Enhanced Methane Conversion to Olefins and Aromatics by H‑Donor Molecules under Nonoxidative Condition

We report that methane conversion to olefins and aromatics over an iron-coated catalytic quartz reactor can be enhanced by hydrogen radicals, which are provided by the thermal decomposition of hydrogen-donor molecules, such as 1,2,3,4-tetrahydronaphthalene (THN) and benzene. For example, methane conversion increases from 19.7% to 25.5% in the presence of 1.41% THN in methane at 1323 K. The onset temperature of C2H4 formation decreases from 1143 to 1073 K by adding 7.7% C6H6 into the methane feed. Isotope experiments further indicate the involvement of H radicals in the reaction, which could activate methane homogeneously according to the reaction: ·H + CH4 → H2 + ·CH3; this occurs in addition to the heterogeneous activation of methane over iron sites.