1：Experimental Design and Method Selection:

A selenide reaction packaging strategy was used to synthesize CoSe2 nanoparticles trapped in N-doped carbon polyhedra (NC) using ZIF67 as a precursor. This involved pyrolysis and selenization reactions to create a hybrid material with enhanced catalytic properties.

2：Sample Selection and Data Sources:

ZIF67 was synthesized as the precursor. Samples were prepared at different temperatures (700, 800, 900 °C for pyrolysis and 350, 400, 450 °C for selenization) to optimize the catalyst.

3：List of Experimental Equipment and Materials:

Equipment included crucibles, furnaces for heating under inert gas, centrifuges, vacuum ovens, and electrochemical cells. Materials included Co(NO3)2, 2-methylimidazole, methanol, Se powder, H2SO4, and KOH.

4：Experimental Procedures and Operational Workflow:

ZIF67 was synthesized by mixing Co(NO3)2 and 2-methylimidazole in methanol, followed by centrifugation and drying. Co-NC hybrids were prepared by pyrolysis of ZIF67 under Ar, acid leaching with H2SO4, and washing. CoSe2-NC hybrids were obtained by mixing Co-NC with Se powder and heating under Ar for selenization. Electrochemical performance was evaluated using linear sweep voltammetry, Tafel plots, and stability tests in acidic and alkaline electrolytes.

5：Data Analysis Methods:

XRD, XPS, SEM, TEM, STEM, EDX, nitrogen adsorption/desorption isotherms, BET surface area, BJH pore size distribution, Raman spectroscopy, TGA, and electrochemical measurements (LSV, CV, EIS) were used for characterization and analysis.