Ethane ammoxidation into acetonitrile was successfully catalyzed between 380 and 450 degrees C over Co/BEA solids issued from solid-state ion exchange with different metal loads. During the preparation, in the presence of NH4+-Beta zeolite (Si/Al = 12.5), CoCl2 precursor decomposes under helium stream without evaporation, leading to the stabilization of bare Co2+ at the exchange cationic sites as revealed by spectroscopic tools. However, at 4.13 and 5.63 wt.% of Co (Co/Al molar ratio equal to 0.75 and 1, respectively), the corresponding solids stabilized, besides bare beta-type Co2+ ions, Co oxo [Co(III)O](+) species, revealed by H-2-TPR. These species exhibit highest catalytic activity on the basis of TOF calculation and play a key role in ethane ammoxidation into acetonitrile at low temperature (380 degrees C). Nevertheless, the excess of cobalt is transformed into Co3O4 oxide (as revealed by XRD and TPR experiments) which catalyzes the hydrocarbons combustion into CO2.