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 λ=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.