1：Experimental Design and Method Selection:

A hydrothermal method was used with sodium citrate as a structure-directing agent to synthesize BiOCl hierarchical microrods. The method was chosen for its ability to control morphology and structure.

2：Sample Selection and Data Sources:

Samples were prepared with varying amounts of sodium citrate (0 g, 0.05 g, 0.1 g, 0.2 g) to study the effect on structure and photocatalytic activity. Dyes (MO, RhB, phenol) were used as pollutants.

3：05 g, 1 g, 2 g) to study the effect on structure and photocatalytic activity. Dyes (MO, RhB, phenol) were used as pollutants. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included autoclave, X-ray diffractometer (Rigaku D/max-γ A), SEM (Hitachi S-4800), TEM and HRTEM (JEOL-2010), UV-vis spectrophotometer (UV-2450), BET surface area analyzer, PL spectrophotometer (FLS920), EIS instrument (CHI660D), and Xe lamp (CEL-HXF300F). Materials included Bi(NO3)3·5H2O, KCl, sodium citrate, dyes, scavengers (ammonium oxalate, p-benzoquinone, t-butanol).

4：Experimental Procedures and Operational Workflow:

Bi(NO3)3·5H2O and KCl were dissolved in water, sodium citrate added, mixture stirred, transferred to autoclave, heated at 160°C for 12 h, cooled, washed, and dried. Photocatalytic tests involved dispersing catalyst in dye solution, stirring in dark for equilibrium, irradiating with Xe lamp, sampling at intervals, and analyzing with UV-vis spectroscopy. Trapping experiments used scavengers.

5：Data Analysis Methods:

XRD for phase identification, SEM and TEM for morphology, UV-vis DRS for optical properties, BET for surface area, PL for charge separation, EIS for electrochemical properties, and degradation curves for photocatalytic efficiency.