Construction of defect-engineered three-dimensionally ordered macroporous WO3 for efficient photocatalytic water oxidation reaction

Abstract

To improve solar light harvesting and charge separation efficiency, we develop a facile strategy for synthesizing defect-engineered three-dimensionally ordered macroporous (3DOM) WO₃ photonic crystals via the colloidal crystal template method and subsequent H₂/N₂ atmosphere thermal treatment. The oxygen evolution rate of the obtained defect-engineered 3DOM WO₃ (W270–400) is 40.1 μmol h⁻¹, which is much higher than that of the untreated 3DOM WO₃ and the defect-engineered WO₃ nanoparticles. The enhanced performance is due to the good light harvesting and excellent charge transportion properties. The results show that the slow photon effect and bulk oxygen vacancy (V_O) induced narrowed band gap greatly improve the light harvesting efficiency, while abundant surface V_O can lower the valence band to increase the driving force for water oxidation, and thus significantly promote electron–hole separation. Our work can guide further design and preparation of high-efficiency defect-engineered 3DOM semiconductors for solar energy conversion.