Manganese phosphorous trifulfide nanosheets and nitrogen doped carbon dot composites with manganese vacancies for a greatly enhanced hydrogen evolution

• MnPS 3 nanosheets with Mn 2+ vacancies were obtained by the combined exfoliating of NaCl and NMP solvent. • The MnPS 3 -NCDscomposite follows the type-II charge transfer mechanism. • The charge transmission efficiency is accelerated by Mn 2+ defect bands. • The best hydrogen generation rate of 339.63 μmol·g −1 ·h −1 is obtained by the MnPS 3 -NCDs composite. As a novel chalcogenide photocatalyst, MnPS 3 suffered from limited visible light absorption, high photogenerated electron-hole recombination, and low hole oxidation capability due to its high valence band (VB) potential. In this work, the novel MnPS 3 nanosheets-Nitrogen-doped carbon dots (NCDs) composites were fabricated by immobilizing NCDs with terminal amine groups on Na + intercalated MnPS 3 nanosheets for a greatly enhanced photocatalytic hydrogen production activity. MnPS 3 nanosheets of 400 nm with Mn 2+ vacancies are produced in high yield by NaCl intercalation and subsequent exfoliation in N-methylpyrrolidone (NMP). NCDs with 5 nm are evenly loaded on the surface of MnPS 3 nanosheets of 400 nm via strong chemical interactions of ammonium sulfate salts formed at the interface. The MnPS 3 -NCDs composites exhibit enhanced light absorption at 500∼600 nm, reduced charge recombination and notably promoted photocatalytic activity in relative to neat MnPS 3 nanosheets. MnPS 3 -NCDs composite with the NCDs content of 16.5% possessed the highest photocatalytic hydrogen evolution rate of 339.63 μmol·g −1 ·h −1 with good cycling stability, which is 9.17 times that of exfoliated MnPS 3 nanosheets. The type-II MnPS 3 -NCDs heterojunction is conducive to the efficient interfacial carrier transport and the significantly improved photocatalytic hydrogen generation activity. Our work confirmed that the non-toxic MnPS 3 could possess photocatalytic performance comparable to CdS, which will be promising to become an attractive visible-light driven photocatalyst in environmental purification and energy applications.