Abstract
Earth-abundant metal oxides are excellent candidates for photocatalytic applications due to their low cost and high stability in aqueous solutions. Materials that contain a combination of metal cations with an s2 electron lone pair and a d0 electronic configuration, such as BiVO4, possess favorable band gaps. BiVO4 has also been reported to possess noncentrosymmetric polar properties, such as flexoelectricity, piezo-photocatalysis, and an anomalous photovoltaic effect, despite its centrosymmetric crystal structure. Here, it is shown how centrosymmetric materials possessing s2 and d0 cations can display “hidden” local-scale features, often ignored by conventional crystallography, that influence their physical properties. Anomalous peak shapes are observed in the high-resolution synchrotron X-ray powder diffraction of BiVO4, and temperature-dependent local-scale distortions are revealed using neutron total scattering methods. Together, these suggest the polar properties of BiVO4 are related to local-scale distortions induced by the Bi3+ 6s2 electron lone pairs. This demonstrates the possibility of engineering specific interatomic distances between lone pair-bearing cations and the anion sublattice, creating new opportunities for photocatalytic and polar materials from compounds with long-range centrosymmetric structures.
| Original language | English |
|---|---|
| Pages (from-to) | 7840-7848 |
| Number of pages | 9 |
| Journal | Journal of the American Chemical Society |
| Volume | 147 |
| Issue number | 9 |
| DOIs | |
| State | Published - Mar 5 2025 |
Funding
We acknowledge the support of the Australian Research Council for this work, which was facilitated by access to Sydney Analytical, a core research facility at the University of Sydney. High-energy synchrotron diffraction experiments were supported as part of GENESIS: A Next Generation Synthesis Center, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Basic Energy Sciences under award number DESC0019212. B.G.M. thanks the Australian Institute for Nuclear Science and Engineering for a PGRA and SAAFE scholarship. B.G.M. completed part of this research while undertaking a Fulbright Future Scholarship funded by the Kinghorn Foundation. Beamtime at the Powder Diffraction beamline (M18437) at the Australian Synchrotron is greatly acknowledged. Beamtime on Wombat and Echidna (P13946) at the Australian Centre for Neutron Scattering is greatly acknowledged. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory with beamtime on NOMAD (IPTS #30348) and POWGEN (IPTS #33606) greatly acknowledged. This research used resources at beamline 11-ID-B of the Advanced Photon Source, a US Department of Energy Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357.