The manipulation of adsorption properties of catalysts and membranes in H2/CO mixtures has been targeted many researchers, and has relevance to natural gas conversion in general and hydrogen technology in particular. We recently discovered that the inhibi tion of hydrogen transport through PdAg membranes by carbon monoxide could be significantly reduced by heat treatment of the membrane in air. Analysis by fitting of experimental data and modelling showed that changes in CO an H2 heats of adsorption could be part of the picture. Surface spectroscopy indicated that surface segregation phenomena could be involved, but more detailed investigations are needed to explain the effects.
The overall objective of this research is therefore to understand how the re sponse of Pd alloy surfaces to carbon monoxide and carbon dioxide the in presence of hydrogen is affected by the structure and composition of the surface, and to eventually apply this knowledge into improved membranes, membrane reactors and catalysts. Thi s calls for an approach where advanced characterization techniques are used in conjunction with detailed calculations/modelling.
The project partners are the NTNU Departments of Chemical Engineering and Physics and SINTEF Materials and Chemistry, with th e University of Wisconsin-Madison as an international partner. The research will be conducted through one postdoctoral fellowship and one PhD project. Experimental investigations of binding energies, adsorption sites and surface species will be targeted t hrough a wide range of techniques available on campus. Both model systems (single crystals) and membrane samples surfaces (sputtered Pd alloy thin films) will be studied and compared. High intensity, X-ray range, tuneable synchrotron radiation will be uti lized for high resolution, surface sensitive photoelectron spectroscopy and diffraction experiments. Density functional theory calculations and microkinetic modelling will be performed to interpret the data.