(650a) Towards the Design of Sulfur-Tolerant CO2-Reforming Catalysts
To date, we have found that Ce-Zr supports at the 1:1 or higher elemental ratio are superior to the Ce-La supports at similar elemental ratios. The latter are relatively inactive. We have also found that coking rates in the absence of water are strongly dependent upon stoichiometric equivalence between CO2 and CH4. Structurally, both the Ce-Zr and Ce-La families of supports show no post-mortem evidence of separate TM (Ni, Mn, Fe) or TM oxide phases, at least for TM:REO ratios kept below thresholds determined in past work on tar reforming. Characterizations of the used catalysts have included XANES, XAFS, Raman, XRD and chemisorption techniques.
Extended coking rate measurements by DSC-TGA show that for the TM-doped REO catalysts a coking plateau is attained, while for simpler Co- and Ni-supported Al2O3Â catalysts the coking rates are nonzero and almost constant. This suggests that regardless of their short-term performance, the latter family of catalysts supported on Al2O3 will ultimately deactivate more rapidly.
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- M. Krcha, K. Dooley, and M. Janik, âAlkane Reforming on Partially Sulfided CeO2 (1 1 1) Surfaces,â J. Catal., 330, 167-176 (2015)