1：Experimental Design and Method Selection:

The study used hydrothermal synthesis for Bi2O3 and N-modified Bi2O3 particles, followed by drop-casting and annealing to form thin films. Photoelectrochemical measurements, including linear sweep voltammetry and chronoamperometry, were conducted to assess water oxidation and dye decoloration.

2：Sample Selection and Data Sources:

Bismuth nitrate and urea were used as precursors; samples were prepared with and without nitrogen modification. Data were collected from UV-vis spectroscopy, XRD, SEM, EDS, and electrochemical tests.

3：List of Experimental Equipment and Materials:

Equipment includes Autolab 302 PG-stat, Xe-lamp, monochromator, UV-vis spectrophotometer, XRD, SEM, and EDS. Materials include Bi(NO3)3, urea, FTO-coated glass, and Rhodamine-B dye.

4：Experimental Procedures and Operational Workflow:

Hydrothermal synthesis at 160°C for 20 hours, drop-casting on FTO, annealing at 600°C, electrochemical measurements in buffer solutions under illumination, and photocatalytic dye degradation tests.

5：Data Analysis Methods:

Band gap calculation from UV-vis spectra using Tauc plot, crystallite size from XRD using Scherrer equation, carrier density from Mott-Schottky plots, and kinetic analysis for dye decoloration.