Effect of preparation parameters on the catalytic performance of hydrothermally synthesized Co3O4 in the decomposition of N2O

Abstract

With hexadecyl trimethyl ammonium bromide (CTAB) as the template, cobaltosic oxide precursors were hydrothermally synthesized. Co3O4 catalysts were then prepared by calcining the cobaltosic oxide precursors, which was further modified by impregnation with K2CO3 solution and used in the decomposition of N2O. 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 (H2-TPR), and oxygen temperature-programmed desorption (O2-TPD); the effect of CTAB concentration, CTAB/cobalt molar ratio and urea/cobalt molar ratio on the catalytic activity of Co3O4 was investigated. The results indicated that the Co3O4 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 N2O decomposition. The catalytic performance of Co3O4 can be further enhanced by modifying with K. Over the 0.02K/Co3O4 catalyst, the N2O conversion remains over 91% at 400°C after conducting the N2O decomposition reaction for 50 h in the presence of oxygen and steam.