Synergistic modulation on atomic-level 2D/2D Ti3C2/Svac-ZnIn2S4 heterojunction for photocatalytic H2 production

The photocatalytic hydrogen evolution (PHE) offers a promising and sustainable route to fuels and feedstocks from solar energy. Ti 3 C 2 MXene as a highly active and stable earth-abundant material has been employed in photocatalytic hydrogen production due to its excellent conductivity and effective activation of H 2 O molecules. Herein, a synergistic strategy, via introducing atomic-thickness Ti 3 C 2 MXene to tune the defect structure of the ultrathin ZnIn 2 S 4 nanosheets, is reported to improve the PHE activity. By using microstructure characterization and DFT calculation, we reveal the generation of sulfur vacancies (S vac ) on the photocatalysts and the improvement of adsorption property for reactant H 2 O molecules at the surface of ultrathin 2D/2D Ti 3 C 2 / S vac -ZnIn 2 S 4 heterojunction. During the reaction, the synergies between sulfur vacancies and Ti 3 C 2 MXene affect the absorption of light, the separation of carriers, and the reaction of H 2 O molecules, thus improving the PHE rate up to 1435.31 μmol·g −1 ·h −1 with 6.3 times higher than that of S vac -ZnIn 2 S 4 nanosheets (229.16 μmol·g −1 ·h −1 ). This work stresses the great importance of synergistic modulation for promoting photocatalytic hydrogen evolution.