Low-temperature catalytic oxidative coupling of methane in an electric field over a Ce–W–O catalyst system

We examined oxidative coupling of methane (OCM) over various Ce–W–O catalysts at 423 K in an electric field. Ce(2)(WO(4))(3)/CeO(2) catalyst showed high OCM activity. In a periodic operation test over Ce(2)(WO(4))(3)/CeO(2) catalyst, C(2) selectivity exceeded 60% during three redox cycles. However, Ce(2)(WO(4))(3)/CeO(2) catalyst without the electric field showed low activity, even at 1073 K: CH(4) Conv., 6.0%; C(2) Sel., 2.1%. A synergetic effect between the Ce(2)(WO(4))(3) structure and electric field created the reactive oxygen species for selective oxidation of methane. Results of XAFS, in-situ Raman and periodic operation tests demonstrated that OCM occurred as the lattice oxygen in Ce(2)(WO(4))(3) (short W–O bonds in distorted WO(4) unit) was consumed. The consumed oxygen was reproduced by a redox mechanism in the electric field.