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

Abstract

The dynamic reduction behavior of a highly dispersed Pt 4? to Pt 0 particles on TiO 2 and Al 2 O 3 surfaces under the reductive atmosphere with an in situ timeresolved energy-dispersive X-ray absorption fine structure (DXAFS) analysis. A highly dispersed Pt 4? on TiO 2 was reduced to Pt 0 even at room temperature. In contrast, a highly dispersed Pt 4? on Al 2 O 3 was gradually reduced to Pt 0 even at 473 K. This result may suggest that the semiconductive behavior of TiO 2 promotes the low temperature adsorption of hydrogen and supply of hydrogen atom to Pt 4? to be reduced and the activation of hydrogen on Al 2 O 3 requires high temperature.

Selective hydrodeoxygenation of lignin-related 4-propylphenol into n-propylbenzene in water by Pt-Re/ZrO2 catalysts

“…A curve fitting suggested that ca. 25% fraction of Pt species was oxides and the remaining part was metal in the catalyst, using the spectra of Pt foil and PtO 2 [33]. As to Re L 3 -edge, intensity of the white line for Pt-Re/ZrO 2 corresponded to those for tetra-to hexa-valent oxides [34,35].…”

Formation mechanism of metal nanoparticles studied by XAFS spectroscopy and effective synthesis of small metal nanoparticles

“…Of these techniques, time resolved X-ray absorption fine structure (XAFS) spectroscopy is one of the most useful methods to observe metal nanoparticle formation process in situ because the chemical state and the structure of metal nanoparticles can be analyzed from the spectra. [44][45][46][47][48][49][50][51] Recently, a coupled in situ XANES and small-angle X-ray scattering (SAXS) spectroscopy was applied to elucidate the formation mechanism of gold nanoparticles from a solution of Au 3+ ions with citrate acid. 52 These studies helped describe the mechanism of nanoparticle formation, which was found to comprise different steps of particle growth via both the coalescence of nuclei and further monomer attachment.…”

In Situ Observation of Nucleation and Growth Process of Gold Nanoparticles by Quick XAFS Spectroscopy

“…Of these, quick X-ray absorption fine-structure (XAFS) spectroscopy is one of the most useful methods to observe AuNP formation process in situ because the chemical state and the structure of AuNP can be analyzed from the spectra. [15,16,17] Recently, Polte et al observed the formation process of AuNPs with citric acid by coupled in situ XANES and small-angle X-ray scattering (SAXS) spectroscopy. [18] This helped to describe the mechanism of nanoparticle formation, which was found to comprise different steps of particle growth via both the coalescence of nuclei and further monomer attachment.…”