Pristine Bi2WO6 and hybrid Au-Bi2WO6 hollow microspheres with excellent photocatalytic activities

Pristine Bi₂WO₆ hollow microspheres have been fabricated in ethylene glycol-water system with CTAB as crystal growth director for the first time, hybrid Au- Bi₂WO₆ hollow microspheres was also obtained by in situ decoration of Au nanoparticles, the formation mechanisms were explored. Their photocatalytic activities on photo-reduction of Cr(VI) and photo-degradation of phenol in aqueous solution were investigated under visible light irradiation. Hybrid Au- Bi₂WO₆ hollow microspheres displayed the highest photocatalytic activity, exhibiting a nearly complete reduction of Cr(VI) to Cr(III) within only 20 min. The excellent photocatalytic activities of heterogeneous Au-Bi₂WO₆ hollow microspheres can be induced by the increased light harvesting efficiency (due to light multi-scattering effect of hollow architecture), high separation of photogenerated electron-hole pairs caused by electron trapping effect and surface plasmon resonance (SPR) effect of Au nanoparticles.