Microfluidic photocatalysis with defect-engineered TiO2

• Amorphous TiO 2 film with rich defects was prepared by reactive PVD. • {004} facet orientational anatase film with high charge transfer was prepared. • Microfluidic reactor intensify process marvelously. • Reactive O 2 flux plays vital role on TiO 2 film structure • Synergetic defect and carrier dynamic controlling contribute high film activity. Developing immobilized film photocatalysts that purify water without post-separation remains challenging. Herein, we report the design and fabrication of a glass-based photocatalytic microfluidic reactor (MFR) integrated with immobilized titanium dioxide (TiO 2 ) photocatalytic coatings for the efficient degradation of organic pollutants. Amorphous TiO 2 films and crystalline TiO 2 films with preferential {004} facet orientation were synthesized using a reactive electron beam evaporation deposition method. The films were comprehensively characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-vis) spectroscopy, and photoluminescence (PL) spectroscopy. Photocatalytic degradation experiments employing methyl orange (MO) solution were performed within the MFR to evaluate performance. Under optimal conditions and UV irradiation, 90% discoloration of MO was achieved within 1.5 min, achieving a rate that is approximately 80-fold higher than that in a conventional batch reactor. The discoloration kinetics adhered to a pseudo-first-order model, and the immobilized catalyst displayed exceptional stability over repeated cycles. This study highlights the critical roles of surface defects and charge carrier dynamics in enhancing photocatalytic efficiency and offers a promising strategy for continuous-flow photocatalytic wastewater treatment systems.