Multi-heterojunction photocatalysts based on WO3 nanorods: Structural design and optimization for enhanced photocatalytic activity under visible light

•(WO3–Pt)/TiO2 multiple heterojunction is fabricated.•The multiple heterojunction has higher activity than single heterojunction.•The activity of multiple heterojunction depends on contact mode of individual component.

The construction of multiple heterojunctions holds promise for enhancing the performance of semiconducting photocatalysts. It can improve charge separation and extend light absorption range via component optimization. Herein, we report the structural design and optimization of a (WO3–Pt)/TiO2 multi-heterojunction photocatalyst based on WO3 nanorods and Pt and TiO2 nanoparticles. The multi-heterojunction-based photocatalyst displayed high activity for the degradation of Rhodamine B dye (RB), phenol, and gaseous acetaldehyde under visible light excitation. Moreover, its activity was higher than single-heterojunction-based photocatalysts, P25 and P25/Pt. The higher performance of the multi-heterojunction-based photocatalyst was attributed to the synergistic effect of efficient conduction band electrons transfer at the WO3/Pt interface and valence band holes transfer at the WO3/TiO2 interface. The photocatalytic performance of the multi-heterojunction-based photocatalyst was also dependent on the location of the loaded Pt nanoparticles. Pt surface loading on WO3, as opposed to loading on the TiO2 surface, was more beneficial in maximizing the photocatalytic activity.

Graphic AbstractThe multiple (WO3–Pt)/TiO2 heterojunction is integrated by WO3 nanorods, TiO2 nanoparticles and Pt nanoparticles. It displays higher activity than single heterojunction photocatalyst, which could be attributed to the synergistic effect of conduction band electrons transfer at WO3/Pt interface and valence band holes transfer at WO3/TiO2 interface.Figure optionsDownload full-size imageDownload as PowerPoint slide