Olefins such as ethene and propene are important basic chemicals that are closely related to people's daily life. China is a big consumer country for olefins, which mainly rely on petroleum as the raw materials.
At the beginning of the 20th century, German scientists Franz Fischer and Hans Tropsch developed a technology for converting coal into liquid fuels—the so-called Fischer-Tropsch synthesis (FTS). It has become a core technology for coal-to-liquid and gas-to-liquid. However, it is challenged by its wide distribution of hydrocarbons and consumption of a large amount of water.
The research team led by Prof. BAO Xinhe, member of the Chinese Academy of Sciences, and Prof. PAN Xiulian from the Dalian Institute of Chemical Physics (DICP) developed a composite catalyst, which is composed of metal oxides with interface-confined coordination unsaturated active sites and zeolites with confined nanopores. This bifunctional catalyst enables direct conversion of coal-based synthesis gas to light olefins.
The composite catalyst affords two types of active sites with complementary properties. The partially reduced oxide surface (ZnCrOx) activates CO and H2, and C–C coupling is subsequently manipulated within the confined acidic pores of zeolites. Thus, the surface polymerization of CHx is circumvented and it leads to a high selectivity of light olefins (80%) and light hydrocarbons C2-C4 (94%) at a carbon monoxide (CO) conversion of 17%.
This work was published in Science on March 4, 2016.