Coke Suppression by Holmium Promoter in Dry Reforming of Methane

摘要

The present research mainly focused on the development of highly coke resistant catalysts. In this context, Ni/ZrO2 novel catalysts with holmium (Ho) promoter were prepared using the polyol method and investigated, for CH4-CO2 reforming, at atmospheric pressure in the temperature range of 500-700 degrees C. For each catalyst, the Ni loading was fixed at 5 wt.%, while Ho loading was varied from 0.0-1.5 wt.%. Various techniques such as BET, H-2-TPR, CO2-TPD, XRD, TGA and FESEM were used to characterize the prepared catalysts. The results demonstrated that the addition of Ho in Ni/ZrO2 catalyst had a notable effect on carbon suppression. Moreover, CO2-TPD results revealed that the incorporation of Ho in Ni/ZrO2 catalyst fairly enhanced its Lewis basicity. These improvements in basicity favored the chemisorption and activation of CO2 over the catalyst surface which in turn minimized coke deposition. Carbon deposition on the 1.5 wt.% Ho promoted catalyst (Ni-1.5Ho-Zr) was reduced about 92.7% compared to the un-promoted catalyst.