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Byles, Bryan W.

Publications and source records attributed to Byles, Bryan W..

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Synthesis strategies toward improved ordering of [MnO 6 ] octahedra in tunnel structured 2 × 3 and 2 × 4 MnO 2

Improved homogeneity of tunnel size in Na-stabilized 2 × 3 and 2 × 4 MnO 2 structures was achieved by identifying and controlling critical synthesis parameters. 2 × 3 and 2 × 4 MnO 2 tunnel manganese oxide nanowires were obtained by hydrothermal treatment of Na-birnessite, a layered manganese oxide that undergoes a layer-to-tunnel transition under high pressure and temperature. Herein, the improved ordering of [MnO 6 ] octahedra is revealed via a combined analysis of X-ray diffraction patterns and scanning transmission electron microscopy images. Furthermore, we show that crystallinity of the Na-birnessite precursor and the chemical composition of the system during hydrothermal treatment are crucial for achieving the targeted size of the structural tunnels with adequate uniformity.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Revealing the Atomic Structures of Exposed Lateral Surfaces for Polymorphic Manganese Dioxide Nanowires

Polymorphic 1D MnO 2 nanostructures are widely applied in fields such as catalysis, sensing, and energy storage with the functionality mainly determined by the atomic patterns of their laterally exposed facets, which largely remain unclear so far. Herein, by high‐resolution transmission electron microscopy (HRTEM) imaging directly along their axial directions, the atomic structures of the outmost lateral facets of polymorphic MnO 2 nanowires are disclosed. To generalize the findings, four most commonly seen phases with characteristic tunnel structures are targeted, i.e., β‐, γ‐, α‐, and todorokite(t)‐MnO 2 , which are synthesized conventionally using a hydrothermal method reported in the literature. Axially imaging these MnO 2 nanowires via HRTEM, the {hkl} facets covering the lateral surfaces are accurately indexed, the atomic pattern of each {hkl} facet is revealed, and it is further coupled with the outmost tunnel configuration that can significantly affect the physicochemical property of MnO 2 materials via tunnel‐driven mass adsorption/transport. This work provides a reliable reference for atomic modeling of MnO 2 to benefit the pursuit of its structure–property relationship; in addition, it can benefit surface engineering strategies to better rationalize the facet growth control with optimized functionality.

Yuan, Yifei↗