Mesoporous silica supported cobalt oxide catalysts for catalytic removal of benzene

Abstract

Two types of mesoporous silica SBA-15 with different pore diameter were synthesized with an ageing temperature of 373 K and an ageing temperature of 308 K, respectively; in addition, mesoporous silica with amorphous structure was synthesized by adding organosiloxane as part of the silica source during the synthesis procedure. Mesoporous silica and conventional alumina supported cobalt oxide catalysts were prepared by incipient wetness impregnation method. These materials were characterized by FT-IR, nitrogen adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Temperature programmed reduction (TPR) techniques, and the activity of the supported cobalt oxide catalysts for deep oxidation of benzene were evaluated in a fixed-bed reactor. It seems that the pore diameter of the silica increase with the elevation of the ageing temperature. Mesoporous silica supported cobalt oxide catalysts are more active than conventional alumina supported ones. Cobalt oxide can be relatively better dispersed on the surface of mesoporous silica which has larger pore diameter and surface areas. Meanwhile, more silanol groups exist on the surface of amorphous silica, which could induce a strong interaction with the supported cobalt oxide species, leading to poor activity for benzene oxidation.