1：Experimental Design and Method Selection:

A two-step solvothermal synthesis method was employed to prepare the TiO2 HHMs/rGO hybrid. The first step involved the synthesis of anatase TiO2 hollow hierarchical microspheres (TiO2 HHMs) using a solvothermal method. The second step involved the preparation of the TiO2 HHMs/rGO hybrid by integrating TiO2 HHMs with reduced graphene oxide (rGO) through another solvothermal process.

2：Sample Selection and Data Sources:

Graphene oxide (GO) was synthesized using a modified Hummers’ method. Anatase TiO2 HHMs were synthesized by dissolving Ti(SO4)2 in ethanol, adding CTAB and HF, and then undergoing solvothermal treatment.

3：List of Experimental Equipment and Materials:

Equipment included a Teflon autoclave, centrifuge, oven, XRD diffractometer, SEM, TEM, BET surface area analyzer, FT-IR spectrometer, TG analyzer, XPS system, and UV–vis spectrophotometer. Materials included Ti(SO4)2, ethanol, CTAB, HF, GO, RhB, and Degussa P

4：Experimental Procedures and Operational Workflow:

The TiO2 HHMs were synthesized and then hybridized with rGO in a second solvothermal process. The photocatalytic activity was evaluated by degrading RhB under simulated solar light irradiation.

5：Data Analysis Methods:

The photocatalytic activity was determined by measuring the concentration of RhB solution at 554 nm wavelength using a UV–vis spectrophotometer.