Combined with FT-IR spectroscopy (Fig. ), it is shown that there are acidic functional groups on the catalyst surface, among which the characteristic peaks of hydroxyl and carboxyl groups indicate that there are sufficient acid sites for the catalytic process. The introduction of metal Co in the Co@CS catalyst can act as a Lewis site with moderate acidity, promoting the breaking of the C-O bond. The -NH-C=O bond at 1631.001 cm -1 also confirms the presence of N in the catalyst. Subsequently, the elemental composition and valence state of the Co@CS sample were further analyzed by XPS. According to the energy spectrum (Fig. , and Co elements are present in the catalyst. For the C 1s orbital spectrum, the peak with a binding energy of 284.8 eV comes from the sp 2 C hybridization of graphene, indicating the formation of a graphitic carbon structure encapsulating metal atoms. The remaining binding energies at 285.92, 287.52, 289.37, and 292.20 eV correspond to C-N, C-O, C=O, and C(O)OH, respectively. Among them, the peak at 284.80 eV is the most important, representing the degree of graphitization of the catalyst. The peak at 285.92 eV is attributed to C-N, emphasizing the presence of N in the sample. The Co functional group characteristic peak is located in the range of 778-783 eV, corresponding to a specific form of Co 0 and Co 2+ , namely CoO and Co(OH)2, and the oscillation satellite peak of the Co element is at 785.80 eV. For the N 1s spectrum, the nitrogen species in the carbon element are mainly composed of the following: pyridinic nitrogen (398.57 eV), amino group (399.95 eV), pyrrolic N (400.87 eV), graphitic N (402.92 eV) and nitrogen oxides (406.13 eV), which is consistent with the catalyst component also using chitosan as carrier. BET characterization results (Fig. ) further illustrate that these Ndoped carbon supports show high surface area and mesoporous structure. According to the N2 adsorption-desorption isotherm, a typical IVtype isotherm with an H-3 type hysteresis loop appears, indicating that the Co@CS catalyst forms a porous structure during pyrolysis. These carbon materials are composed of nanosheets with uniform size and shape of cracks or pores, which is consistent with the SEM image observation. The specific surface area of Co@CS obtained by using the adsorption isotherm is 198.82 m 2 /g, the total pore volume is 0.215 cm 3 /g, and the average pore size is 5.576 nm. The larger specific surface area after calcination may be due to the richer pore structure produced by the partial carbonization of the material. The large surface area is conducive to providing abundant active centers for the catalytic reaction and facilitating the transport of reactants and products in the channel.