1：Experimental Design and Method Selection:

The study used a sol-gel method for synthesizing photocatalysts, with calcination at different temperatures to observe phase stability and properties. Characterization techniques included PXRD, FESEM, BET, UV-Vis, and PL spectroscopy, and photocatalytic activity was evaluated via phenol degradation under UV light.

2：Sample Selection and Data Sources:

Pure TiO2, ZrO2, and hybrid ZrO2–TiO2 (1:1 molar ratio) photocatalysts were synthesized. Phenol solutions at 10 ppm and 40 ppm concentrations were used for degradation tests.

3：List of Experimental Equipment and Materials:

Materials included titanium(IV) isopropoxide (TTIP, 97%), zirconium(IV) propoxide solution (TPZ, 70 wt% in 1-propanol), 2-propanol anhydrous (99.5%), nitric acid (70%), phenol (GR for analysis), deionized water. Equipment included a portable pH meter (HQ11d, HACH), magnetic stirrer, furnace (Nabertherm GmbH), PXRD (D/max rB 12 kW, Rigaku @ D5000, Siemens), FESEM (Zeiss Crossbeam 340), BET surface analyzer (Thermo Scientific), UV-Vis spectrometer (Perkin Elmer LAMBDA 1050), PL spectrometer (Perkin Elmer LS55), HPLC system (Agilent Technologies 1220 Infinity LC), UV-A lamp (FL8BLB, Sankyo Denki Co., Ltd.), UVX radiometer (UVP Inc.) with UV-A sensor (UVX-36, UVP Inc.), and PTFE membrane filters.

4：5%), nitric acid (70%), phenol (GR for analysis), deionized water. Equipment included a portable pH meter (HQ11d, HACH), magnetic stirrer, furnace (Nabertherm GmbH), PXRD (D/max rB 12 kW, Rigaku @ D5000, Siemens), FESEM (Zeiss Crossbeam 340), BET surface analyzer (Thermo Scientific), UV-Vis spectrometer (Perkin Elmer LAMBDA 1050), PL spectrometer (Perkin Elmer LS55), HPLC system (Agilent Technologies 1220 Infinity LC), UV-A lamp (FL8BLB, Sankyo Denki Co., Ltd.), UVX radiometer (UVP Inc.) with UV-A sensor (UVX-36, UVP Inc.), and PTFE membrane filters. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Photocatalysts were synthesized by mixing precursors in solvents, adjusting pH, stirring, aging, evaporating at 200°C, drying at 105°C, and calcining at 500, 600, or 700°C. Characterization involved PXRD for crystal structure, FESEM for morphology, BET for surface area, UV-Vis for band gap, PL for electron-hole separation. Photocatalytic tests involved dispersing photocatalysts in phenol solution, establishing adsorption-desorption equilibrium in dark for 120 min, irradiating with UV light, sampling every 30 min for 4 h, filtering, and analyzing with HPLC.

5：Data Analysis Methods:

Crystallite size was calculated using Debye-Scherrer's equation. Band gap energy was estimated from UV-Vis data using Kubelka-Munk theory and Tauc's plot. Phenol degradation percentage was calculated based on concentration changes over time.