1：Experimental Design and Method Selection:

The study involved applying poly(alkyl siloxane) coatings with and without 0.5 wt% nano-ZnO to sandstone samples, comparing them with uncoated sandstone. Methods included colorimetry, X-ray diffraction, SEM, mercury intrusion porosimetry, contact angle measurements, water absorption/evaporation tests, and photocatalytic activity assessments using methylene blue degradation under UV irradiation.

2：5 wt% nano-ZnO to sandstone samples, comparing them with uncoated sandstone. Methods included colorimetry, X-ray diffraction, SEM, mercury intrusion porosimetry, contact angle measurements, water absorption/evaporation tests, and photocatalytic activity assessments using methylene blue degradation under UV irradiation. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Green glauconitic sandstone specimens were cut into various sizes (e.g., 50x100x150 mm, 10x10x20 mm, 10x50x100 mm) from quarry blocks, selected based on bulk density similarity. ZnO nanoparticles were synthesized hydrothermally.

3：List of Experimental Equipment and Materials:

Equipment included Bruker D8 Advance diffractometer, Hitachi SU6600 SEM, AutoPore 9500 porosimeter, CINTRA 303 UV-VIS spectrophotometer, MiniScan EZ 4500S spectrophotometer, air brush Fengda BD-182, compressor Fengda AS18-2. Materials included zinc chloride, sodium hydroxide, methylene blue, poly(alkyl siloxane) Porosil VV plus.

4：Materials included zinc chloride, sodium hydroxide, methylene blue, poly(alkyl siloxane) Porosil VV plus. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Coatings were applied by spraying in three layers. Samples were analyzed for phase composition, surface morphology, pore distribution, hydrophobicity (via contact angle), water absorption/evaporation dynamics, and photocatalytic activity (using methylene blue degradation and colorimetry).

5：Data Analysis Methods:

Data were analyzed using ImageJ for contact angles, linear regression for absorption curves, and statistical methods for standard deviations. Color differences were calculated using DE* formula.