1：Experimental Design and Method Selection:

A facile microwave-assisted hydrothermal method was used to synthesize ZnO tetrapods, based on a reported protocol. The photocatalytic activity was assessed under UV-light illumination using Rhodamine B dye as a model pollutant.

2：Sample Selection and Data Sources:

Analytical grade zinc nitrate hexahydrate and hexamethylenetetramine were used as precursors. The ZnO tetrapods were synthesized, centrifuged, washed, and dried.

3：List of Experimental Equipment and Materials:

Equipment includes FESEM (JSM-6700F), TEM (JEOL JEM-2100F), UV-Vis spectrophotometer (Evolution 220), and a 250 W high-pressure Hg lamp. Materials include zinc nitrate hexahydrate, hexamethylenetetramine, ethanol, and Rhodamine B dye.

4：Experimental Procedures and Operational Workflow:

Synthesis involved mixing precursors at 25 mM each for 20 min, followed by centrifugation, washing with ethanol, and drying. Photocatalytic experiments involved adding 50 mg of sample to 100 mL of 1.0 × 10^-5 M RB solution, stirring in dark for 30 min, then exposing to UV light at 10 cm distance, with samples withdrawn every 15 min for UV-Vis analysis after centrifugation.

5：0 × 10^-5 M RB solution, stirring in dark for 30 min, then exposing to UV light at 10 cm distance, with samples withdrawn every 15 min for UV-Vis analysis after centrifugation. Data Analysis Methods:

5. Data Analysis Methods: UV-Vis spectroscopy was used to measure dye concentration at 553 nm. Degradation rate was calculated using I = C/C0 × 100%, and bandgap was estimated using E = hc/λ.