Enhanced visible-light-induced hydrogen evolution from water in a noble-metal-free system catalyzed by ZnTCPP-MoS2/TiO2 assembly

Titanium dioxide is an excellent photocatalyst for photocatalytic hydrogen production but its application is limited by its poor visible light harvesting capability. In this work, a visible-light-responsive photocatalytic hydrogen production system was developed using Zn(II)-5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (ZnTCPP) sensitized MoS2/TiO2 (ZnTCPP-MoS2/TiO2) as photocatalysts. The as-prepared composite photocatalysts have apparent adsorption in visible light region, making them active for visible-light-induced hydrogen evolution. Even without noble metals, ZnTCPP-MoS2/TiO2 photocatalyst loaded with 1.00 wt% MoS2 shows the highest H-2 production rate of 10.2 mu mol h(-1), and the turnover number (TON) with respect to ZnTCPP dye reaches 261 after visible light irradiation for 12 h. The highest H-2 production rate of ZnTCPP-MoS2/TiO2 is much higher than that of ZnTCPP-Pt/TiO2, suggesting that MoS2 can act as a more effective cocatalyst than the commonly used platinum. This study presents a noble-metal-free and visible-light-responsive TiO2-based photocatalyst for solar-to-hydrogen conversion. (C) 2015 Elsevier B.V. All rights reserved.