The　direct　partial　oxidation　of　CH4　to　dimethyl　ether　(DME)　on　a　Pt/Y2O3　catalyst　was　studied　using　a　mixture　of　NO　and　O-2　as　the　oxidant.　The　reaction　was　carried　out　in　a　fixed　bed　reactor　at　0.1　MPa　and　275-400　degrees　C　using　20%　CH4,　1%　NO,　and　1%　O-2　in　inert　gas.　No　methanol　was　detected　in　the　effluent　and　a　contact　time　study　demonstrated　that　DME　was　a　primary　product.　The　DME　productivities　were　comparable　to　the　oxygenate　(methanol,　formaldehyde)　productivities　obtained　with　stronger　oxidants　such　as　N2O,　H2O2,　and　O-3.　The　presence　of　Pt　and　the　NO　+　O-2　gas　mixture　was　necessary　for　DME　formation;　without　NO　only　CO2　was　produced.　During　the　methane　partial　oxidation　reaction　NO　and　NO2　were　not　reduced　to　N-2,　indicating　that　they　worked　as　a　shuttle　to　transfer　oxygen　from　O-2　to　CH4.　In　situ　Fourier　transform　infrared　showed　the　formation　of　a　bridged　nitrate　species　on　the　Pt/Y2O3　catalyst　which　was　associated　with　the　reaction　of　CH4.　A　comprehensive　study　of　this　bridged　nitrate　species　indicated　they　were　formed　on　yttria　sites　close　to　Pt　and　were　likely　responsible　for　the　formation　of　DME.　The　characterization　of　catalysts　using　X-ray　diffraction　showed　that　the　Pt　was　highly　dispersed　and　CO　uptake　measurements　indicated　a　particle　size　of　similar　to　3　nm.　Analysis　by　X-ray　absorption　fine　structure　measurements　showed　the　presence　of　Pt　oxide　with　Pt-O　and　Pt-Pt　bonds.　(C)　2020　Elsevier　Inc.　All　rights　reserved.