Novel visible-light driven Mn0.8Cd0.2S/g-C3N4 composites: Preparation and efficient photocatalytic hydrogen production from water without noble metals

•g-C3N4 sheets supported Mn0.8Cd0.2S were synthesized by a hydrothermal method.•The obtained composites exhibited excellent photocatalytic activity and stability.•The optimal composite showed a hydrogen evolution rate of 4.0 mmol h−1 g−1.•An efficient charge separation and transfer was observed in the composites.

A series of novel visible light-responsive Mn0.8Cd0.2S/g-C3N4 hybrid materials with different g-C3N4 contents were synthesized via a facile hydrothermal method. The obtained Mn0.8Cd0.2S/g-C3N4 composites displayed highly efficient photocatalytic activities for H2 evolution from aqueous solutions containing sacrificial reagents (Na2S and Na2SO3) under visible light (λ > 420 nm) even without noble metal co-catalysts. The highest H2 evolution rate of 4.0 mmol h−1 g−1 (with an apparent quantum efficiency of 4.1% at 420 nm) was achieved on the Mn0.8Cd0.2S/g-C3N4 (10 wt%) sample, which was about 3.40 times higher than that of pure Mn0.8Cd0.2S. The enhanced photocatalytic activity of Mn0.8Cd0.2S/g-C3N4 composites should be attributed to the well-matched band structure and intimate contact interfaces between Mn0.8Cd0.2S and g-C3N4, which led to the effective transfer and separation of the photogenerated charge carriers. In addition, the Mn0.8Cd0.2S/g-C3N4 photocatalysts showed good stability during the photocatalytic water splitting to hydrogen under visible light. A possible mechanism of the enhanced photocatalytic activity of Mn0.8Cd0.2S/g-C3N4 was also proposed.

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