Spatially separated dual cocatalysts on type-II heterojunction TiO2@WO3 hollow nanospheres for photocatalytic degradation of phenol

The construction of photocatalysts with high sunlight absorption capacity and fast photogenerated carrier separation is essential for environmental remediation and solar energy conversion. However, metal oxides, such as TiO 2 , still suffer from the severe recombination of photogenerated charge carriers and the low consumption of sunlight. The type-II heterojunction hollow structure decorated with dual co-catalysts were proposed to simultaneously address the issues in charge separation and sunlight absorption. Herein, bifunctional cocatalysts, Au and MnO x , are spatially separated anchored on the inner and outer surfaces of TiO 2 @WO 3 heterogeneous hollow nanospheres. The spatially separated dual cocatalysts promoted the separation of photogenerated charge carriers by steering the photogenerated electrons and holes in opposite directions. Additionally, the surface plasmon resonance absorption of co-catalysts Au nanoparticles (450-600   nm) and light absorption of WO 3 (<450   nm), and scattering in hollow nanospheres synergistically improve the absorption of sunlight. As a result, the as-prepared TiO 2 @WO 3 hollow sphere decorated with Au and MnO x exhibits an exceptional photocatalytic degradation of phenol compared with pure TiO 2 @WO 3 hollow sphere or TiO 2 @WO 3 hollow sphere decorated with single cocatalyst Au or MnO x . This work fully demonstrates that the designed type-II heterogeneous structures with the spatially separated cocatalysts are a promising solution for enhancing photocatalysis performance.