▎ 摘　　要

NOVELTY - Monoatomic catalyst has M-N-C structure. USE - Monoatomic catalyst used for catalytically degrading polychlorinated biphenyl (claimed). ADVANTAGE - The method is simple and practical, suitable for synthesizing single atoms on various supports, and the obtained single-atom site catalyst has fully exposed single-atom sites, which effectively improves the utilization rate of single atoms. The Fe-N-C single-atom catalyst shows excellent performance in the thermal catalytic degradation of decachlorobiphenyl. DETAILED DESCRIPTION - Monoatomic catalyst has M-N-C structure, where M is Fe, Co, Mn, Ni, Pt, Pd, M exists in the form of a single atomic site, N-C represents nitrogen-doped carbon carrier. The carbon carrier is semi-hollow carbon spheres, carbon nanotubes, and graphene, where the loading of M is 0.1-10 wt.% based on the total weight of the catalyst. INDEPENDENT CLAIMS are included for: (1) A method for preparing M-N-C monatomic catalyst, which involves mixing the solution containing M metal salt with a carbon-based carrier, and heating and drying to obtain a catalyst precursor. The precursor and the nitrogen-releasing small molecular compound are respectively placed in a device with the same reaction space for calcination to obtain the catalyst, where the M metal salt is acetylacetone salt of M metal, and the solvent of the solution is 1-6C alcohol solvent. The carbon-based carrier is graphene, carbon nano tube and carbon black carrier. The heating and drying aim to remove the solvent. The nitrogen-releasing small molecule compound is dicyandiamide, urea or melamine. The calcination is carried out at 400-800degrees Celsius, the calcination atmosphere is nitrogen or argon, and the calcination time is 4-8 hours. (2) A method for catalytically degrading polychlorinated biphenyl, which is a gas-solid reaction, that includes taking M-N-C as a catalyst, and catalytically degrades polychlorinated biphenyl in the atmosphere of nitrogen and water vapor, where the catalyst is a single-atom catalyst of Fe-supported semi-hollow carbon spheres, and the polychlorinated biphenyl is decachloro biphenyl.