Structure and formation process of the water-pretreatedPt/FeOx-Al2O3 catalyst capable of CO oxidation below room temperature

Structure and formation process of water-pretreatedPt/FeOx-Al2O3 catalyst capable of CO oxidation below room temperaturehas been investigated usingPt LIIIX-ray absorption fine structure (XAFS) measurementand high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM).Before the water-pretreatment,Pt monomers and small clusters were detected while formation of Ptnanoparticles (PtNPs) having an average diameter of ≈1.3 nm and Pt-O-Fe interaction were confirmed after the pretreatment, implying that Pt monomers and small clusters aggregated at FeOx on alumina upon the pretreatment.The present results seem to indicate that the formation of Pt monomersand small clusters prior to the water-pretreatment is important for the high mobility of the Pt species and the contact formation between the Pt particles and FeOxon the resultant catalyst which is a key to the high CO oxidation activity at low temperatures.