| 초록 |
V2O5 catalysts ranging from 5 to 20 wt% supported on Ce-Mg-O oxides with Ce/Mg mol ratio of 2/8 are prepared by the co-precipitation method. The influence of the oxidative agent H2O2 and calcination temperature on the catalyst propertiesare studied. The catalysts are characterized by N2 adsorption, XRD, FT-IR and SEM. XRD pattern shows that a large amount of MgO phase exists simultaneously with CeO2 phase in 2Ce-8Mg-O oxide prepared with H2O2. This opinion is confirmed by FT-IR spectra, two characteristic peaks of the adsorbed CO2 and Mg-O bond are observed. The difference of morphology is also observed in SEM. Vanadium oxide below 8 wt% is finely dispersed on the support surface while the non-active Mg3(VO4)2 phase is formed if vanadia loadings above 8 wt%. Among the catalysts studied here, 8V2O5/2Ce-8Mg catalyst outperforms all others in the dehydrogenation of ethylbenzene. For the vanadia loadings upto 8 wt% the ethylbenzene conversion and the styrene selectivity increase, whereas, above 8 wt% then the ethylbenzene conversion decreased progressively while the styrene selectivity is still maintained. |
