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

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.