1：Experimental Design and Method Selection:

The study employed a mechanochemical method for composite preparation, chosen for its simplicity, low cost, and ability to facilitate solid-state reactions without heating. Photocatalytic degradation efficiency was evaluated under visible light illumination.

2：Sample Selection and Data Sources:

Raw materials included nano-TiO2, powder quartz (PQ), and various chemicals for paint formulation. Samples were prepared with different mass ratios of PQ to nano-TiO2 (e.g., 1/1, 2/1, 4/1, 6/1, 8/1) and characterized.

3：List of Experimental Equipment and Materials:

Equipment included a ceramic ball mill (XMCQ-Φ280×290), dispersion machine (SDF-400), vacuum oven (DHG-9070A), SEM (EVO-18), TGA (SDT-Q600), and FT-IR (Spectrum one). Materials included nano-TiO2, PQ, dispersants, antifoaming agents, hydroxyethyl cellulose, styrene-acrylic latex, pH adjusters, and formaldehyde solution.

4：Experimental Procedures and Operational Workflow:

PQ slurry was prepared by milling PQ with water and additives. Nano-TiO2 slurry was prepared separately. These were mixed in predetermined ratios, milled, centrifuged, washed, and dried. Interior paints were formulated with the composite and tested for formaldehyde degradation using standard methods.

5：Data Analysis Methods:

SEM and EDS for morphology and composition, TGA for thermal stability and weight loss analysis, FT-IR for chemical bonding, and DEF calculation based on MBTH method for formaldehyde concentration.