Photocatalytic H₂ Evolution: Dealloying as Efficient Tool for the Fabrication of Rh‐decorated TiO₂ Nanotubes

Abstract

Abstract In this work, we report on a facile and novel method for decorating titanium dioxide (TiO 2 ) nanotubes with Rh nanoparticle‐nanonetworks that act as co‐catalysts in photocatalytic H 2 generation. In a first step, a Ti−Rh (0.2 at%) alloy is etched in Kroll's solution leading to a dealloyed surface decorated with a Rh nanoparticle‐network of adjustable geometry and loading. By subsequent anodization of the alloy samples, Rh:TiO 2 nanotubes can be grown where the tube mouths are strongly decorated with the Rh nanoparticle network (RhNw). As evident from X‐ray photoelectron spectroscopy (XPS) analysis, these Rh oxide Nws are converted to metallic Rh under UV irradiation. As a result, with time a steady increase of the H 2 evolution from the RhNw decorated TiO 2 nanotubes is observed. Nanotubes carrying RhNw yield in photocatalytic experiments a 5‐times higher H 2 evolution activity in comparison with nanotubes decorated by conventional Rh‐sputtering (the same loading), and show a 228 times higher activity than pristine TiO 2 nanotubes.