Methane combustion activity of Pd–PdOx–Pt/Al2O3 catalyst: The role of platinum promoter

The effect of Pt promoter on Pd–PdOx/Al2O3 catalyst was investigated to improve understanding of the role of promoter formation of the active phase of Pd–PdOx–Pt/Al2O3 methane combustion catalysts. The influence of Pt addition on the composition of the active catalyst surface was characterized by NH3 temperature programmed desorption procedure. Addition of promoter improved the low temperature CH4 combustion activity of the aged catalyst, though it caused a decrease in activity of the fresh catalyst. The changes in activity were related to changes in the ratio of the metal to metal oxide phases in the surface composition. Pt tends to create metal sites, whereas Pd prefers the formation of metal oxide sites. Catalyst preparation parameters affect the Pd/PdOx ratio of the non-promoted monometallic Pd catalyst, and the ratio needs to be known so that the proper amount of Pt promoter can be added.

Figure optionsDownload high-quality image (100 K)Download as PowerPoint slideHighlights
► Addition of Pt improves aging durability of the Pd–PdOx catalyst.
► Active phase of the catalysts consists of metallic (M) and metal oxide (MOx) sites.
► The M/MOx ratio corresponds to CH4 combustion activity.
► The function of Pt promoter is to increase number of metallic sites on the active phase.