Tubelike Co3O4 was successfully prepared by a facile electrospinning route combined with a subsequent calcining treatment. The as-prepared tubelike Co3O4 was exploited as peroxidase mimics and to activate peroxymonosulfate (PMS) to produce sulfate radicals. The tubelike Co3O4 exhibited intrinsic peroxidase-like activity and high ability of activating PMS to degrade 2,4-dichlorophenol compared with the powders for the high specific surface area and surface Co2+ and adsorbed oxygen contents. Furthermore, the electronic properties of Co3O4 and the catalytic mechanism on H2O2 and PMS were investigated by electron spin resonance test and density functional theory calculation. This study details the insights into Co3O4 nanomaterials for activation of peroxides and application in sustainable remediation.