Vacuum-Treated Brown Mesoporous TiO₂ Microspheres with Tailored Defect Structures for Enhanced Photoresponsive Properties

Mesoporous TiO2 microspheres with a large surface area were synthesized via a hydrothermal reaction using titanium glycolate. The samples were subsequently subjected to different vacuum oven treatment times (2, 4, 6, and 8 hours), resulting in Ti³⁺ self-doping. Comprehensive characterization was performed using transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The synthesized TiO2 microspheres exhibited significantly enhanced photocurrent and efficient photocatalytic activity under visible light irradiation, demonstrating their potential for applications in solar-driven water splitting. The results highlight the influence of Ti³⁺ self-doping on improving the photoactivity and photosensitivity of the material.