Pyrolysis characteristics of Shendong coal by CH3OH-THF swelling coupled with in-situ loading of metal ions

•Coal was pretreated by CH3OH-THF swelling in-situ loading of metal ions.•The structures of coal samples were characterized by CP/MAS 13C NMR and FTIR.•The pyrolysis characteristics of coal were analyzed by TG-FTIR, Py-GC/MS, etc.•The swelling with loading of Cu2+ and Co2+ promotes the generation of benzene.•The activation energy of coal pyrolysis can be reduced by loading of metal ions.