BiVO4 hollow microplates: controlled synthesis and enhanced photocatalytic activity achieved through one-step boron doping and Co(OH)2 loading

Abstract

The fabrication of hollow micro- and nanocrystals can not only increase the specific surface area of the materials but also benefit the understanding of the crystal facet-dependent catalytic activity. On the other hand, both the rational doping of heteroatoms and loading of co-catalysts can enhance the photocatalytic activity of semiconductor-based photocatalysts. However, up to now, there have been only a few reports on the synergetic effect of the two. In this work, BiVO₄ hollow microplates (HMPs) and solid microplates (SMPs) were synthesized by a facile hydrothermal route, and B³⁺ ion-doped BiVO₄ HMPs loaded with Co(OH)₂ nanoparticles [Co(OH)₂/B–BiVO₄] were prepared through a one-step impregnation method. The as-prepared products were characterized in detail. The formation mechanism of BiVO₄ HMPs was also proposed on the basis of time-dependent SEM observations and XRD analyses. Taking rhodamine B (RhB) as a kind of pollutant model, the photocatalytic activities of BiVO₄ HMPs, BiVO₄ SMPs, B³⁺ ion-doped BiVO₄ HMPs, BiVO₄ HMPs loaded with Co(OH)₂ nanoparticles, and Co(OH)₂/B–BiVO₄ HMPs were systematically studied. The results show that {010}-dominant BiVO₄ SMPs exhibited better photocatalytic activity for the degradation of RhB than {010} and {110}-dominant BiVO₄ HMPs. In addition, the doping of B³⁺ ions and loading of Co(OH)₂ nanoparticles could synergistically enhance the photocatalytic activity of BiVO₄ HMPs. The present study not only provides reliable evidence for the crystal facet-dependent photocatalytic activity of BiVO₄ but also develops a new strategy for enhancing its photocatalytic activity.