1：Experimental Design and Method Selection:

A sol–gel method was used with tetrabutyl orthotitanate as precursor and activated carbon templates to synthesize nanoscale anatase TiO2 single crystals. The method was chosen for its simplicity and effectiveness in producing mesoporous materials.

2：Sample Selection and Data Sources:

Three types of activated carbon (wood-based, walnut-based, coal-based) were used as templates. Crystal violet dye was selected as the target pollutant for photocatalytic degradation tests.

3：List of Experimental Equipment and Materials:

Materials included tetrabutyl orthotitanate, anhydrous alcohol, acetic acid, activated carbons, and crystal violet. Equipment included X-ray diffractometer, transmission electron microscope, surface-area analyzer, FT-IR spectrometer, X-ray photoelectron spectrometer, fluorescence spectrophotometer, cyclic voltammetry setup, UV lamp, spectrophotometer, and centrifuge.

4：Experimental Procedures and Operational Workflow:

The synthesis involved dissolving TBOT in alcohol, adding AC, adding acetic acid and water mixture, stirring, centrifuging, washing, drying, and calcining. Photocatalytic experiments involved adding photocatalyst to CV solution, stirring in dark, irradiating with UV light, sampling at intervals, centrifuging, and measuring CV concentration.

5：Data Analysis Methods:

XRD for crystal phase and size, TEM for morphology, BET for surface area and pore volume, FT-IR for functional groups, XPS for surface composition, PL for charge recombination, cyclic voltammetry for conductivity, and UV-Vis spectroscopy for degradation kinetics.