High-Performance Ni-Foam-Structured Nb2O5-NiO Nanocomposite Catalysts for Oxidative Dehydrogenation of Ethane to Ethylene

We report a promising Nb₂O₅-NiO/Ni-foam catalyst for the ODE reaction, which achieves an ethylene productivity of 0.43 g_Ethylene g_cat^-1 h^-1 at 60% ethane conversion with 68% ethylene selectivity for a feed of C₂H₆/O₂/N₂=1/1/8 at 410 ^oC and a high GHSV of 9000 cm³ g^-1 h^-1, and showed good stability due to high resistance to sintering. Such catalyst engineered from nano- to macro-scale is only obtainable by endogenous growth of NiC₂O₄·2H₂O onto Ni-foam followed by (niobium ammonium oxalate)-modification and subsequent pyrolysis treatment. In this case, the Nb₂O₅ lumps were formed to have the NiC₂O₄-derived NiO nanorods partially covered up, and therefore induced helpful weak interaction between Nb₂O₅ and NiO while leading to a remarkable reduction of the nonselective O₂^‑ species but almost not touching the selective O^‑ species. External and partial coverage of the NiC₂O₄-derived NiO nanorods with Nb₂O₅ lumps, coupled with foam-structure enhanced heat transfer, is paramount for high-efficiency ethylene production.