| AVS 54th International Symposium | |
| Surface Science | Wednesday Sessions |
| Session SS2-WeA |
| Session: | Oxide Surface Structure I |
| Presenter: | L.R. Merte, University of Aarhus, Denmark |
| Authors: | L.R. Merte, University of Aarhus, Denmark J. Knudsen, University of Aarhus, Denmark H.H. Sørensen, University of Aarhus, Denmark R.T. Vang, University of Aarhus, Denmark M. Mavrikakis, University of Wisconsin-Madison F. Besenbacher, University of Aarhus, Denmark |
| Correspondent: | Click to Email |
The Water Gas Shift (WGS) reaction (CO + H2O -> CO2 + H2) plays an important role in the production of clean hydrogen from fossil fuels by reducing the concentration of CO in the reformed gas mixture and increasing the yield of hydrogen. The catalysts currently available necessitate a two-stage WGS process, where a high-temperature reactor is used to obtain sufficient turnover rates and a low-temperature reactor is used to push the equilibrium of the exothermic WGS reaction towards CO2 and H2 and thereby achieve higher overall conversion. Proposed systems for on-board hydrogen production to power, for example, vehicle-mounted fuel cells would require a WGS catalyst that is sufficiently active at low temperatures and is robust against degradation and poisoning under intermittent operating conditions. Development of such catalysts is therefore important if this technology is to be implemented. Iron-doped palladium based catalysts have been shown to be interesting candidates in this regard1, and our goal has been to expand our current understanding of the basic processes occurring in the Fe/Pd system, among which is the formation of iron oxide under WGS conditions. In this study we have synthesized different model systems consisting of thin iron oxide films on Pd(111) and, for comparison, Pt(111) and have shown through scanning tunnelling microscopy (STM) measurements that the morphology of these films depends strongly on the preparation conditions. Furthermore, we have studied the interaction of these films with hydrogen and the structural changes occurring upon reduction. We have also used thermal desorption spectroscopy (TDS) to examine the interaction of CO with these model systems in order to identify any chemical properties unique to the Fe/Pd system that may be relevant for the WGS reaction.
1 Zhao, S. and R. J. Gorte (2004). "The activity of Fe-Pd alloys for the water-gas shift reaction." Catalysis Letters 92(1-2): 75-80.