Atomic-scale studies of catalysis
by spinel oxides

Subproject P04

The spinel class of metal oxides hosts diverse materials, some of which make excellent catalysts. Fe3O4 is already the industrial catalyst for the high-temperature water-gas shift reaction (CO+H2O -> H2+CO2), but research is needed to identify the optimal replacement for the toxic Cr promoter/stabilizer. Ternary MeFe2O4 compounds (Me=Fe, Ni, Co, Mn) are active and stable for the electrochemical oxygen evolution reaction (OER). However, the structure of the active catalyst and the reaction mechanisms are unknown. While these reactions appear different, both clearly benefit from a combination of multivalent cations in the surface layers.

In this project, we will seek to learn why, using a combination of atomic-scale imaging, a host of spectroscopies, and theory. We will dope the Fe3O4(001) surface with 3d transition metals and investigate how the adsorption energies, XPS binding energies, and IRAS frequencies of H2O, CO, CO2, O2, and H2 change with sample composition all the way from isolated dopants to ternary thin films. We will use the data obtained in tightly-controlled UHV experiments to:

i) Interpret the reactivity of our model catalysts under realistic HTWGS and OER conditions.

ii) Provide the benchmark data for experiments on nominally similar powder catalysts (P10 Föttinger).

iii) Support the development of theoretical modeling (P07 Franchini).

A joint postdoc (P04-P11) will facilitate the new collaboration with P11 Backus.

Gareth S. Parkinson
PI

Expertise

The group focuses on understanding mechanisms of catalytic reactions using a combination of experimental surface science and theoretical calculations. We have access to a total of seven ultrahigh-vacuum (UHV) chambers, which allows us to conduct the following experiments:
  • Scanning Tunneling Microscopy (STM) (in UHV 4K – 300 K, electrochemical STM)
  • Atomic Force Microscopy (AFM): UHV-based (q+ sensor) and in the ambient (cantilever-based)
  • Low-Energy Electron Diffraction (LEED)
  • Reflection High Energy Diffraction (RHEED)
  • X-ray Photoelectron Spectroscopy (XPS)
  • Ultraviolet Photoelectron Spectroscopy (UPS)
  • Auger Electron Spectroscopy (AES)
  • Low-energy He+ ion scattering (LEIS)
  • Thermal Programmed Desorption Spectroscopy (TPD)
Of particular use for TACO is our surface reactivity chamber, which is specifically designed to study single-crystal metal-oxide samples. Reactants are delivered to the sample by molecular beams, and products detected by a mass spectrometer. In addition to TPD, XPS, UPS, and LEIS, we will soon be able to perform infrared absorption spectroscopy (IRAS) experiments on these samples using an optimized beam geometry.

Team

Gareth S. Parkinson
PI

Jiří Pavelec
co-PI

Chunlei Wang
PostDoc

David Rath
PhD Student

Associates

Moritz Eder
PostDoc

Publications

Show all

43 entries « 5 of 5 »

2016

Methane dry reforming over ceria-zirconia supported Ni catalysts

Wolfbeisser, Astrid; Sophiphun, Onsulang; Bernardi, Johannes; Wittayakun, Jatuporn; Föttinger, Karin; Rupprechter, Günther

Methane dry reforming over ceria-zirconia supported Ni catalysts

Journal ArticleOpen Access

In: Catalysis Today, vol. 277, pp. 234–245, 2016.

Abstract | Links | BibTeX | Tags: P08, P10, pre-TACO

High-Throughput Computation of Thermal Conductivity of High-Temperature Solid Phases: The Case of Oxide and Fluoride Perovskites

van Roekeghem, Ambroise; Carrete, Jesús; Oses, Corey; Curtarolo, Stefano; Mingo, Natalio

High-Throughput Computation of Thermal Conductivity of High-Temperature Solid Phases: The Case of Oxide and Fluoride Perovskites

Journal ArticleOpen Access

In: Physical Review X, vol. 6, no. 4, pp. 041061, 2016.

Abstract | Links | BibTeX | Tags: P09, pre-TACO

2014

In Situ Spectroscopy of Complex Surface Reactions on Supported Pd–Zn, Pd–Ga, and Pd(Pt)–Cu Nanoparticles

Föttinger, Karin; Rupprechter, Günther

In Situ Spectroscopy of Complex Surface Reactions on Supported Pd–Zn, Pd–Ga, and Pd(Pt)–Cu Nanoparticles

Journal Article

In: Accounts of Chemical Research, vol. 47, no. 10, pp. 3071–3079, 2014.

Abstract | Links | BibTeX | Tags: P08, P10, pre-TACO

43 entries « 5 of 5 »