High-performance Ni-foam-structured Nb2O5-NiO nanocomposite catalyst for oxidative dehydrogenation of shale gas ethane to ethylene: Effects of Nb2O5 loading and calcination temperature

Large-scale shale gas exploitation greatly enriches ethane resources, making the coddative dehydrogenation of ethane (ODE) to ethylene quite fascinating, but the qualified catalyst presents a grand challenge. A series of Ni-foam-structured MOx-NiO (M = Li, Mg, Ga, Ce, Zr, Mo, W, Nb) composite oxide catalysts (denoted as MOx-NiO/ Ni-foarn) have been developed for the oxidative dehydrogenation of ethane to ethylene (ODE). The catalysts were obtained by hydrothermal growth of NiC2O4 onto a Ni-foam (110 PPI) and subsequent impregnation with an M-containing salt aqueous solution and calcination treatment. Among them, the Nb2O5-NiO/Ni-foam showed superior catalytic ODE performance over the others. Both Nb2O5 loading and calcination temperature showed remarkable impact on the catalytic performance. The modification with suitable amount of Nb2O5 was responsible for the significant elimination of non-selective oxygen species thereby leading to remarkable improvement of the ethylene selectivity. The activity and selectivity of the Nb2O5-NiO/Ni-foam catalysts are also sensitive to the calcination temperature that can modulate the desorption properties of their lattice oxygen species to a great extent. The most promising Nb2O5-NiO/Ni-foam catalyst is the one modified with 5 wt% Nb2O5 and calcined at 450 degrees C, being capable of converting 60% ethane with a 68% ethylene selectivity for a feed of C2H6/O-2/N-2 = 1/1/8at 410 degrees C and GHSV of 9000 cm(3) g(-1) h(-1) (corresponding to a high ethylene productivity of 0.423 g(c2H4) g(cat)(-1) h(-1)).