A novel MoS2 quantum dots (QDs) decorated Z-scheme g-C3N4 nanosheet/N-doped carbon dots heterostructure photocatalyst for photocatalytic hydrogen evolution

A novel MoS2 quantum dots (QDs) decorated g-C3N4 nanosheet/N-doped carbon dots (NCDS) heterojunction photocatalyst was successfully synthesized by thermal polymerization and subsequent solvothermal approach. Under visible light (λ ≥ 420 nm) irradiation, the as-prepared g-C3N4/NCDS/MoS2 composite with 3wt% of MoS2 and 2wt% of NCDS displayed the highest photocatalytic hydrogen evolution activity with a corresponding H2 evolution rate of 212.41μmol g−1 h−1, which was about 53 times higher than that of g-C3N4/MoS2-3%. Moreover, the g-C3N4/NCDS/MoS2 composite exhibited excellent photostability. The enhanced photocatalytic activity of g-C3N4/NCDS/MoS2 composite was predominantly attributed to the formation of Z-scheme heterojunction between g-C3N4 and NCDS, which effectively accelerated the transfer and separation of photogenerated charge carriers. Besides, the introduction of noble metal-free MoS2 co-catalyst further promoted the separation of photogenerated charge carriers and provided more active sites for H2 evolution reaction. The advantages of superior photocatalytic activity and excellent stability endowed a promising potential for g-C3N4/NCDS/MoS2 composite to apply in photocatalytic fields.