Photocatalytic H₂ Generation Using Dewetted Pt-Decorated TiO₂ Nanotubes: Optimized Dewetting and Oxide Crystallization by a Multiple Annealing Process

In the present work we use TiO 2 nanotube arrays, deposit onto them a thin layer of Pt, dewet the Pt to nanoparticles, and use the structures as photocatalyst to generate H 2 . In order to achieve a maximum H 2 -generation efficiency, on the one hand an optimal thermal dewetting of the Pt layer is needed (this requires an oxygen-free heat treatment), and on the other hand an optimal crystallization of the TiO 2 nanotubes into a suitable crystalline oxide is required (achieved by annealing in an O 2 -containing environment). To combine the two requirements, we provide an adequate multiple annealing treatment under reducing and oxidizing conditions and obtain Pt-nanoparticle-decorated TiO 2 nanotubes, composed of an anatase–rutile mixed phase, that show a significantly enhanced photocatalytic H 2 generation ability compared to tube layers that underwent any single-step annealing process.