Lignin is an important natural renewable aromatic compound,a potential substitute for fossil fuel,and a source of new energy and aromatic raw materials.The catalysts including g-C3N4 and NC-800 are prepared,and characterized by means of XRD,XPS,SEM and N2-TPD.Peroxymonosulfate(PMS)is taken as oxidant to depolymerize 4-benzyloxyphenol,an α-O-4 lignin model compound,under the catalysis of g-C3N4 and NC-800,respectively.The depolymerization process of 4-benzyloxyphenol is explored under different reaction temperature and time.It is found that the larger the specific surface area of the catalyst and the higher the content of graphite N,the higher the depolymerization rate of the model compound.The reaction mechanism is proposed for PMS oxidatively depolymerize α-O-4 lignin model compound,i.e.,reactive oxygen species attack the model compound to form various free radicals,which are further oxidized to monomer products.