Ge-modified Pt/SiO2 catalysts used in preferential CO oxidation (CO-PROX)

A bimetallic PtGe catalyst was prepared by a controlled surface reaction and studied for the PROX reaction. The good activity of the bimetallic catalyst can be assigned to the presence of a “noble metal-oxidized metal promoter” ensemble site in close contact, the noble metal (Pt) being the CO adsorption site and the oxidized metal promoter (Ge) the O2 adsorption site. The stability of the PtGe clusters is confirmed by the EXAFS spectra and activity measurements in the preferential oxidation reaction that show similar values for samples subjected to different oxidation–reduction cycles.

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► PtGe catalyst presents a "noble metal-oxidized metal promoter" ensemble site.
► Pt is the CO adsorption site and the GeOx the O2 adsorption site.
► The stability of the PtGe clusters is confirmed by EXAFS and activity measurements.
► PtGe systems, unlike PtSn systems, do not show alloy formation.
► Electronic effect with charge transfer from Pt to Ge is evidenced by XANES spectra.