Ni-, Cu-, and Fe-loaded acidic and basic Y zeolites were synthesized, and their catalytic properties for oxidative d ehydrogenation of ethane (ODHE) to ethylene were characterized. Acidic Ni-loaded Y zeolite exhibits an ethylene productivity of up to 1.08 g(C2H4) g(cat)(-1) h(-1) with a selectivity of similar to 75%. Acidic Cu- and Fe-loaded Y zeolites have an ethylene productivity of up to 0.37 g(C2H4) g(cat)(-1) h(-1) and a selectivity of similar to 50%. For the same metal, the acidity of the zeolite favors both ODHE productivity and ethylene selectivity. Extended X-ray absorption fine structure (EXAFS) studies show that Ni, present in particles on Ni/HY during the ODHE catalytic process, contains both Ni-Ni and Ni-O bonds, and that the ratio of oxidized Ni versus metallic Ni increases with the temperature. The insights these studies provide into the ODHE reaction mechanism are discussed. (C) 2009 Elsevier Inc. All rights reserved.