Oxygen vacancy stimulated direct Z-scheme of mesoporous Cu2O/TiO2 for enhanced photocatalytic hydrogen production from water and seawater

Oxygen vacancy stimulated direct Z-scheme Cu2O/TiO2 hybrid photocatalysts were designed and constructed through a Cu2+ ions adsorption-reduction strategy with Cu2O nanospecies decorated on/within mesoporous TiO2 microspheres. Narrow band gap of Cu2O favors visible light absorption. The mesoporous structure stabilizes Cu2O nanospecies and benefits the efficient charge carrier mobility and light harvest. The high specific surface area provides more photocatalytic active sites for both Cu2O and TiO2 components. Oxygen vacancy stimulated all-solid direct Z-scheme electron transport mechanism was proposed to explain the high activity and stability of the hybrid catalyst. The catalyst behaves enhanced hydrogen evolution rate of 11 mmol h−1 g−1 in water and 5.1 mmol h−1 g−1 in seawater, respectively. The highest AQY of hydrogen production is 15.1% in water (and 8.4% in seawater) at 365 nm. The work will provide new insight for controllable creation of Z-scheme photocatalysts for practical hydrogen evolution from water and seawater splitting.