Partial oxidation of CH 4 using molecular oxygen has been carried out over various commercial silicas and alumina doped silica catalysts using a flow reactor system. Partial oxidation products such as C 2 H 6 , C 2 H 4 , HCHO, CH 3 OH, and CO were formed over these catalysts as well as over a quartz reactor only. The presence of Al ions in silica remarkably enhanced the formation of C 2 H 6 , H 2 , HCHO, and CO even at low O 2 concentrations. States of Al ions in silica were studied using MAS NMR of 27 Al. The results indicated that tetrahedrally coordinated Al(4) ions seem to be present and be isolated in silica. The mechanism of CH 4 oxidation is proposed under the heterogeneous participation of O 2 activated on such sites.