Z-scheme induced g-C3N4 /WS2 heterojunction photocatalyst with improved electron mobility for enhanced solar photocatalysis

This study reports the hybridization of g-C3N4/WS2 prepared through one-pot hydrothermal synthesis in the absence of a reducing agent. Heterojunction samples of varied WS2 compositions and fixed g-C3N4 concentrations (CNW-0.5, CNW-1.0 and CNW-1.5) were synthesized. All samples were physiochemically and electrochemically examined to understand their materials’ chemistry and performance. The particle size of the composite varied from 2.55 µm to 2.58 µm with a high crystalline structure. The Nyquist Plot demonstrated an improved charge mobility, and the transient photo current showed a prolonged lifetime of the charge carriers for the CNW-1.0 sample. The Mott Schottky plot proved the p-n junction formation of the composite with a potential energy barrier at the junction. The time-resolved transient PL decay curves demonstrated an average lifetime (τavg) of 8.51 μs for CNW-1.0, which was 2.6 times higher than that of WS2 alone. The highest solar photocatalytic degradation of 95.5% for Methylene Blue and 84.5% for Tetracycline were achieved with CNW-1.0 in 2 h, where (̇O2–) and (OḢ) radicals were dominant in the reaction. The obtained band positions suggested the Z-Scheme mechanism for the charge mobility across the heterojunction. The developed p-n heterojunction photocatalyst proved its ability in utilizing the solar energy for a robust photocatalysis reaction.