Co/CexZr1−xO2 solid-solution catalysts with cubic fluorite structure for carbon dioxide reforming of methane

The Co/CexZr1−xO2 catalysts were prepared by the impregnation method and characterized via BET, NH3-TPD, XRD, H2-TPD, H2-TPR, TEM and TG–DSC techniques. The study showed that the Co3O4 crystallites had better dispersion on the cubic fluorite CexZr1−xO2 supports compared with on the ZrO2 and CeO2, and the Co/Ce0.6Zr0.4O2 retained the cubic fluorite structure after the reaction. The Ce0.6Zr0.4O2 catalyst showed good catalytic performance, which was attributed to the alkalescence of support surface, better dispersion of active species, better textural property and reducibility. The deposition carbon over the Co/Ce0.6Zr0.4O2 catalyst mainly existed in the form of low-temperature carbon.

There were three kinds of deposition carbon on the catalysts according to the temperature of elimination carbon, named as α carbon (low temperature), β carbon (medium temperature) and γ carbon (high temperature). Only one-type carbon (β carbon) existed in the Co/ZrO2 catalyst. For Co/CeO2, there were two kinds of deposition carbon after the reaction, including β carbon and γ carbon. For Co/CexZr1−xO2, α carbon and β carbon existed in the catalysts after the reaction, indicating that carbon was easy to eliminate from the Co/CexZr1−xO2 catalysts at low and medium temperature, which was closely related with their reducibility.Figure optionsDownload as PowerPoint slideHighlights
► CexZr1−xO2 solid solution retained cubic fluorite structure of CeO2 support.
► Good dispersion of Co3O4 crystallites on cubic fluorite CexZr1−xO2 supports.
► Co/CexZr1−xO2 catalysts had better reducibility compared with ZrO2 and CeO2.
► Catalytic performance was closely related with acidity, dispersion and reducibility.
► Deposition carbon of Co/Ce0.6Zr0.4O2 mainly was low-temperature carbon.