1：Experimental Design and Method Selection:

The study employed a chemical co-precipitation method to synthesize Ni1?xZnxO nanocomposites (x = 0.1 to 0.4). The rationale was its low cost and operation at low temperature. Characterization methods included XRD for structural analysis, FTIR for chemical bonding, FESEM for morphology, EDX for elemental composition, and UV-Vis spectroscopy for optical properties. Photocatalytic activity was assessed using dye degradation under sunlight.

2：1 to 4). The rationale was its low cost and operation at low temperature. Characterization methods included XRD for structural analysis, FTIR for chemical bonding, FESEM for morphology, EDX for elemental composition, and UV-Vis spectroscopy for optical properties. Photocatalytic activity was assessed using dye degradation under sunlight. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Samples were prepared with varying zinc concentrations (x = 0.1, 0.2, 0.3, 0.4) in Ni1?xZnxO. Dye solutions of Rose Bengal (RB) and Methylene Blue (MB) at 5 ppm concentration in double distilled water were used as model pollutants.

3：1, 2, 3, 4) in Ni1?xZnxO. Dye solutions of Rose Bengal (RB) and Methylene Blue (MB) at 5 ppm concentration in double distilled water were used as model pollutants. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included Rigaku Ultima IV diffractometer (XRD), nova-nano FESEM 450 (FESEM-EDX), Perkin Elmer Frontier (FTIR), Shimadzu UV-2450 (UV-Vis spectrophotometer). Materials included nickel chloride hexahydrate (Merck), zinc acetate dihydrate (Merck), sodium hydroxide, double distilled water, RB and MB dyes.

4：Experimental Procedures and Operational Workflow:

Synthesis involved dissolving salts in water, mixing, adding NaOH dropwise to form precipitates, aging for 24 hours, decanting, drying at 80°C, crushing, and annealing at 400°C for 4 hours. Photocatalytic tests involved adding 25 mg of sample to 100 ml dye solution, stirring in dark for 30 minutes, exposing to sunlight, collecting aliquots every 10 minutes for 60 minutes, and measuring absorbance with UV-Vis spectrophotometer.

5：Data Analysis Methods:

XRD data analyzed using Debye-Scherrer formula for crystallite size. Optical band gap calculated from Tauc's plot. Dye degradation percentage calculated using formula: % degradation = [(A0 - At)/A0] × 100, where A0 is initial absorbance and At is absorbance at time t.