Synthesis of novel oxygen-permeable ceramic membrane and its application in oxidation conversion of methane

A new mixed conducting oxygen-permeable membrane material, Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ, was synthesized using combined EDTA citrate complexing method. The dense membrane made of such material was successfully fabricated, and its oxygen permeation was studied. The membrane had very high oxygen semipermeability: at 850°C and under air/He with oxygen partial pressure gradient, a permeation flux of 0.744 μmol/sq sm.sec) was obtained. The intrinsic catalytic activity of the membrane for CH₄ oxidation was studied. The membrane had higher catalytic activity for oxidative conversion of methane to C₂. With the increase of methane, C₂ selectivity increased but CH₄ conversion decreased. For partial oxidation of methane to synthesis gas, CH₄ conversion was ~ 90%, CO selectivity was ~ 98%, and V(CO)/V(H₂) was ~ 2:1. Under partial oxidation of methane reaction condition, an oxygen permeation flux as high as 6.01 μmol/ (sq sm.sec) was obtained due to the increase in oxygen gradient across the membrane.