Directly converting carbon dioxide to linear α-olefins on bio-promoted catalysts

Abstract

Although considerable efforts have been made in converting carbon dioxide to hydrocarbons via hydrogenation processes, precise control of C–C coupling towards heavy olefins remains a challenge. Here we report a carbon dioxide hydrogenation to olefin process that achieves 72% selectivity for alkenes and 50.3% selectivity for C4–18 alkenes, of which formation of linear α-olefins accounts for 80%. The process is catalyzed by carbon-supported iron, commonly used in C–C coupling reactions, with multiple alkali promoters extracted from corncob. The design is based on the synergistic catalysis of mineral elements in biomass enzyme on which carbon dioxide can be directly converted into carbohydrate. The mineral elements from corncob may promote the surface enrichment of potassium, suppressing the secondary hydrogenation of alkenes on active sites. Furthermore, carburization of iron species is enhanced to form more Fe5C2 species, promoting both the reverse water–gas shift reaction and subsequent C–C coupling.