High ethylene productivity through the oxidative dehydrogenation of ethane has been achieved in a catalytic membrane reactor based on a highly solid-state oxygen permeable material (Ba0.5Sr0.5Co0.8Fe0.2O3−δ). Ethylene is selectively produced by avoiding the direct contact of molecular oxygen and hydrocarbons, thereby minimizing the oxygen concentration in the reaction side. Another key aspect in the process is the dilution of ethane in the feed to achieve high ethylene yields. There exists a specific combination of the ethane concentration and feed flow that maximizes ethylene productivity, whereas the diluting gas nature has a direct impact on the formation of higher olefins and coking issues. Indeed, the use of methane as an almost-inert dilutant allows the reduction of oligomerization and aromatization of the formed ethylene and therefore improves the reactor stability even at operating temperatures from 800 to 900 °C. This behavior is attributed to the competitive adsorption of methane and ethane/ethylene, the modification of the radical-driven homogeneous reaction, and the change of partially reducible membrane surface. The productivity values achieved at 850 °C were 383 mL min−1 cm−2 for Ar and 353 mL min−1 cm−2 for CH4, with a selectivity of 80 and 90 %, respectively.