WS 2 and C-TiO 2 Nanorods Acting as Effective Charge Separators on g-C 3 N 4 to Boost Visible-Light Activated Hydrogen Production from Seawater

ChemSusChem. 2018 Dec 11;11(23):4077-4085. doi: 10.1002/cssc.201801819. Epub 2018 Oct 24.

Abstract

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-C3 N4 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-C3 N4 , WS2 , C-TiO2 nanorods, and the reference-modified g-C3 N4 composite with individual WS2 or C-TiO2 nanorods. Co-modified g-C3 N4 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-C3 N4 composite in seawater solution is 13.08 %, which is higher than pure g-C3 N4 (5.06 %). WS2 , TiO2 , and g-C3 N4 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-C3 N4 composite with high photocatalytic performance provides a promising candidate for rationally utilizing the seawater resource to produce clean chemical energy.

Keywords: charge separators; g-C3N4 composite; hydrogen; photocatalysis; seawater splitting.