A modified porous ceramic microfiltration membrane has been used as an oxygen distributor to a fixed bed catalytic reactor for methane oxidative coupling. For the first time, in this work the pore structure along the membrane has been altered, in order to attain a controlled, non-uniform pattern of oxygen permeation, which is shown to have significant advantages for the reaction investigated. The different permeation arrangements employed have been characterized, and compared in terms of the conversion and selectivity achieved.