1：Experimental Design and Method Selection:

The study involved synthesizing Na doped g-C3N4 nanosheets via a mixed-calcination method using melamine and NaCl, followed by characterization and photocatalytic activity tests for oxidative denitrogenation and desulfurization under visible light irradiation with O2 as oxidant.

2：Sample Selection and Data Sources:

Model fuels were prepared by dissolving pyridine or thiophene in n-octane with specific concentrations of N and S elements. Catalysts included pure g-C3N4 and Na doped variants with varying NaCl/melamine ratios.

3：List of Experimental Equipment and Materials:

Equipment included Rigaku D/Max 2400 diffractometer for XRD, ASAP 2420 surface area analyzer for BET, Nicolet Thermo 360 spectrometer for FT-IR, THERMO instrument for XPS, Pyris 1 thermal analyzer for TGA, JEM-2100HR TEM, JSM-7500F SEM, ZetaPALS Brookhaven instrument for zeta potential, JASCO V-770 spectrometer for UV-vis, EDAX Orbis PC for PL, CHI650D electrochemical workstation for photocurrent, 300 W Xe lamp with cut-off filter for light source, Agilent GC-7890B gas chromatograph for analysis, and ICS-600 ion-chromatograph for product analysis. Materials included melamine, NaCl, n-octane, pyridine, thiophene, triethanolamine, dimethyl sulphoxide, and various chemicals for characterizations.

4：Experimental Procedures and Operational Workflow:

Catalysts were prepared by grinding mixtures of melamine and NaCl, calcining at 520°C, washing, and drying. Characterizations involved XRD, BET, FT-IR, XPS, TGA, TEM, SEM, zeta potential, UV-vis, PL, and photocurrent measurements. Photocatalytic tests were conducted by adding catalyst to model fuel, charging with O2, irradiating with visible light, sampling at intervals, and analyzing with GC or ion chromatography.

5：Data Analysis Methods:

Data were analyzed using standard techniques for each characterization method, with photocatalytic activity evaluated based on removal efficiency of contaminants.