H₂ Mapping on Pt-Loaded TiO₂ Nanotube Gradient Arrays

Abstract

We describe a rapid screening technique for determining the optimal characteristics of nanophotocatalysts for the production of H₂ on a single surface. Arrays of TiO₂ nanotubes (NTs) with a gradient in length and diameter were fabricated by bipolar anodization, and a perpendicular gradient of Pt nanoparticles (NPs) was generated by the toposelective decoration of the TiO₂ NTs. Photocatalytic hydrogen evolution was locally triggered with a UV laser beam, and the arrays were screened in the <i>x</i> and <i>y</i> directions for spatially resolved kinetic measurements and the mapping of the optimal hydrogen production. By using this technique, we demonstrate the time-efficient and straightforward determination of the tube dimensions and Pt loading for optimized H₂ production. The concept holds promise for generally improving the study of many photoreactions as a function of the physicochemical characteristic of nanophotocatalysts, which renders it highly attractive for the optimization of various important chemical processes