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

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 H-2 evolution from aqueous solutions containing sacrificial reagents (Na2S and Na2SO3) under visible light (lambda > 420 nm) even without noble metal co-catalysts. The highest H-2 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. (C) 2015 Elsevier B.V. All rights reserved.