1：Experimental Design and Method Selection:

The study involved synthesizing SNGODs through sequential annealing of graphene oxide with sulfur and ammonia, exfoliation into dots, and autoclaving in ammonia solution. Photocatalytic activity was assessed in a gas-enclosed system under visible light irradiation.

2：Sample Selection and Data Sources:

Catalysts included SNGODs, NGODs (nitrogen-doped only), and SGODs (sulfur-doped only) for comparison. Sugar and glucose aqueous solutions (0.35 mol L?1) were used as biomass substrates.

3：35 mol L?1) were used as biomass substrates. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included XPS (AXIS Ultra DLD, Kratos), TEM (Jeol 2100F), Raman microscope (DXR, Thermo Fisher), FTIR spectrometer (Nicolet 6700, Thermo Fisher), UV-Vis spectrophotometer (Hitachi U-4100), UPS (Sigma Probe, Thermo VG Scientific), EPR spectrometer (Magnettech MS5000), PL spectrophotometer (F-700, Hitachi), spectrofluorometer (FS5, Edinburgh Instruments), gas chromatography (Hewlett-Packard 7890), and photocatalytic reaction system with Xenon lamp (Oriel Instruments, model 66901). Materials included natural graphite powder (Bay carbon, SP-1), sulfur powder (Acros), ammonia solution (Sigma-Aldrich), H2PtCl6·6H2O (Alfa Aesar), and chemicals from various suppliers.

4：1). Materials included natural graphite powder (Bay carbon, SP-1), sulfur powder (Acros), ammonia solution (Sigma-Aldrich), H2PtCl6·6H2O (Alfa Aesar), and chemicals from various suppliers. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Synthesis involved modified Hummers' method for GO, annealing at 600°C with S and NH3, oxidation with HNO3, ultrasonication, autoclaving in ammonia, and Pt deposition. Photocatalytic reactions were conducted at pH 10 with light irradiation (420–800 nm or monochromatic), and H2 production was measured over time.

5：Data Analysis Methods:

XPS spectra were decomposed using Gaussian fitting, PL decay curves were fitted with bi-exponential functions, and AQY was calculated based on incident photons and evolved H2 molecules.