WS2 and C-TiO2 Nanorods Acting as Effective Charge Separators on g-C3N4 to Boost Visible-Light Activated Hydrogen Production from Seawater

Semiconductor photocatalysis is regarded as an ideal method for use in solving the energy shortage and environmental issues by converting solar energy to chemical energy. Herein, we have designed a facile synthetic methodology to obtain a ternary co-modified g-C3N4 composite via WS2 and carbon-doped TiO2 (C-TiO2) nanorods with highly efficient photocatalytic activity for hydrogen production from deionized (DI) water and a natural seawater system under visible-light illumination. This composite exhibits enhanced photocatalytic activity compared to the pristine g-C3N4, WS2, C-TiO2 nanorods, and the reference-modified g-C3N4 composite with individual WS2 or C-TiO2 nanorods. Co-modified g-C3N4 composite shows a great photostability in both DI water and seawater. Under lambda = 420 nm monochromatic light illumination, the apparent quantum efficiency of the co-modified g-C3N4 composite in seawater solution is 13.08%, which is higher than pure g-C3N4 (5.06%). WS2, TiO2, and g-C3N4 constitute a ternary heterojunction boosting the fast separation of photoinduced electron-hole pairs, which plays a crucial role in enhancing photocatalytic activity. Therefore, the WS2 and C-TiO2 nanorod co-modified g-C3N4 composite with high photocatalytic performance provides a promising candidate for rationally utilizing the seawater resource to produce clean chemical energy.