1：Experimental Design and Method Selection:

The study employed a simple hydrothermal method to synthesize GQDs/H-TiO2 composites. The methodology focused on the integration of GQDs with H-TiO2 to enhance photocatalytic activity under visible light.

2：Sample Selection and Data Sources:

GQDs were synthesized via a top-down process from three-dimensional graphene network materials (3DGNs), and H-TiO2 was prepared by a template method using melamine formaldehyde microspheres as templates.

3：List of Experimental Equipment and Materials:

Equipment included SEM (JSM-6701F), TEM (JEM-2010), UV–vis spectrophotometer (Shimadzu UV 2550), and a fluorescence spectrometer (Fluoro Max-4). Materials included flame-retardant expandable graphite, concentrated sulfuric acid, phosphoric acid, nitrogen, N, N-dimethylformamide (DMF), hydrogen peroxide (H2O2), glacial acetic acid, potassium permanganate, and tetrabutyl titanate (TBOT, 98%).

4：4). Materials included flame-retardant expandable graphite, concentrated sulfuric acid, phosphoric acid, nitrogen, N, N-dimethylformamide (DMF), hydrogen peroxide (H2O2), glacial acetic acid, potassium permanganate, and tetrabutyl titanate (TBOT, 98%). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The synthesis involved the preparation of GQDs from 3DGNs, the synthesis of H-TiO2 via a template method, and the combination of GQDs with H-TiO2 through a hydrothermal method. Photocatalytic activity was evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation.

5：Data Analysis Methods:

The photocatalytic activity was analyzed by UV–vis absorption spectra, and the photoelectrochemical properties were measured using an electrochemical workstation (CHI 660E).