Spectacular Oxygen Evolution Reaction Enhancement through Laser Processing of the Nickel‐Decorated Titania Nanotubes

The selective, laser‐induced modification of the nickel‐decorated titania nanotubes provides remarkable enhancement toward oxygen evolution reaction. Particularly, the irradiation of the laterally spaced crystalline TiO2 nanotubes, results in the formation of the tight closure over irradiated end, preserving their hollow interior. The shape of the absorbance spectra is modulated along with applied energy, and the new absorption band appears at 500 nm, where the local minimum can be found for bare nanotubes. The high‐resolution X‐ray photoelectron spectra indicate the presence of both metallic and hydroxide forms of nickel species. The electrode material treated with 355 nm pulses at 50 mJ cm−2 shows significantly improved current densities in the anodic regime, reaching nearly 300 mA cm−2 while exposed to solar radiation, whereas the untreated sample barely comes to 1.5 mA cm−2 in the same conditions. The tailored titania photoanode also exhibits two orders of magnitude higher donor concentration in comparison to the primary substrate as verified by Mott–Schottky analysis. The electrochemical analysis confirms the key role of laser annealing in enhancing the effectiveness of light‐driven water splitting. Spectacular improvement of the photocatalytic water splitting for the titania‐based electrode is achieved via synergistic effects of nickel decoration and UV laser treatment. In respect to the reference sample, up to 280 times higher current densities are measured, with less than 1% drop in stability over 12 h workload at 10 mA cm−2.