Double-Side Cocatalytic Activation of Anodic TiO${}_2$ Nanotube Membranes with Sputter-Coated Pt for Photocatalytic H${}_2$ Generation from Water-Ethanol Mixtures

Abstract

Self-standing TiO${}_2$ nanotube layers in the form of membranes are fabricated by self-organizing anodization of Ti metal and a potential shock technique. The membranes were then decorated by sputtering different Pt amounts i) only at the top, ii) only at the bottom or iii) at both top and bottom of the tube layers. The Pt-decorated membranes are transferred either in tube top up or in tube top down configuration onto FTO slides and investigated after crystallization as photocatalysts for H${}_2$ generation using either front or back-side light irradiation. Double-side Pt-decoration of the tube membranes leads to higher H${}_2$ generation rates (independent of tube and light irradiation configuration) compared to membranes decorated at only one side with similar overall Pt amounts. The results suggest that this effect is not ascribed to the overall amount of Pt cocatalyst as such but rather to its distribution at both tube extremities. This leads to optimized light absorption and electron diffusion/transfer dynamics: the central part of the membranes act as light harvesting zone and electrons therein generated can diffuse towards the Pt/TiO${}_2$ active zones (tube extremities) where they can react with the environment and generate H${}_2$ gas.

References in corpus (4)

• TiO2 nanotubes: N-ion implantation at low-dose provides noble-metal-free photocatalytic H2-evolution activity
• Noble metals on anodic TiO2 nanotubes mouths: Thermal dewetting of minimal Pt co-catalyst loading leads to significantly enhanced photocatalytic H2 generation
• Photocatalytic H2 generation using dewetted Pt-decorated TiO2 nanotubes - Optimized dewetting and oxide crystallization by a multiple annealing process
• Topographical study of TiO2 nanostructure surface for photocatalytic hydrogen production

Cited by in corpus (1)

• Compositional gradients in sputtered Ti-Au alloys: Site-selective Au-decoration of anodic TiO${}_2$ nanotubes towards enhanced photocatalytic H${}_2$ evolution