Dynamic confinement catalysis in Fe-based CO2 hydrogenation to light olefins

Abstract

Hydrogenation of CO2 into light olefins is an important route to carbon neutrality. Most of traditional researches focus on the catalyst component, structure, and promoter to enhance the selectivity of light olefins while ignoring the diffusion of products. Here, we report a NaFeZr-MOR composite catalyst for light olefin synthesis in CO2 hydrogenation via pore confinement. The selectivity in hydrocarbons and STY (Space-time yields) of C2–4= is gradually increasing maximum up to 51.3% and 12.2 (mmol·gcat−1.h−1), which lie in a high level among reported Fe-based catalysts. Further characterization revealed that the essence of selectivity change period is the accumulation and evolution of carbonaceous species, which causes the change of product diffusion behavior. It suppresses the escape of heavy hydrocarbons from MOR pores, leading to an increased light olefin, especially ethylene, which is called “dynamic confinement”. These findings provide a new insight for controlling low-carbon product selectivity in CO2 hydrogenation.