Mesoporous hierarchical bismuth tungstate as a highly efficient visible-light-driven photocatalyst

The synthesis of flower-like hierarchical bismuth tungstate (Bi ₂WO₆) consisting of a mesoporous surface was carried out by a hydrothermal method using the non-ionic surfactant Pluronic F127. The mesoporous and hierarchical surface of the bismuth tungstate was further modified with platinum nanoparticles and the photocatalytic activity was evaluated by studying the removal of rhodamine B under visible light (>420 nm). The effect of synthesis temperature and platinum amount on the photocatalytic activity was investigated and resulting photocatalytic activity of Pt/Bi₂WO₆ was compared with other visible-light- responsive photocatalysts, namely Pt/WO₃, N-doped TiO₂ and Pt/N-doped TiO₂. Photoelectrochemical studies were performed to shed light on the involvement of excited charged carriers in the photooxidation of rhodamine B and a plausible mechanism was proposed based on the photocatalytic and photoelectrochemical behaviour of the catalysts.