In the search of active Ni materials for ethanol/glycerol reforming sustems we observed that specific Ni-CeO2 materials with enhanced metal-support interaction showed high activity, low selective for side reaction (methane-related) and stability. We believe that such strong interaction is the key issue but the molecular mechanism influencing catalytic properties was not fully identified. I want to ask for relevant information related to this issue.
Article High Activity of Ce1-xNixO2-y for H-2 Production through Eth...
Many thanks for the info. I read the rather good paper (as well as the very interesting following ones at RSC Advances 2012 and ChemCatChem 2013) of Jalowiecki-Duhamel and col. and consider that, as they nicely demonstrated, hydrogen can trigger a very specific Ni-Ce interaction. We are not familar with neutrons so we were not able to fully analyze such issue in our systems but tried to study the situation by in-situ XRD (and PDF-XRD) and got no "clean vision" of the structural situation. In spite of this I believe that you are right and that hydrogen is a likely part of the answer but wonder if additional info is available. I thank you again for you nice input.
Marcos, I suggest the following new paper in response to your question:
Xu, Wenqian; Liu, Zongyuan; Johnston-Peck, Aaron C.; et al. ACS Catalysis 3(5) 975-984 (2013) DOI: 10.1021/cs4000969
The deactivation process related to Ni-Ce might be worth a closer look especially relevant to the SMSI. It appears that Ni though efficient at breaking the C-C bond, with good selectivity, relies heavily on the contact with Ce for this reaction. Ce does a great job of supporting and locking Ni in place and size, but Ni migration away from Ce leads to sintering (at this point the SMSI is lost) and then C encapsulation with pure EtOH (not so obvious with MeOH but likely to be very important with glycerol). C fibers form with steam reforming, that doesnt necessarily cause rapid deactivation but is still relevant. As you know the solid solutions of NiCeOx works much better than the Ni supported catalysts and show lower levels of deactivation from the above problem.
Dear Sanjaya; thanks for the info (I need to read the paper). While the activity of the Ce-Ni interface is relatively complex to study (although the SMSI or H ideas provide routes for analysis), the stability point is, as you suggest, also of capital importance. Ni sintering is a clear issue but I do not have clear idea about the different C deposits (fibers, graphitic layers, etc..) and how they can be related to different Ni (or Ni-Ce interface) stages. Your expertise in microcoscopy may help me in understanding this. It there expecific information of such issue ?
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