Stable nickel catalysts with alumina-aluminum phosphate supports for partial oxidation and carbon dioxide reforming of methane
Alumina-aluminum phosphate (AAP) materials were prepared as mesoporous catalyst supports for methane partial oxidation and dry reforming. Average pore size is substantially reduced when nickel is impregnated on the support. Large pores and adequate surface area are maintained when the nickel is co-precipitated with AAP. Impregnated nickel catalysts with γ-Al2O3 and AAP supports were tested for methane partial oxidation. Catalytic activity and selectivity was similar with both supports and performance was stable for over 100 h on stream. Under dry reforming conditions, impregnated nickel with both γ-Al2O3 and AAP supports deactivated quickly. Conversely, co-precipitated nickel catalysts showed no sign of deactivation. XRD and TPR analysis shows that stability of the co-precipitated nickel catalysts was due to strong metal–support interactions such as in the NiAl2O4 spinel structure. However lower concentrations of surface nickel and the demand for higher reduction temperatures resulted in lower conversions with the co-precipitated catalyst. Increased nickel loadings and higher reforming temperatures enhanced catalytic activity, while maintaining a stable performance for over 250 h on stream.
Graphical abstractUnder dry reforming conditions, impregnated nickel catalysts with both γ-Al2O3 and alumina-aluminum phosphate (AAP) supports deactivated quickly. Co-precipitated nickel catalysts showed no sign of deactivation. Characterization shows that stability of the co-precipitated nickel catalysts was due to strong metal–support interactions. Increased nickel loadings and higher reforming temperatures enhanced catalytic activity, while maintaining stable a performance. Figure optionsDownload full-size imageDownload as PowerPoint slide
Journal: Applied Catalysis A: General - Volume 317, Issue 2, 7 February 2007, Pages 293–298