Unveiling the Reaction Mechanism and the Nature of the Active Sites for Methane Conversion over Mixed-Metal Oxide Catalysts

Unveiling the Reaction Mechanism and the Nature of the Active Sites for Methane Conversion over Mixed-Metal Oxide Catalysts

Presenter

  • Felipe Polo-Garzon, Division Staff
December 7, 2018 - 1:00pm to 2:00pm

Abstract 

The speaker’s remarks will focus on two catalytic processes: (1) dry reforming of methane to produce syngas, with syngas being a starting point for the production of liquid fuels and a variety of chemicals, and (2) methane combustion for power generation and transportation.

Experiments showed that select pyrochlore materials, such as the Rh-substituted lanthanum zirconate pyrochlore (La2RhxZr2-xO7), are catalytically active for dry reforming of methane, exhibit long-term thermal stability, and resist deactivation due to coke formation. The migration of carbon atoms among gas phase species was clearly identified with the use of labeled reactants (13CH4 and 13CO2) and was related to a computationally predicted reaction pathway. The measurement of turnover frequencies suggested the participation of all surface metal atoms (Rh, Zr, La) during the catalytic cycle.

The impact of the surface reconstruction of thermally stable perovskite catalysts on methane combustion was shown by using SrTiO3 (STO) as a model perovskite. Several surface-reconstructed STO samples obtained through different synthesis and post-synthesis methods were tested for methane combustion. Activation of methane was identified as the rate-determining step by means of isotopic labeling experiments. It was found that surface segregation of Sr and creation of step surfaces can impact the rate of methane combustion by more than an order of magnitude.

Sponsoring Organization 

Chemical Sciences Division

Location

  • Chemical and Materials Sciences Building
  • Building: 4100
  • Room: C-201

Contact Information

  • Email: Zili Wu
  • Phone: 865.574.7099

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