Promotion effect of potassium carbonate on catalytic activity of Co 3 O 4 for formaldehyde removal

BACKGROUND The effect of K 2 CO 3 on modified Co 3 O 4 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), CO 2 temperature‐programmed desorption (CO 2 ‐TPD) and in situ diffuse reflectance infrared spectroscopy (DRIFTS) analyses. RESULTS The results indicated that the Co 3 O 4 sample modified by 3 wt% K 2 CO 3 was able to provide 100% conversion of HCHO to CO 2 at 100°C, while KNO 3 and KCl could barely promote the catalytic performance of Co 3 O 4 . K 2 CO 3 increased the valence state of Co and the number of oxygen vacancies on the surface of modified Co 3 O 4 , thereby enhancing the oxidation ability. The product water on the Co 3 O 4 surface could convert the carbonate to bicarbonate via hydrolysis of K 2 CO 3 , which promoted hydroxyl regeneration and accelerated intermediate species oxidation. CONCLUSION Thus, the Co 3 O 4 modified by an appropriate amount of K 2 CO 3 exhibited an excellent performance for formaldehyde oxidation removal. © 2018 Society of Chemical Industry