Intercalated water drives anomalous thermal expansion in the tetragonal zircon structured bismuth vanadate BiVO4 photocatalyst
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Date
2024-07-15
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
The thermal transformation of the tetragonal‐zircon (tz‐) to tetragonal‐scheelite (ts‐)BiVO4was studied byin situsynchrotron X‐ray diffraction, thermogravimetric analysis, and Fourier‐transformed infrared spectroscopy. Upon heating, the tetragonal zircon polymorph of BiVO4(tz‐BiVO4) transitioned to thets‐polymorph between 693–773 K. Above 773 K, single phasets‐BiVO4was observed before transitioning to the monoclinic fergusonite (mf‐) polymorph upon cooling. An anomaly in thermal expansion was observed between 400–500 K, associated with the loss of intercalated H2O/NH4+from the coprecipitation procedure. Heatingtz‐BiVO4resulted in contraction of the V−O bond distance and VO4polyhedra volume, ascribed to rotation of the tetrahedra groups. Attempts to study this by neutron diffraction failed due to the large incoherent scatter from the hydrogenous species. Efforts to remove these species while maintaining thetz‐BiVO4structure were unsuccessful, suggesting they play a role in stabilizing thetz‐polymorph. The local structure of bothmf‐BiVO4 andtz‐BiVO4 were investigated by X‐ray pair distribution function analysis, revealing local distortions. © 2024 The Authors. Chemistry - An Asian Journal published by Wiley-VCH GmbH.
Description
Keywords
Water, Zircon, Bismuth, Photocatalysis, Synchrotrons, Neutron diffraction, Thermal expansion, Heating, Dielectric properties
Citation
Mullens, B. G., Marlton, F. P., Nicholas, M. K., Permana, A. J., Brand, H. E. A., Maynard-Casely, H. E., Chater, P. A., & Kennedy, B. J. (2024). Intercalated water drives anomalous thermal expansion in the tetragonal zircon structured bismuth vanadate BiVO4 photocatalyst. Chemistry – An Asian Journal, 19(14), e202400408. doi:10.1002/asia.202400408