Synthesis of 42-faceted bismuth vanadate microcrystals for enhanced photocatalytic activity

Bismuth vanadate (BiVO ₄ ) microcrystals enclosed with up to 42 low and high index facets were synthesized through truncation of BiVO ₄ octahedral crystals via a simple and highly reproducible hydrothermal method. The size and shape of the truncated BiVO ₄ crystals could be tuned by varying the acid concentration, reaction temperature and reaction period. Compared to the BiVO ₄ octahedral crystals without truncation, the 42-faceted ones showed an enhanced photocatalytic activity in the degradation of rhodamine B molecules due to the enhanced charge separation on the exposed low and high index facets. This was confirmed at sub-particle level by the photo-deposition of gold and manganese oxide nanoparticles selectively on hot electron and hole accumulated facets, respectively. Our results will provide a guideline for the synthesis of more efficient BiVO ₄ and many other multinary metal oxide-based photocatalysts. Moreover, the synthesized microcrystals are perfect materials for the study of photocatalytic property of BiVO ₄ at single and sub-particle level.