XPS investigation of an ironrmanganesersulfated zirconia catalyst

A sample of Fe–Mn–SO42y–ZrO2has been heated at 5008C in air for 98 h. At intervals, the sample was evacuated and transferred without atmospheric exposure to an XPS chamber. As noted with Pt–SO42y–ZrO2, the O 1s peak resolved to a doublet; one of these peaks is interpreted to result by dehydration of the sulfate group. Following the 98 h air treatment, the sample was treated at 1508C at 1 atm in flowing hydrogen for a total of 78 h. The XPS spectra, obtained at intervals during the heating in hydrogen, showed that both Fe and Mn remained in an oxidized state. q1998 Elsevier Science B.V.