CuO particles were attempted to fill in the channel of multi-walled carbon nanotubes(MWCNTs)as novel catalytic materials CuO@MWCNTs used for ozonation of humic acids(HA)in aqueous solution.Catalyst samples were characterized by transmission electron microscopy(TEM),X-ray diffraction(XRD),thermogravimetric analysis(TG)and X-ray photoelectron spectroscopy(XPS).The removal efficiency of HA was promoted in the presence of CuO@MWCNTs compared with that of Al2 O3-supported CuO catalyst(CuO/Al2O3)and CuO-coating MWCNTs catalyst(CuO/MWCNTs).The strong synergetic effect in the confinement environment on CuO nanoparticles can attribute to the locally higher pressure due to the lower potential energy of reactants in the channels.Strong interaction happened between the catalyst and reactants,which promoted the decomposition of ozone and the generation of OH.The results of experimental and theoretical investigation confirmed that CuO@MWCNTs promotes the initiation and generation of OH,hence accelerating the degradation of organic pollutants.