1：Experimental Design and Method Selection:

TiO2 films were deposited by rf reactive magnetron sputtering on various substrates including PET, PI, and quartz with buffer layers (SiO2 or ZTO). The study aimed to optimize deposition conditions for high photocatalytic activity and to investigate the effects of buffer layers on preventing polymer degradation.

2：Sample Selection and Data Sources:

Substrates used were 125 μm thick PET sheets, PET sheets coated with 100 nm thick SiO2 or ZTO films, 38 μm thick PI sheets, PI sheets coated with 100 nm thick SiO2 or ZTO films, and synthetic quartz glasses. All films were deposited under optimized sputtering conditions.

3：List of Experimental Equipment and Materials:

Equipment included rf reactive magnetron sputtering systems (L-332S-FH, ANELVA), surface profiler (Sloan Tech, Dektak3), X-ray diffractometer (Shimadzu XRD-6000), transmission electron microscope (JEOL JEM-4010), focused ion beam (JEOL JEM-9310), optical spectrophotometer (Shimadzu UV-3150), contact angle meter (Kyowa Kaimen Kagaku CA-X), atomic force microscope (Shimadzu SPM-9600), and gas chromatograph (Shimadzu GC-8A). Materials included Ti target (

4：99%), Si target (99%), ZTO target (Zn:

Sn=2:1, Sumitomo Chemical), argon (99.99%), oxygen (99.99%), PET sheets, PI sheets, and alkali-free glasses (AN-100, AGC).

5：99%), oxygen (99%), PET sheets, PI sheets, and alkali-free glasses (AN-100, AGC). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: TiO2 films (200 nm thick) were deposited using rf reactive magnetron sputtering with O2 flow ratio fixed at 40%, rf power at 100 W, and total gas pressure at 3.0 Pa. Buffer layers (SiO2 or ZTO, 100 nm thick) were deposited under specific conditions. Additional SiO2 layers were deposited on the outermost surface. Characterization included thickness measurement, XRD analysis, TEM observation, optical transmittance/reflectance measurement, contact angle measurement, AFM analysis, and photocatalytic decomposition evaluation of CH3CHO under UV irradiation.

6：0 Pa. Buffer layers (SiO2 or ZTO, 100 nm thick) were deposited under specific conditions. Additional SiO2 layers were deposited on the outermost surface. Characterization included thickness measurement, XRD analysis, TEM observation, optical transmittance/reflectance measurement, contact angle measurement, AFM analysis, and photocatalytic decomposition evaluation of CH3CHO under UV irradiation. Data Analysis Methods:

5. Data Analysis Methods: XRD patterns were analyzed for crystal structure, TEM images for cross-sectional structure, optical spectra for transmittance and reflectance, contact angles for hydrophilicity, AFM for surface morphology, and gas chromatography for CH3CHO concentration decay.