Phase states of Li(Na,K,Rb,Cs)/W/Mn/SiO2 composite catalysts for oxidative coupling of methane

Abstract

This survey analyzes the results of studies into Li(Na,K,Rb,Cs)/W/Mn/SiO₂ composites, which are used as catalysts for oxidative coupling of methane (OCM). The focus is on phase states. Our analysis shows that the SiO₂ matrix is an active constituent of the composites and not an inert carrier of additives and the OCM heterogeneous process involves alkali-metal tungstate melts, along with polycrystalline manganese oxides. The effects of the cation ratio and synthetic routes on the phase composition of Li(Na,K,Rb,Cs)/W/Mn/SiO₂ are assessed.