Lower olefins (C2 to C4) are extensively used in the chemical industry as key building blocks. Traditionally, lower olefins have been produced by thermal or catalytic cracking of naphtha or vacuum gas oil or from dehydrogenation of alkanes.However, environmental and economic factors are currently spurring exploration of alternative routes for their production. Syngas, a mixture of CO and H2, can be produced from any carbon-based feedstock (hydrocarbons, coal, petroleum coke, biomass). So it has obtained a lot of interest as alternative to olefin production via the methanol-to-olefins (MTO) process or direct Fischer-Tropsch synthesis (FTS). However, these two processe suffer from short catalyst lifetime and selectivity limitation predicted by the Anderson-Schultz-Flory (ASF) model, respectively.
The recently reported direct conversion of syngas to olefin (STO) with bifunctional oxide-zeolite (OX-ZEO) catalysts reaches high C2−C4 selectivity and long catalyst lifetime. However, the chemistry of this new process, in particular the reaction mechanism, is still unclear. So our research interest focus on a detailed mechanism of STO reactions on bifunctional catalysts and substantive evidence for identification of intermediates.
Solid state NMR spectroscopy is a useful tool for the study of heterogeneously catalytic reactions. Especially, advanced in situ techniques has been introduced in studies on the mechanism and dynamics of catalytic reactions. However, these techniques suffer from restricted reaction conditions due to delicate flow MAS probes. We are of great interests in exploring innovative in situ MAS NMR techniques to investigate catalytic reactions in critical conditions, e.g. high temperature and high pressure, and getting insight into the mechanism in catalytic reactions of syngas combined with other analytical methods.