title: Phase pure α-Mn2O3prisms and their bifunctional electrocatalytic activity in oxygen evolution and reduction reactions.
abstract: Synthesizing manganese oxide materials with exact control of the nanoparticle shape and phase is difficult, making it challenging to understand the influence of the surface structure on electrocatalysis. Here we describe an inexpensive, low-temperature method to synthesize single-crystal orthorhombic phase α-Mn2O3prisms bound by the {100} facets. The synthesis is the first method to use the cation bridging effect to assist in the creation of α-Mn2O3prisms. According to structural analysis using X-ray diffraction, X-ray pair-distribution function (PDF) measurements and high resolution transmission electron microscopy, the material is composed exclusively of α-Mn2O3prisms, and no additional amorphous or nanocrystalline phases are present. Heating the prisms transformed the material to a more symmetrical, cubic phase α-Mn2O3that exhibited strong bifunctional electrocatalytic activity for the oxygen evolution (OER) and oxygen reduction (ORR) reactions. We compared the oxygen electrode activities (OEA) and found that the α-Mn2O3prisms performed 79% better than commercially-produced α-Mn2O3powders, indicating that these α-Mn2O3prisms perform well as inexpensive, earth-abundant materials for reversible electrodes.
authors.affiliation: International Center for Materials Nanoarchitectonics (WPI-MANA), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan and National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. HENZIE.Joeladam@nims.go.jp.
authors.forename: Maryam
authors.initials: M
authors.lastname: Jahan
authors.affiliation: International Center for Materials Nanoarchitectonics (WPI-MANA), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan and National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. HENZIE.Joeladam@nims.go.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tominaka
authors.affiliation: International Center for Materials Nanoarchitectonics (WPI-MANA), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan and National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. HENZIE.Joeladam@nims.go.jp.
authors.forename: Joel
authors.identifier: http://orcid.org/0000-0002-9190-2645
authors.initials: J
authors.lastname: Henzie