Conditioning of Rh/α-Al2O3 catalysts for H2 production via CH4 partial oxidation at high space velocity

摘要: Abstract Experimental evidence and literature indications suggest that the process of methane partial oxidation over Rh catalysts is structure sensitive. Crystal phases cluster size are thus expected to affect final catalytic performance. In this work, it observed outstanding performances obtained when as-prepared conditioned through repeated runs at increasing temperature O2/CH4 = 0.56. Catalysts slowly activate, CH4 conversion synthesis gas selectivity progressively grow with time on stream. On basis TPO decomposition measurements, phenomenon herein explained as result a surface reconstruction driven by exposition reaction high temperature; thought such tends eliminate defect sites disfavors C-deposition reactions (extremely fast steps kinks). Conditioning O2-enriched feed streams makes conditioning faster, since accumulation C-species suppressed; however, catalyst eventually less active than standard mixtures. As an alternative, carbon can be suppressed proceeds faster if directly exposed for several hours.