In Situ Industrial Bimetallic Catalyst Characterization using Scanning Transmission Electron Microscopy and X‐ray Absorption Spectroscopy at One Atmosphere and Elevated Temperature

• Published in: Chemphyschem 2017-08, Vol.18 (16), p.2151-2156
• Main Authors: Prestat, Eric, Kulzick, Matthew A., Dietrich, Paul J., Smith, Mr. Matthew, Tien, Mr. Eu‐Pin, Burke, M. Grace, Haigh, Sarah J., Zaluzec, Nestor J.
• Format: Article
• Language: English
• Subjects: Absorption spectroscopy; Bimetals; Catalysts; Chemical synthesis; Chemistry; Communication; Communications; Electron energy; Electron energy loss spectroscopy; electron microscopy; Energy dispersive X ray spectroscopy; High temperature; nanoparticles; Physics; Scanning electron microscopy; Scanning transmission electron microscopy; Spectrum analysis; supported catalysts; Titanium oxides; Transmission electron microscopy; X-ray absorption spectroscopy; X-rays
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.201700425

We have developed a new experimental platform for in situ scanning transmission electron microscope (STEM) energy dispersive X‐ray spectroscopy (EDS) which allows real time, nanoscale, elemental and structural changes to be studied at elevated temperature (up to 1000 °C) and pressure (up to 1 atm). Here we demonstrate the first application of this approach to understand complex structural changes occurring during reduction of a bimetallic catalyst, PdCu supported on TiO2, synthesized by wet impregnation. We reveal a heterogeneous evolution of nanoparticle size, distribution, and composition with large differences in reduction behavior for the two metals. We show that the data obtained is complementary to in situ STEM electron energy loss spectroscopy (EELS) and when combined with in situ X‐ray absorption spectroscopy (XAS) allows correlation of bulk chemical state with nanoscale changes in elemental distribution during reduction, facilitating new understanding of the catalytic behavior for this important class of materials. In situ elemental mapping: A new experimental platform for in situ scanning transmission electron microscope energy dispersive X‐ray spectroscopy is presented, which allows real time, nanoscale, elemental and structural changes to be studied at elevated temperature (up to 1000 °C) and pressure (up to 1 atm).