1：Experimental Design and Method Selection:

A rapid microwave-assisted solvothermal method was employed to fabricate BiOI/SrTiO3 heterostructures. The structure and morphology of the BiOI/SrTiO3 samples could be tailored by changing the ratio of BiOI to SrTiO

2：Sample Selection and Data Sources:

The SrTiO3 fibers were synthesized according to a previously reported electrospinning method. Different amounts of Bi(NO3)3 were added into ethylene glycol, followed by the addition of SrTiO3 fibers. Potassium iodide (KI) was then slowly added to the solution with continuous stirring. The solution was then subjected into a microwave reactor at 150 °C for 15 min at a constant power (700 W).

3：List of Experimental Equipment and Materials:

Titanium(IV) tert-butoxide, strontium acetate, acetic acid, poly(vinylpyrrolidone), ethanol, Bi(NO3)3, potassium iodide, microwave reactor, X-ray diffractometer, transmission electron microscopy, scanning electron microscopy, N2 adsorption–desorption isotherms, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopic analysis, zeta potential analyzer.

4：Experimental Procedures and Operational Workflow:

The as-spun fibers were collected and subsequently heat-treated at 900 °C for 2 h with a ramp rate of 5 °C/min. The yielding products were labeled as ES. To decorate BiOI onto the as-synthesized ES samples, different amounts of Bi(NO3)3 were added into ethylene glycol, followed by the addition of

5：25 g of ES. Potassium iodide (KI) was then slowly added to the solution with continuous stirring. The solution was then subjected into a microwave reactor at 150 °C for 15 min at a constant power (700 W). Data Analysis Methods:

The photocatalytic reactions were conducted using 0.04 g of these samples suspended in 50 mL of methyl orange dye (MO, 1.22 × 10–4 M) by employing a magnetic stirrer inside a reactor. The light source was a 250 W metal halide lamp equipped with an optical filter (cut-off wavelength of 400 nm) to block the UV irradiation. The degradation rate was determined using a UV–Vis spectrometer at a characteristic wavelength of MO (464 nm).