Two-dimensional/two-dimensional (2D/2D) stacking heterostructures are highly desirable in fabricating efficient photocatalysts because face-to-face contact can provide a maximized interfacial region between the two semiconductors; this largely facilitates the migration of charge carriers. Herein, a WS /graphitic carbon nitride (CN) 2D/2D nanosheet heterostructure decorated with CdS quantum dots (QDs) has been designed, for the first time. Optimized CdS/WS /CN without another cocatalyst exhibits a significantly enhanced photocatalytic H evolution rate of 1174.5 μmol h g under visible-light irradiation (λ>420 nm), which is nearly 67 times higher than that of the pure CN nanosheets. The improved photocatalytic activity can be primarily attributed to the highly efficient charge-transfer pathways built among the three components, which effectively accelerate the separation and transfer of photogenerated electrons and holes, and thus, inhibit their recombination. Moreover, the extended light-absorption range also contributes to excellent photocatalytic efficiency. In addition, the CdS/WS /CN photocatalyst shows excellent stability and reusability without apparent decay in the photocatalytic H evolution within 4 cycles in 20 h. It is believed that this work may shed light on specifically designed 2D/2D nanosheet heterostructures for more efficient visible-light-driven photocatalysts.

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A novel flower-like In2S3/CdIn2S4/In2O3 (ICS) ternary heterostructure (HS) is rationally constructed for the first time by a series of carefully designed procedures. In2O3 nanoflakes are the main constituent units which assemble into a flower-like skeleton structure, and CdIn2S4 nanoparticles are in situ generated on the surface of In2O3 nanoflakes through the transformation of CdS quantum dots (QDs) while In2S3 nanoparticles are in situ produced at the region between CdIn2S4 nanoparticles and In2O3 nanoflakes resulting from a synchronous sulfuration procedure. As expected, the rationally designed ICS ternary HSs display significantly enhanced photocatalytic H2 production, especially ICS5 (sulfurized for 5 h) with the highest H2 evolution rate of 20.04 μmol h-1 (10 mg catalyst is used for photocatalytic reaction), which is 26.7 times and 2.6 times higher than that of pure In2O3 (0.75 μmol h-1) and In2S3/In2O3 binary HS (7.88 μmol h-1), respectively. The enhanced photocatalytic activity can be attributed to the multiple interfaces formed in the ICS HSs, including the CdIn2S4-In2O3 interface, the In2S3-In2O3 interface, and the CdIn2S4-In2O3-In2S3 interface, which construct multiple pathways for the transfer of photogenerated charge carriers, effectively promoting the photocatalytic hydrogen production.