| The formation of Mo2C and MoC supported on activated carbon was investigated in three different flowing reaction gas environments: H2, He, and CO. Additionally, benzene hydrogenation activity was studied for the catalysts reduced in each of these three different gas environments.;It was found through in-situ x-ray diffraction (XRD) that reducing in H2, ammonium heptamolybdate impregnated on activated carbon yielded 1-3 nm Mo2C particles. When the same material was calcinced in inert, 9 nm Mo2C particles were formed. If the reduction gas were CO, MoC particles having size less than 3 nm were formed. In all three reduction environments, the in-situ XRD revealed that MoO2 reduced to molybdenum carbide, without the appearance of Mo0. Data from temperature programmed reaction (TPR) spectra compared to the in-situ XRD patterns indicates that the carbon support is the source for carburization.;Only the catalyst reduced in H2 has significant activity for benzene hydrogenation. Furthermore, these Mo2C-on-carbon catalysts have only a small range of reduction temperatures, 675-825°C, for which they are active. (Abstract shortened by UMI.)... |
