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 TiO2, 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 MnOx, are spatially separated anchored on the inner and outer surfaces of TiO2@WO3 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 WO3 (<450 nm), and scattering in hollow nanospheres synergistically improve the absorption of sunlight. As a result, the as-prepared TiO2@WO3 hollow sphere decorated with Au and MnOx exhibits an exceptional photocatalytic activity of phenol degradation compared with pure TiO2@WO3 hollow nanosphere or TiO2@WO3 hollow nanosphere decorated with single cocatalyst Au or MnOx. This work fully demonstrates that the designed type-II heterogeneous structures with the spatially separated dual cocatalysts is a promising solution for enhancing photocatalysis performance.