Mechanism of formation, structural characteristics and photocatalytic activities of hierarchical-structured bismuth-tungstate particles
| Autor: | Fumiaki Amano, Tamaki Shibayama, Mai Takase, Mai Takashima, Haruna Hori, Bunsho Ohtani |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Scanning electron microscope chemistry.chemical_element Nanotechnology 02 engineering and technology Crystal structure Tungsten 010402 general chemistry Reaction at the boundarya 01 natural sciences Catalysis Hydrothermal circulation Hollow particle Bismuth Bismuth oxyhydroxide chemistry.chemical_compound Tungstate General Chemistry 021001 nanoscience & nanotechnology 0104 chemical sciences Core-shell-structured droplet chemistry Chemical engineering Transmission electron microscopy Tungstic acid Hierarchical flake-ball structure 0210 nano-technology |
| Zdroj: | Catalysis today. 300:99-111 |
| ISSN: | 0920-5861 |
| Popis: | The mechanism of the formation of flake ball-shaped (FB) bismuth-tungstate (BWO) particles was studied with samples prepared by hydrothermal reactions under standard conditions (tungsten/bismuth ratio of 0.55 in feed; 433 K; 20 h) and other modified conditions, and the structural characteristics of the samples were analyzed by powder X-ray diffraction (composition and crystal structure), field emission-type scanning electron microscopy (FE-SEM) (morphology), focused ion-beam etching followed by FE-SEM (inner void structure), ultrahigh-voltage transmission electron microscopy (inner void structure) and low-voltage scanning electron microscopy with energy-dispersive X-ray spectroscopic analysis (morphology and elemental distribution). Based on the results, a novel two-step mechanism of (1) formation of aqueous bismuth-oxyhydroxide droplets covered by tungstic acid (BOx@HWO) with fluidity and (2) reaction of inner bismuth and outer tungsten components at the BOx@HWO surface to yield BWO flakes is proposed as a one of the most plausible pathways that are consistent with the hollow structure of FB BWO and observations of the products prepared with shorter hydrothermal reaction. Photocatalytic activities of FB BWO samples in relation to their structure were studied. |
| Databáze: | OpenAIRE |
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