1：Experimental Design and Method Selection:

ZnO was synthesized and modified with noble metals (Pt, Ag, Au) via photodeposition method. Characterization techniques included XRD, XRF, BET, UV–vis DRS, FESEM, TEM, and XPS. Photocatalytic tests were conducted under UV and visible light irradiation for caffeine degradation and TOC removal.

2：Sample Selection and Data Sources:

Samples included unmodified ZnO and ZnO modified with 0.5 wt% and 1 wt% of Pt, Ag, or Au. Caffeine solutions were prepared at specified concentrations.

3：5 wt% and 1 wt% of Pt, Ag, or Au. Caffeine solutions were prepared at specified concentrations. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included Siemens D-501 diffractometer, Panalytical Axios XRF spectrophotometer, Micromeritics ASAP 2010 instrument, Varian Cary 100 UV–vis spectrometer, Hitachi S-4800 FESEM, Philips CM200 TEM, Leybold–Heraeus LHS-10 XPS spectrometer, Pyrex cylindrical reactor, Philips UV and visible lamps (8 W each), Watson Marlow peristaltic pump, Evolution 201 UV–vis spectrophotometer, and TOC analyzer with Pt-Al2O3 catalyst. Materials included Zn(CH3COO)2·2H2O, Na2CO3, H2PtCl6, AgNO3, HAuCl4, isopropanol, caffeine, and distilled water.

4：Experimental Procedures and Operational Workflow:

ZnO synthesis involved precipitation, aging, centrifugation, washing, drying, and calcination. Metal deposition was done under N2 atmosphere with UV–vis lamp irradiation. Photocatalytic tests involved mixing caffeine solution with catalyst, dark adsorption for 2 h, irradiation for up to 4 h, sampling, centrifugation, and analysis of caffeine concentration and TOC.

5：Data Analysis Methods:

Caffeine concentration was measured by UV–vis absorbance at 273 nm. TOC was measured by high-temperature combustion. Data were analyzed to determine degradation rates and removal efficiencies.