MOF-derived porous TiO2 decorated with n-type Cu2O for efficient photocatalytic H2 evolution

Abstract

A porous Cu₂O/TiO₂ hybrid photocatalyst with n-type Cu₂O decorated on the mesoporous TiO₂ derived from MIL-125 was designed through the in situ Cu²⁺ ion reduction strategy. Under UV-vis light irradiation, the Cu₂O/TiO₂ composite with 4.2 wt% of Cu₂O displayed the highest hydrogen evolution rate of 14.39 mmol h⁻¹ g⁻¹, which was about 9.6 and 24.8 times that of the original mesoporous TiO₂ and pure Cu₂O, respectively. The enhancement in photocatalytic activity can be mainly attributed to the type-I band structure formed, which can efficiently enhance the photoexcited charge carrier mobility across the phase interfaces of the Cu₂O/TiO₂ composite, as evidenced by the UV-DRS spectra, Mott–Schottky curves, and XPS analysis. Besides, the narrow band gap of Cu₂O, conducive to the absorption of visible light, and the high specific surface of TiO₂ were also found to contribute to the photoactivity enhancement. This work will provide a new perspective for the study of type-I photocatalysts.