1：Experimental Design and Method Selection:

The synthesis involved a hydrothermal process to prepare CQDs modified Cs4PW11O39Fe(Ⅲ)(H2O) photocatalysts. The phase structure, morphology, optical and electronic properties were characterized by XRD, SEM, TEM, DRS, and surface photovoltage tests.

2：Sample Selection and Data Sources:

Samples included pure Cs4PW11Fe and CQDs/Cs4PW11Fe composites with varying CQDs content (1%, 2%, and 3%).

3：List of Experimental Equipment and Materials:

Powder X-ray diffractometer (XRD, Cu-Kα radiation source, D8 Advanced, Bruker, Germany), Fourier transform infrared (FT-IR) spectrometer (Nicolet 6700, Thermo Scientific, USA), ultraviolet-visible spectrophotometer (T10, Beijing General Instrument Co., Ltd., China), thermal field emission scanning electron microscope (SEM, JSM-7100F, JEOL Co., Ltd., Japan), transmission electron microscopy (TEM, Tecnai G2 F20, Holland), N2 adsorption/desorption equipment (ASAP 2420).

4：0). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The photocatalytic properties were evaluated by RhB degradation under visible light. The process included stirring the mixture in dark for adsorption-desorption equilibrium, followed by visible light irradiation and analysis of RhB concentration.

5：Data Analysis Methods:

The degradation efficiency was determined by UV-vis spectrophotometry. Photoelectrochemical tests included surface photovoltage and electrochemical impedance spectroscopy to confirm charge transfer and separation properties.