Effect of preparation parameters on the catalytic performance of hydrothermally synthesized Co 3 O 4 in the decomposition of N 2 O

Abstract With hexadecyl trimethyl ammonium bromide (CTAB) as the template, cobaltosic oxide precursors were hydrothermally synthesized. Co 3 O 4 catalysts were then prepared by calcining the cobaltosic oxide precursors, which was further modified by impregnation with K 2 CO 3 solution and used in the decomposition of N 2 O. The catalysts were characterized by means of X-ray diffraction (XRD), nitrogen physisorption, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H 2 -TPR), and oxygen temperature-programmed desorption (O 2 -TPD); the effect of CTAB concentration, CTAB/cobalt molar ratio and urea/cobalt molar ratio on the catalytic activity of Co 3 O 4 was investigated. The results indicated that the Co 3 O 4 catalyst prepared by using 0.05 mol/L CTAB solution, with a CTAB to cobalt molar ratio of 1 and a urea to cobalt molar ratio of 4, exhibits high activity in N 2 O decomposition. The catalytic performance of Co 3 O 4 can be further enhanced by modifying with K. Over the 0.02K/Co 3 O 4 catalyst, the N 2 O conversion remains over 91% at 400°C after conducting the N 2 O decomposition reaction for 50 h in the presence of oxygen and steam.