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In this work, a 2D hybrid CdS nanosheets(NSs)/MoS 2 layered heterojunctions were successfully synthesized by a two-step hydrothermal method and subsequent ultrasonic treatment. The results showed that the loading ultrathin MoS 2 NSs as co-catalysts could significantly boost the photocatalytic H 2 -evolution activity of CdS NSs. It is demonstrated that the optimized 2D CdS NSs/MoS 2 (1.0 wt%) layered heterojunctions could achieve the highest photocatalytic H 2 -evolution activity of 1.75 mmol g −1 h −1 from an aqueous solution containing sulfide and sulfite under visible light, which is 2.03 times as high as that of the pristine CdS NSs. It is believed that the deposition of ultrathin MoS 2 NSs and intimate 2D–2D coupling interfaces are mainly responsible for the excellent H 2 -evolution performance of 2D CdS NSs/MoS 2 layered heterojunctions, owing to the effectively promoted separation and transportation of charge carriers and the enhanced following surface H 2 -evolution kinetics. Interestingly, the lactic acid and formic acid have also been demonstrated to be better sacrificial reagents than the Na 2 S/Na 2 SO 3 , for the photocatalytic H 2 evolution over the 2D CdS NSs/MoS 2 layered heterojunctions. It is hoped that the strategy of 2D–2D interfacical coupling based on CdS NSs can become a general strategy to improve the H 2 -evolution activity over various kinds of conventional semiconductor NSs. [ABSTRACT FROM AUTHOR]

In this report, g-C 3 N 4 -based photocatalysts with dual co-catalysts of amorphous NiS and carbon black were firstly synthesized through a facile two-step process. The g-C 3 N 4 /carbon black/NiS composite photocatalyst were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV–vis), N 2 adsorption, photoluminescence (PL) spectra and transient photocurrent responses. The photocatalytic activities for photocatalytic hydrogen evolution under visible light irradiation ( λ ≥ 420 nm) were measured using an aqueous solution containing triethanolamine as an electron donor. Moreover, the results showed that the ternary g-C 3 N 4 photocatalyst loaded by 0.5 wt% carbon black and 1.5 wt% NiS could achieve the highest H 2 -production rate of 992 μmol g −1 h −1 under visible-light irradiation (>420 nm), which is about 2.51 times higher than that of the corresponding binary g-C 3 N 4 /1.5% NiS photocatalyst. It is believed that the enhanced photocatalytic H 2 -evolution activities could be attributed to the excellent synergetic effect between the carbon black and NiS as co-catalysts on the surface of g-C 3 N 4 , leading to the improved visible light absorption, promoted charge separation and enhanced the following H 2 -evolution kinetics. This work would not only demonstrate the promising potentials of carbon black as co-catalyst for applications in visible-light H 2 generation, but also offer a new insight into the construction of highly efficient and stable g-C 3 N 4 -based hybrid semiconductor nanocomposites with dual co-catalysts for diverse photocatalytic applications. [ABSTRACT FROM AUTHOR]