Novel photocatalysts -CdSe quantum dots (QDs)/g-C 3 N 4 - were successfully constructed. The structure, chemical composition, and optical properties of the prepared samples were investigated via a series of characterization techniques. The results indicated that CdSe QDs/g-C 3 N 4 photocatalysts exhibited remarkably enhanced photocatalytic activity for visible-light-induced H 2 evolution compared to pristine g-C 3 N 4 and CdSe QDs and addition of 13.6 wt % CdSe QDs into the composite photocatalyst generated the highest H 2 production rate. The enhanced photocatalytic performance of CdSe QDs/g-C 3 N 4 can be attributed to the synergistic effects of excellent visible absorption and high charge separation efficiency from the heterostructure. This work could not only provide a facile method to fabricate semiconductor QDs-modified g-C 3 N 4 photocatalysts but also contribute to the design for heterostructures.

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Alkaline-earth metal Ca2+ modified CdS nanocrystals are firstly designed for highly efficient H2 evolution from hydrogen sulfide (H2S) with Na2SO3 as a favourable reaction medium. Advantage of Na2SO3 was revealed...

Photoinduced carrier dynamical processes dominate the optical excitation properties of photocatalysts and further determine the photocatalytic performance. In addition, as the electrons generally possess a faster transfer rate than holes, hole transfer and accumulation are critical, and they play the key efficiency-limiting step during the photocatalytic process. Therefore, a comprehensive understanding of the dynamics of photogenerated holes and their determining factors in the photocatalytic system is highly essential to rationalize the full catalytic mechanism and develop highly efficient photocatalysts, which have not yet been revealed. In this work, the photoinduced charge carrier dynamics in InP/ZnS quantum dots (QDs) capped with long-chain L-typed ligands (oleylamine) and inorganic ligands (sulfide ion (S2−)) were explored. Time-resolved photoluminescence and femtosecond transient-absorption spectroscopy unambiguously confirmed the ultrafast hole transfer from the InP core to S2− ligands. Moreover, by probing the bleach of vibrational stretching of the ligands with transient midinfrared absorption spectroscopy, the hole transfer time was determined to be 4.2 ps. The injected holes are long-lived at the S2− ligands (>4.5 ns), and they can remove electrostatically attached surfactants to compensate for the spatial charge redistribution. Finally, compared with other inorganic ligands such as Cl− and PO43−, S2− balances the ionic radii and net charge to ensure the optimal condition for charge transfer. Such observation rationalizes the excellent photocatalytic H2 evolution (213.6 µmol mg−1 within 10 h) in InP/ZnS QDs capped with S2− compared with those capped with other ligands and elucidates the role of surface ligands in the photocatalytic activity of colloidal QDs.