Oxidative dehydrogenation of ethane to ethylene: A promising CeO2-ZrO2-modified NiO-Al2O3/Ni-foam catalyst

Abstract

From macro- to nano-engineering of a promising CeO2-ZrO2-doped NiO-Al2O3/Ni-foam catalyst has been demonstrated for the oxidative dehydrogenation of ethane to ethylene (ODE), through facial wet chemical etching of a Ni-foam followed post modification with CeO2 and ZrO2. The NiO-Al2O3/Ni-foam (denoted as NANF) achieved a high ethane conversion of 25.2% but with a very low ethylene selectivity of 43.1% at 450°C. ZrO2-doping of the NANF led to a remarkable improvement in the ethylene selectivity but serious deterioration of activity while the CeO2-doping showed an opposite effect. Co-doping of the NANF using optimal amount of CeO2 and ZrO2 markedly promoted not only the activity but also the selectivity to ethylene. For example, over the 1CeO2-5ZrO2-NANF (CeO2:1wt%, ZrO2:5wt%) catalyst, a high ethane conversion of 40.3% was obtained with a 60.6% ethylene selectivity for a feed gas of C2H6/O2/N2=1/1/8 at 500°C and a gas hourly space velocity of 18,000cm3g−1h−1, corresponding to a high ethylene productivity of 510gEthylenekgcat−1h−1. In nature, co-doping with CeO2 and ZrO2 synergistically tamed the NiO for selective H-abstraction of the ethane molecules other than over oxidation of them.