Controllable synthesis of Co3O4 with different morphologies and its catalytic oxidation performance of toluene
A series of Co3O4 catalysts with spherical,bow-shaped and blocky shapes were prepared by solvothermal method,and their catalytic oxidation performance to remove toluene was evaluated.These catalysts were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),H2-tem-perature programmed reduction(H2-TPR)and X-ray photoelectron spectroscopy(XPS)to discuss the relationship among their structure,surface properties and activity.The results show that the spherical Co3 O4 catalyst exhibits better catalytic activity under the test conditions of weight hourly space velocity of 40 000 mL·g-1·h-1among the three catalysts and the temperature of 90％toluene conversion(T90)is approximately 246 ℃,while T90 is 250 and 263 ℃ over the bow-shaped and block samples,respectively.Moreover,the conversion rate remains stable at 250 ℃ within 12 h for the spherical Co3O4 catalyst.It is concluded that among the three Co3 O4 catalysts with the same spinel phase,the spherical sample has the highest Co3+and the surface lattice oxygen content,and its oxidation ability is the strongest,which may be the reason for the excellent catalytic oxidation activity of toluene.
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