Enhanced Photocatalytic H₂ Generation by Light-Induced Carbon Modification of TiO₂ Nanotubes

Titanium dioxide (TiO₂) is the material of choice for photocatalytic and electrochemical applications owing to its outstanding physicochemical properties. However, its wide bandgap and relatively low conductivity limit its practical application. Modifying TiO₂ with carbon species is a promising route to overcome these intrinsic complexities. In this work, we propose a facile method to modify TiO₂ nanotubes (NTs) based on the remnant organic electrolyte retained inside the nanotubes after the anodization process, that is, without removing it by immersion in ethanol. Carbon-modified TiO₂ NTs (C-TiO₂ NTs) showed enhanced H₂ evolution in photocatalysis under UV illumination in aqueous solutions. When the C-TiO₂ NTs were subjected to UV light illumination, the carbon underwent modification, resulting in higher measured photocurrents in the tube layers. After UV illumination, the IPCE of the C-TiO₂ NTs was 4.4-fold higher than that of the carbon-free TiO₂ NTs.