Upon using a reactant/oxygen mixture as co-feed in partial oxidation, adsorbed surface molecular oxygen species can cause low selectivity. We propose a concept different from the conventional co-feed partial oxidation process in packed-bed reactors. In this new configuration, the activation of oxygen is separated from the catalytic oxidation by using an oxygen-permeable membrane to suppress the formation of nonselective surface molecular oxygen species. A continuous flux of lattice oxygen through the membrane allows highly selective partial oxidation. In the oxidation of ammonia to NO, the NO selectivity was improved from 77 to 95 % if a La0.6Sr0.4Co0.2Fe0.8O3–δ oxygen-permeable catalytically active membrane was used at 850 °C instead of a co-feed fixed bed reactor.