Enhanced Activity and Stability of SrCl 2 and Na 2 WO 4 ‐MnO x /SiO 2 Dual‐Bed Catalytic System for Oxidative Coupling of Methane

ABSTRACT The commercialization of the oxidative coupling of methane (OCM) process is hindered by its low C 2 hydrocarbon yield and C 2 H 4 /C 2 H 6 product ratio. In this work, a dual‐bed catalytic system comprising a SrCl 2 additive layer packed above the classic Na 2 WO 4 ‐MnO x /SiO 2 catalyst has been proposed. The promoting effect of the introduced SrCl 2 additives is revealed. On one hand, SrCl 2 undergoes in situ oxidative dehalogenation to generate chloromethane active intermediates, which trigger chlorine radical chain transfer reactions in the OCM catalyst layer, significantly reducing the energy barriers of methane activation and ethane dehydrogenation. On the other hand, SrCl 2 , with a high melting point, prevents the metal chlorides from evaporating and covering the catalyst active sites, but still releases abundant chloromethane intermediates to participate in the OCM reaction at a moderate rate. Consequently, a more reactive and stable OCM reaction was achieved, with a C 2 yield up to 25% and a C 2 H 4 /C 2 H 6 ratio around 5 in 20 h of continuous operation. This work provides an efficient strategy for a highly active and stable OCM process.