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Seminar - Karoliina Honkala: "Unraveling the prominent role of the Rh/ZrO2 interface in the water-gas shift reaction via a first principles microkinetic study"

Oplysninger om arrangementet

Tidspunkt

Torsdag 20. september 2018,  kl. 14:15 - 15:15

Sted

1520-616

Seminar

Speaker

Karoliina Honkala,

 

Nanoscience Center, University of Jyväskylä, Finland

Title

Unraveling the prominent role of the Rh/ZrO2 interface in the water-gas shift reaction via a first principles microkinetic study

Abstract

 

In our present study, we have used density functional theory (DFT) calculations together with microkinetic modeling to study the water-gas shift reaction (WGSR) over a zirconia supported rhodium catalyst.

The reaction energies and barriers of 13 elementary steps were determined at the DFT level for three different model systems: Rh metal, ZrO2 oxide and their interface. These energies were then used to construct a complete microkinetic model for WGSR and we solved the kinetic equations  with our own in-house microkinetic code.

Our results highlight the Rh/ZrO2-interface as the most active domain of the catalyst. The reaction is shown to proceed through the associative carboxyl pathway, with carboxyl dissociation being the rate determining step. The Rh(111) terrace is not very active towards WGS, and is mostly covered by CO at reaction conditions. The zirconia support accumulates formate, which we identify as a spectator species to the WGSR.