Laser solid-phase synthesis of TiO₂ anatase/rutile homojunctions for efficient photocatalytic hydrogen evolution

Traditional methods for synthesizing TiO₂ homojunctions are complex and challenging in controlling phase composition and junction quality. In this work, we have developed infrared laser solid-phase ablation of anatase TiO₂ nanotubes to address these issues, systematically varying laser parameters to optimize the phase composition and junction quality. The synthesized homojunctions are characterized to understand their structure-activity relationship. The photocatalytic performance shows that the laser-ablated TiO₂ nanostructures with an optimal anatase/rutile ratio of 1:3 exhibit the highest hydrogen production rate of 2388 µmol g^-1h^-1, doubling that of the pristine TiO₂ nanotubes. This enhancement is attributed to the balanced presence of surface oxygen vacancies and Ti³⁺ defects, accompanied with the effective spatial separation of electron-hole pairs induced by the anatase/rutile homojunctions. This study demonstrates a scalable and effective method for hydrogen production via solar energy conversion and expands the application field of pulsed laser synthesis technique.