The role of intermediate CoxMn1−xO (x = 0.6–0.85) nanocrystals in the formation of active species for the direct production of lower olefins from syngas

Abstract

Cobalt–manganese (CoMn) oxides obtained through a one-pot synthesis can be controllably reduced to Co_xMn_1−xO nanocrystals for the direct production of C₂–C₄ olefins with high selectivity (50.9 mol%) from syngas at high CO conversion (92.4%), higher than predicted by the Anderson–Schulz–Flory distribution. The formed Co_xMn_1−xO is the key to generating an active Co₂C quadrangular nanoprism phase with (101) and (020) exposed facets in-situ during the reaction, which plays a pivotal role in the high lower-olefin yield. No deactivation was observed after 100 hours under harsh high-conversion reaction conditions, and the activity is one order of magnitude higher than that of the traditional cobalt catalyst.