1：Experimental Design and Method Selection:

A facile thermal condensation path was used for the synthesis of g-C3N4 nanotubes stuffed with quantum dots. The reaction temperature was controlled to improve the photoluminescence quantum yield.

2：Sample Selection and Data Sources:

5.0 g melamine was used as the precursor, heated at 525 °C for 3 h under air atmosphere.

3：0 g melamine was used as the precursor, heated at 525 °C for 3 h under air atmosphere. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Quartz bottle, muffle furnace, dialysis equipment, Philips powder diffractometer, ESCALAB 250 spectrometer, JEOL JEM-2100F TEM, Nicolet 6700 FTIR spectrometer, Cary Eclipse fluorescence spectrophotometer, Renishaw inVia micro-Raman spectrometer, integrating sphere on an Edinburgh Instruments FLS

4：Experimental Procedures and Operational Workflow:

9 Melamine was heated in a sealed quartz bottle, exfoliated by ultrasonication, purified via dialysis, and dried to obtain powdered samples.

5：Data Analysis Methods:

XRD, XPS, TEM, FTIR, Raman, UV-vis absorption, PL and PLE spectra, and absolute QYs were measured to characterize the samples.