Direct non-oxidative methane conversion (DNMC) over iron/silica (Fe/SiO
2) catalysts is a promising solution for developing fuels and chemicals from methane. The endothermic DNMC reaction requires high energy input to reach temperatures required for desirable methane conversion. Co-feeding oxygen (O
2) over quartz-supported Fe-species (Fe/SiO
2(Q), âQâ denotes quartz) catalysts resulted in greater than 100% increase methane conversion and 50% increase in product yield while supplying heat for DNMC from energy released during CO and CO
2 formation. Fe/SiO
2(Q) was prepared via flame-fusion, maintaining the quartz SiO
2 crystalline phase, unlike melt-fusing methods resulting in a phase transformation to cristobalite. In DNMC, the catalyst had only a brief induction period and good stability. At low concentrations, the O
2 co-feed increased methane conversion and hydrocarbon yield, suggesting that oxidative coupling of methane promotes C
2 and aromatics formation. Analyses of spent Fe/SiO
2(Q) catalysts indicated that the O
2 co-feed alters the coking species that actively participate in DNMC.
