Structural Phase Transition in BiVO₄ Nanosheets under High Pressure

Abstract

Bismuth vanadate (BiVO 4 ) is a well-known photoanode in photocatalytic engineering. The structural stability and tunability of BiVO 4 are of great interest and importance but have not been well-explored, especially under pressure. Here, we studied the structure evolution of fergusonite-type BiVO 4 nanosheets using in situ synchrotron X-ray diffraction, Raman spectroscopy, ultraviolet−visible absorption spectroscopy, and optical microscopy analysis up to ∼41.7 GPa; despite the previously reported fergusonite to scheelite transition (∼5 GPa in this research) and scheelite to a monoclinic structure transition (∼15 GPa in this research), a potential second-order phase transition at ∼10 GPa in the scheelite phase and an amorphization at ∼16.7 GPa in a high-pressure monoclinic phase have been observed for the first time in this work. These results suggest that BiVO 4 nanosheets exhibit a more complex phase transition routine than their bulk or other nanocounterparts under pressure, which could promote our fundamental understanding and guide the application of orthovanadates.