Fabrication of 2D SnS₂/g-C₃N₄ heterojunction with enhanced H₂ evolution during photocatalytic water splitting

In this work, the 2D SnS₂/g-C₃N₄ heterojunctions were successfully prepared by heating the homogeneous dispersion of SnS₂ nanosheets and g-C₃N₄ nanosheets using a microwave muffle. SEM, TEM and HRTEM images indicated that the SnS₂ nanosheets were loaded on the surface of the g-C₃N₄ nanosheets. The UV-vis spectra show that the absorption intensity of the as-prepared samples was increased and the absorption range was also extended from 420 nm to approximately 600 nm. The H₂ production rate over 5 wt% SnS₂/g-C₃N₄ can reach 972.6 μmol·h^-1·g^-1 under visible light irradiation (λ > 420 nm) using TEOA as the sacrifice agent and Pt as the electron trap, which is 2.9 and 25.6 times higher than those of the pristine g-C₃N₄ and SnS₂, respectively. According to the obtained PL spectra, photocurrent and EIS spectra, the enhanced performance for H₂ generation over the heterojunctions is primarily ascribed to the rapid charge transfer arising from the suitable band gap positions leading to an improved photocatalytic performance. The recycling experiments indicated that the as-prepared composites exhibit good stability in H₂ production. Additionally, a possible enhanced mechanism for H₂ evolution was deduced based on the results obtained by various characterization techniques.