BACKGROUND The effect of K2CO3 on modified Co3O4 was evaluated for the catalytic removal of formaldehyde (HCHO). The synthesized catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area, H-2 temperature-programmed reduction (H-2-TPR), CO2 temperature-programmed desorption (CO2-TPD) and in situ diffuse reflectance infrared spectroscopy (DRIFTS) analyses. RESULTS The results indicated that the Co3O4 sample modified by 3 wt% K2CO3 was able to provide 100% conversion of HCHO to CO2 at 100 degrees C, while KNO3 and KCl could barely promote the catalytic performance of Co3O4. K2CO3 increased the valence state of Co and the number of oxygen vacancies on the surface of modified Co3O4, thereby enhancing the oxidation ability. The product water on the Co3O4 surface could convert the carbonate to bicarbonate via hydrolysis of K2CO3, which promoted hydroxyl regeneration and accelerated intermediate species oxidation. CONCLUSION Thus, the Co3O4 modified by an appropriate amount of K2CO3 exhibited an excellent performance for formaldehyde oxidation removal. (c) 2018 Society of Chemical Industry