Oxy-methane reforming over high temperature stable NiCoMgCeO_x and NiCoMgO_x supported on zirconia-haffnia catalysts: accelerated sulfur deactivation and regeneration

Abstract

NiCoMgO_x and NiCoMgCeO_x on commercial low surface area zirconia-haffnia catalysts have unusually high thermal stability (≥2000°C) for syngas generation via the methane partial oxidation process. Herein we report the results on accelerated sulfur deactivation (0.74 mol% sulfur in feed) and corresponding regeneration (at 800°C in 1:1 O₂ + N₂ flow) over these catalysts. The NiCoMgCeO_x catalyst, due to a larger mobility of lattice oxygen, showed a considerably higher resistance to sulfur poisoning; the higher mobility of the lattice oxygen in case of the NiCoMgCeO_x catalyst may be related to the presence of CeO₂. During the deactivation process, the selectivity for H₂ was decreased to a much greater extent than that for CO. Regeneration studies showed that even after complete deactivation of the catalysts, the original activity/selectivity of both the catalysts could be completely restored after a simple regeneration process. Based on their exceptionally high thermal stability, high activity/selectivity and easily regenerability, the NiCoMgO_x and NiCoMgCeO_x catalysts appear to be very promising candidates for the CPOM process.