1：Experimental Design and Method Selection:

The photocatalysts were synthesized by a two-step hydrothermal method from the corresponding precursors. The effect of La (0.05 - 2 mol%) and GO (5 m%) content on the crystal structure, morphology, and photocatalytic activity of TiO2 was investigated.

2：05 - 2 mol%) and GO (5 m%) content on the crystal structure, morphology, and photocatalytic activity of TiO2 was investigated. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Commercial TiO2 P25 (Evonik) and lanthanum nitrate hexahydrate La(NO3)3.6H2O (Vetec) were used as received. Graphene was oxidized by treatment with ozone for 16 h to produce graphene oxide (GO).

3：6H2O (Vetec) were used as received. Graphene was oxidized by treatment with ozone for 16 h to produce graphene oxide (GO). List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: XRD (Philips X 'Pert X-ray diffractometer), SEM (JEOL JSM-6390LV), TEM (JEM-1011), UV-visible DRS (Tensor 27 spectrophotometer), photoluminescence (Varian Eclipse spectrophotometer), and EPR (Bruker ESP 300E spectrometer).

4：Experimental Procedures and Operational Workflow:

The photocatalysts were prepared by suspending TiO2 P25 and lanthanum nitrate in an ethanol/water solution, sonicating, mixing with GO suspension, hydrothermal treatment at 120 °C for 3 h, drying, grinding, and thermal treatment at 600 °C.

5：Data Analysis Methods:

The kinetics of MB degradation was analyzed using pseudo-first-order kinetics. The photocatalytic activity was evaluated by the decolorization of methylene blue under UVA light irradiation.