1：Experimental Design and Method Selection:

The study employed a pH-induced precipitation method at room temperature to synthesize Ag2O/TiO2 composites. Photocatalytic oxidation experiments were conducted under visible light irradiation using a photochemical reactor to evaluate the oxidation of As(III). Theoretical models included heterojunction formation and Schottky barrier effects for charge separation.

2：Sample Selection and Data Sources:

Samples included pure Ag2O, TiO2 (Degussa P25), and Ag2O/TiO2 composites with mass ratios of 15%, 30%, and 50%. As(III) solutions were used as model pollutants, with initial concentrations varied from 5 to 20 mg L-1. Data were sourced from laboratory experiments and characterizations.

3：0%. As(III) solutions were used as model pollutants, with initial concentrations varied from 5 to 20 mg L-Data were sourced from laboratory experiments and characterizations. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment: X-ray diffractometer (JapanD/Max 2200PC Rigaku), XPS spectrometer (PHI5000 Versa Probe), TEM (Fei Tecnai G2 F20), UV–vis spectrophotometer (Shimadzu UV-2550), TG analyzer (PTC-10A, Rigaku), photochemical reactor (XPA-VII, Xujiang electromechanical), UV–vis spectrophotometer (Mapada, UV-1800). Materials: TiO2 (Degussa P25), AgNO3, NaOH, deionized water, As(III) solutions, scavengers (Na2C2O4, CH3OH, SOD).

4：0). Materials:

4. Experimental Procedures and Operational Workflow: Preparation of Ag2O/TiO2 composites by dispersing TiO2 in deionized water, adjusting pH to 8.5, adding AgNO3, stirring in dark, adding NaOH, centrifuging, washing, and drying. Photocatalytic experiments involved infusing As(III) and photocatalyst into quartz tubes, dark adsorption for 30 min, visible light irradiation with a 500 W Xe lamp and filters (>420 nm), sampling at intervals, centrifuging, and analyzing supernatants using the molybdenum blue method.

5：Experimental Procedures and Operational Workflow:

5. Data Analysis Methods: Data analysis included XRD for crystalline structure, TEM for morphology, XPS for element composition and valence state, TG for thermal stability, UV–vis DRS for optical properties, and spectrophotometry for As concentrations. Statistical analysis involved duplicate experiments and mean data recording.