1：Experimental Design and Method Selection:

The study employed the Polyacrylamide gel method for synthesizing PbBiO2Br nanosheets, chosen for its novelty in this context. Characterization techniques included XRD, XPS, SEM, TEM, and UV-vis absorption spectra to analyze properties. Photocatalytic activity was tested under visible light.

2：Sample Selection and Data Sources:

Samples were synthesized from commercially available materials: Bi(NO3)3·5H2O, Pb(NO3)2·3H2O, cetyltrimethylammonium bromide (CTAB), acrylamide monomer, nitric acid, and aqueous ammonia. Methylene blue (MB) aqueous solution (20 mg/L) was used for degradation tests.

3：List of Experimental Equipment and Materials:

Equipment included a magnetic stirrer, thermostat drier, test tube furnace, field-emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) with ESCALAB 250Xi, UV-vis spectrophotometer (UV-3600), and materials as listed.

4：Experimental Procedures and Operational Workflow:

For synthesis, precursors were dissolved, pH adjusted, acrylamide added and polymerized at 90°C, gel dried at 120°C for 24h, ground, and calcined at 450°C for 3h. Photocatalytic tests involved irradiating MB solution with the catalyst under visible light, with details in supplementary information. Characterization and trapping experiments followed standard protocols.

5：3h. Photocatalytic tests involved irradiating MB solution with the catalyst under visible light, with details in supplementary information. Characterization and trapping experiments followed standard protocols. Data Analysis Methods:

5. Data Analysis Methods: Data from XRD, XPS, SEM, TEM, and UV-vis were analyzed to determine crystal structure, composition, morphology, and optical properties. Photocatalytic efficiency was calculated based on degradation rates, and statistical analysis was implied from the results.