Construction of novel S/CdS type II heterojunction for photocatalytic H2 production under visible light: The intrinsic positive role of elementary α-S

Traditional view points that the photocorrosion product sulfur clusters have negative effect on the activity of CdS system. Differently, in this paper, little amount of crystalline elementary alpha-sulfur (alpha-S) nanoparticles were loaded on the surface of CdS nanorods and resulted in enhanced photocatalytic H-2 production activity under visible light (lambda > 420 nm). The photocatalytic H-2 production over 10% S/CdS composite was 8.14 mmol and further rose to 30.02 mmol in the presence of K2PtCl6 after 3 h irradiation. In the novel S/CdS system, largely improved separation efficiency of photoexcited charges were achieved through the heterojunction interface role between alpha-S nanoparticles and CdS nanorods. The matching type II energy band structure ensures that alpha-S could quickly trapped electrons from the host CdS nanorods for reducing H+ to produce H-2. After 10 cycles experiment, S/CdS still kept excellent photocatalytic H-2 production activity. This study clearly demonstrates the intrinsic promoting effect of alpha-S in CdS photo catalyst even in other metal sulfide systems for enhancing photocatalytic H-2 production activity under visible light. (C) 2017 Elsevier B.V. All rights reserved.