In Situ Time-Resolved Energy-Dispersive XAFS Study on Reduction Behavior of Pt Supported on TiO2 and Al2O3.

The dynamic reduction behavior of a highly dispersed Pt4+ to Pt0 particles on TiO2 and Al2O3 surfaces under the reductive atmosphere with an in situ time-resolved energy-dispersive X-ray absorption fine structure (DXAFS) analysis. A highly dispersed Pt4+ on TiO2 was reduced to Pt0 even at room temperature. In contrast, a highly dispersed Pt4+ on Al2O3 was gradually reduced to Pt0 even at 473 K. This result may suggest that the semiconductive behavior of TiO2 promotes the low temperature adsorption of hydrogen and supply of hydrogen atom to Pt4+ to be reduced and the activation of hydrogen on Al2O3 requires high temperature. [ABSTRACT FROM AUTHOR]