1：Experimental Design and Method Selection:

The study involved the synthesis of a 0D/2D hybrid material through a facile chemical reaction and subsequent low-temperature calcination. The methodology aimed to enhance photo-Fenton activity by improving charge separation and exposing more active sites.

2：Sample Selection and Data Sources:

The samples included pristine g-C3N4 nanosheets and Fe2O3 QDs/g-C3N4 hybrids with varying g-C3N4 contents. Data were acquired through various characterization techniques including XRD, FT-IR, SEM, TEM, XPS, UV–vis DRS, PL, and photoelectrochemical measurements.

3：List of Experimental Equipment and Materials:

Equipment used included a Rigaku SmartLab diffractometer, MKS6030 spectrometer, Shimadzu UV-3600 spectrophotometer, Escalab 250 Xi system, Hitachi SU8010 FE-SEM, JEM-2100F TEM, Zetasizer Nano-ZS90, Fluorolog-3, S4 Pioneer spectrometer, and an electrochemical workstation (CHI 920). Materials included urea, ferric chloride hexahydrate, ammonium hydrogen carbonate, ethanol, and hydrogen peroxide.

4：0). Materials included urea, ferric chloride hexahydrate, ammonium hydrogen carbonate, ethanol, and hydrogen peroxide. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The synthesis involved dispersing g-C3N4 NSs in ethanol, adding FeCl3·6H2O and NH4HCO3, stirring, centrifuging, washing, drying, and annealing. Catalytic performance was evaluated by degrading p-nitrophenol under visible light irradiation with H2O

5：Data Analysis Methods:

Data were analyzed using UV–vis spectrophotometry, PL spectra, time-resolved PL decay curves, transient photocurrent performance, IMPS, EIS Nyquist plots, and DPV curves.