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[Display omitted] • The chelation of –NH 2 to metal ions enhances the formation of small Co 3 O 4 particles. • N doping regulates the valence states of Co and oxygen vacancies. • The presence of Brønsted and Lewis acid sites promotes the adsorption of C 8 H 8. • The oxidation reactions are mainly dominated by the Mars-van Krevelen mechanism. • Good C 8 H 8 oxidation activity, thermal stability and water-resistance are achieved over CS/Co 3 O 4 -W. In this study, a Co 3 O 4 catalyst is synthesised using the chitosan-assisted sol–gel method, which simultaneously regulates the grain size, Co valence and surface acidity of the catalyst through a chitosan functional group. The complexation of the free –NH 2 complex inhibits particle agglomeration; thus, the average particle size of the catalyst decreases from 82 to 31 nm. Concurrently, Raman spectroscopy, hydrogen temperature-programmed reduction, electron paramagnetic resonance spectroscopy and X-ray photoelectron spectroscopy experiments demonstrate that doping with chitosan N sources effectively modulates Co2+ to promote the formation of oxygen vacancies. In addition, water washing after catalyst preparation can considerably improve the low-temperature (below 250 °C) activity of the catalyst and eliminate the side effects of alkali metal on catalyst activity. Moreover, the presence of Brønsted and Lewis acid sites promotes the adsorption of C 8 H 8. Consequently, CS/Co 3 O 4 -W presents the highest catalytic oxidation activity for C 8 H 8 at low temperatures (R 250 °C = 8.33 μmol g−1 s−1, WHSV = 120,000 mL hr−1∙g−1). In situ DRIFTS and 18O 2 isotope experiments demonstrate that the oxidation of the C 8 H 8 reaction is primarily dominated by the Mars–van Krevelen mechanism. Furthermore, CS/Co 3 O 4 -W exhibits superior water resistance (1- and 2- vol% H 2 O), which has the potential to be implemented in industrial applications. [ABSTRACT FROM AUTHOR]