1：Experimental Design and Method Selection:

The study used the successive ionic layer adsorption and reaction (SILAR) method to deposit BiOI nanosheets/nanoflowers on TiO2 nanotube arrays (TiO2 NTs). The rationale was to control the morphology and interface connection by varying SILAR deposition cycles (3, 7, 9, and 13 cycles) to enhance visible light response and charge carrier transportation. Theoretical models included p-n heterojunction formation for efficient electron-hole separation.

2：Sample Selection and Data Sources:

Samples were prepared on Ti substrates. TiO2 NTs were fabricated by anodization, and BiOI was deposited using Bi(NO3)3·5H2O and KI solutions. Selection criteria included varying SILAR cycles to study morphology and performance.

3：List of Experimental Equipment and Materials:

Equipment: Scanning electron microscopy (Hitachi SU 8010, Japan), UV-Vis spectrophotometer (Cary 60), electrochemical workstation (CHI660E, China), solar simulator with 500 W Xe lamp (CEL-S500). Materials: Ti substrate, bismuth nitrate (Bi(NO3)3·5H2O), potassium iodide (KI), Na2SO4, dyes (MO, RhB, MB), Cr(VI) solution, scavengers (t-BuOH, BQ, EDTA-2Na, DMSO).

4：0). Materials:

4. Experimental Procedures and Operational Workflow: TiO2 NTs were prepared by anodization. For BiOI deposition: immerse TiO2 NTs in Bi(NO3)3 solution for 30 s, rinse with deionized water, immerse in KI solution for 2 min, rinse, repeat for cycles (3, 7, 9, 13), calcinate at 300°C for 2.5 h. Characterization included SEM, XPS, UV-Vis DRS. PEC activity measured under solar irradiation with fixed potentials, using three-electrode system.

5：Experimental Procedures and Operational Workflow:

5. Data Analysis Methods: PEC degradation efficiencies calculated from UV-Vis absorption at specific wavelengths. Kinetic analysis used pseudo-first-order models. Active species identified with scavenger experiments. Photocurrent and photovoltage measured electrochemically.