BACKGROUNDAtrazine is present in aquatic systems as a pesticide, and poses a serious threat to ecosystems and human health. The advanced oxidation technology based on persulfate is considered a promising approach for removing trace pesticides from water. The synthesis of a persulfate activator for the rapid and efficient degradation of atrazine was studied.RESULTSA novel rod‐like sulfur‐doped Co3O4 (S‐Co3O4) was prepared via the hard template method and used as a persulfate activator to degrade atrazine. The removal efficiency of atrazine (10 mM) could be up to 100% in the presence of peroxymonosulfate (1 mM) activated by S‐Co3O4 (50 mg L−1) within 7 min.CONCLUSIONThe nanorod structure of S‐Co3O4 is conducive to mass transfer and increases the probability of reaction between substances, and sulfur doping increases the interfacial charge transfer capability. The mechanism of atrazine degradation was mainly attributed to the combined effects of •OH and SO4•−, with the effect of SO4•− being more important. The main degradation pathways of atrazine are dichlorination, hydroxylation and dealkylation, corresponding to the cleavage of Cl1‐C9, N5‐C10 and N6‐C11, respectively. © 2024 Society of Chemical Industry (SCI).