1：Experimental Design and Method Selection:

The catalyst ZnS/N–C-900 was prepared via a one-step pyrolysis method at 900°C using glucose, organic dye (K-GR), and ZnCl2 as precursors. Characterization included XRD, Raman, XPS, TEM, HRTEM, STEM-EDS, and BET analysis. Electrochemical measurements were performed using a three-electrode cell with CV, LSV, and chronoamperometry in 0.1 M KOH. DFT calculations were conducted using VASP to study reaction energies.

2：1 M KOH. DFT calculations were conducted using VASP to study reaction energies. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Samples included C-900 (pure glucose), N,S-C-900 (glucose and K-GR), and ZnS/N–C-900 (glucose, K-GR, and ZnCl2). Data were obtained from laboratory synthesis and characterization instruments.

3：2). Data were obtained from laboratory synthesis and characterization instruments. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment: XRD instrument (Bruker D8), Raman spectrometer (Renishaw), XPS spectrometer (AMICUS/ESCA 3400), TEM (JEM-2100), HRTEM (Tecnai G2 F20), STEM-EDS (LEO 1430 VP), BET analyzer (ASAP 2460), electrochemical station (CHI 760D). Materials: Glucose, K-GR organic dye, ZnCl2, de-ionized water, HCl, ethanol, Nafion, Ag/AgCl reference electrode, glassy carbon disk, graphite rod, Pt/C catalyst.

4：Experimental Procedures and Operational Workflow:

Preparation involved dissolving glucose, K-GR, and ZnCl2 in water, stirring, drying, pyrolysis at 900°C for 2 h, acid treatment, washing, and drying. Characterization steps included XRD, Raman, XPS, TEM, HRTEM, STEM-EDS, and BET analysis. Electrochemical testing involved preparing catalyst ink, drop-coating on electrode, and performing CV, LSV, and stability tests in O2-saturated KOH.

5：Data Analysis Methods:

XRD for crystalline structure, Raman for graphitization degree, XPS for chemical states, TEM for morphology, BET for surface area and porosity, Koutecky–Levich equation for electron transfer number, DFT for adsorption energies and Gibbs free energy changes.