Thin MoS2 on TiO2 nanotube layers: An efficient co-catalyst/harvesting system for photocatalytic H2 evolution

In the presentwork, we decorated MoS2 site-selectively at the top of anodic anatase TiO2 nanotubes (TiNTs). For this we sputter-deposited a thin layer (0.5 to 10 nm) of molybdenum onto the tops of the tubes and converted it to sulfide by a thermal treatment in H2S gas. The converted layers were characterized by SEM, XRD and XPS, and tested as an open-circuit photocatalyst for hydrogen evolution. Under AM1.5 (100 mW/cm(2)) illumination, strongly enhanced H-2 evolution activity can be observed using only a nominal 1 nm thick MoS2 decoration on top of a 6 mu m thick TiNT layer. We ascribe this strong beneficial effect to two factors: (i) the thin molybdenum sulfide on the top acts as an electron transfer mediator, i.e. as an H-2 evolution co-catalyst; and (ii) the underlying tube layer acts as a light-to-electron harvester. (C) 2016 Elsevier B.V. All rights reserved.