Oxidative Dehydrogenation of Ethane over Boron-Containing Chabazite

We report that boron-containing zeolite chabazite (B-CHA) catalyzes the oxidative dehydrogenation of ethane (ODHE) with high selectivity (>70%) and excellent stability in the temperature range of 500-600 °C. ODHE rates, in fact, increase over time on stream. Ethane consumption rate has an apparent activation energy of 126kJmol-1, with Langmuirian dependence on the oxygen partial pressure and first-order dependence on the ethane partial pressure. Investigation of the catalyst before and after reaction by one-dimensional 11B magic angle spinning (1D 11B MAS) nuclear magnetic resonance (NMR), two-dimensional 11B multiple quantum MAS (2D 11B MQMAS) NMR spectroscopy, and Fourier transform infrared (FTIR) spectroscopy identifies the B-OH group in defect trigonal boron (B(OSi)(OH)2) as the species initiating the ODHE reaction. This result could open a pathway to develop suitable catalysts for industrial ethylene production with lower greenhouse gas emissions than current non-oxidative dehydrogenation routes.