Plasma‐catalytic one‐step steam reforming of methane to methanol: Revealing the catalytic cycle on Cu/mordenite

Direct CH4 to CH3OH conversion is a long‐standing grand challenge in catalysis. We present one‐step steam reforming of methane to methanol (OSRMtM) by combining an atmospheric pressure CH4/H2O/Ar plasma with a Cu/Mordenite (Cu/MOR) catalyst at 170°C, achieving 77% CH3OH selectivity with 3.0% CH4 conversion. Catalyst characterization and plasma diagnostics, as well as D2O and H218O‐labeled isotope tracer experiments reveal that the excellent reaction performance is attributed to Cu‐O active sites confined by MOR zeolite. During plasma‐catalytic OSRMtM, both CH4 and H2O are activated in the plasma and dissociated to produce radicals (CH3, OH, and H). These radicals drive the redox process between Cu2+ and Cu+, playing an important role in plasma‐catalytic OSRMtM. Although a gradual reduction of Cu2+ to Cu+ leads to slow deactivation, the catalytic performance can be completely recovered through simple calcination, which enables a continuous plasma‐catalytic OSRMtM process using a fluidized‐bed reactor.