Selective hydrogen oxidation in a mixture with ethane/ethene using cerium zirconium oxide

The feasibility to remove hydrogen selectively from ethane/ethene mixtures, as obtained during the catalytic dehydrogenation of ethane, is investigated. In contrast to current practice in oxidative dehydrogenation, selective oxidation of hydrogen is performed over mixed oxide solid oxygen carriers (SOCs) rather than using O2 gas. In this way a cyclic process is obtained where hydrogen is oxidized up to the point of exhaustion of the SOC. Subsequently the SOC is regenerated by oxidation with oxygen. The major obstacle to this cyclic operation is the development of a SOC material with sufficient selectivity, stability and oxygen storage capacity. We tested mixed cerium zirconium oxide coated with bismuth oxide to improve the selectivity towards oxidation of hydrogen using a combination of TPR and activity studies in a cyclically operated fixed bed. The reduction/oxidation and wetting/dewetting behavior of the SOCs is studied by XPS and discussed.