits excellent ORR and OER in an alkaline electrolyte.•The improvement in activity is related to micropores surrounding the α-MnO2.•The stability is related to the interaction between the α-MnO2 and the MIL-101(Cr).

An α-MnO2/MIL-101(Cr) composite catalyst was synthesised using a hydrothermal process. In this composite, α-MnO2 nanoparticles are embedded in an MIL-101(Cr) matrix with abundant micropores and a high specific surface area, which improves the reactant's accessibility to catalytically active sites, resulting in a significant improvement in oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in an alkaline electrolyte. The strong interactions between α-MnO2 nanoparticles and MIL-101(Cr) matrix result in a high structural stability and therefore excellent activity stability.