1：Experimental Design and Method Selection:

The experiment was designed to synthesize Fe-Bi2O3 nanocomposites using a sol-gel method at room temperature, aiming to enhance photocatalytic activity under visible light. Theoretical models include the use of XRD for crystalline structure analysis and UV-vis spectroscopy for band gap determination.

2：Sample Selection and Data Sources:

Samples were prepared with varying EtOH/H2O volume ratios and Bi/Fe molar ratios. Rhodamine B (RhB) was used as a model contaminant for degradation studies.

3：List of Experimental Equipment and Materials:

Materials included ferric chloride, sodium borohydride, bismuth nitrate, absolute ethyl alcohol, sodium dodecyl benzene sulfonate, ammonium carbonate, and Rhodamine B (all from Merck). Equipment included XRD (Shimadzu XRD 6000), SEM (Hitachi S-4800), UV-vis spectrometer (Shimadzu UV-2550), magnetic stirrer, vacuum pump, oven, and muffle furnace.

4：Experimental Procedures and Operational Workflow:

The synthesis involved dissolving ferric chloride in water, adding sodium borohydride, then bismuth nitrate in ethanol, followed by surfactants and pH adjusters. The mixture was stirred, precipitated, washed, dried, and calcined. Photocatalytic tests involved adding catalyst to RhB solution, stirring in dark for equilibrium, then irradiating with light sources (incandescent, natural, dark), and measuring absorbance over time.

5：Data Analysis Methods:

Data were analyzed using XRD for phase identification, SEM for morphology, UV-vis for absorption spectra and band gap calculation via Kubelka-Munk function, and removal efficiency was calculated based on concentration changes using a spectrophotometer.