Highly efficient hydrogen production via water splitting using Pt@MWNT/TiO2 ternary hybrid composite as a catalyst under UV-visible light

Abstract

Platinum nanoparticles (Pt)-supported multi-walled carbon nanotube (MWNT)/titanium dioxide (TiO2) ternary composite was synthesized by a step-wise approach. The MWNT/TiO2 composite was prepared via a sal-gel technique, after which post annealing was applied, and then the Pt nanoparticles were loaded by photo-deposition. This paper reports the enhanced hydrogen production through the application of Pt nanoparticles on photocatalytic water splitting under visible and UV-vis light. The results showed that no appreciable H-2 production was achieved using Pt@MWNT/TiO2 ternary composites as a photocatalyst under visible light, whereas a substantial amount of H-2 was produced under full spectra. The ternary composite with a Pt loading of 1.5 wt% exhibited the highest H-2 production level (435.9 mu mol h(-1)), which was significantly higher than that of pure TiO2 (78.6 mu mol h(-1)) and MWNT/TiO2 composite (235.6 mu mol h(-1)). The efficient hydrogen production activity of the ternary composite can be attributed to the synergetic effect of MWNT and Pt nanoparticles, which enhances the light absorption ability and facilitates a greater charge separation activity. Hence, we report that the appropriate combination of Pt as a co-catalyst can greatly improve the photocatalytic H-2 production performance of MWNT/TiO2 composites. (C) 2014 Elsevier B.V. All rights reserved.