A hydrophobic FeMn@Si catalyst increases olefins from syngas by suppressing C1 by-products.

Although considerable efforts have been made in the selective conversion of syngas [carbon monoxide (CO) and hydrogen] to olefins through Fischer-Tropsch synthesis (FTS), ~50% of the converted CO is transformed into the undesired one-carbon molecule (C1) by-products [carbon dioxide (CO2) and methane (CH4)]. In this study, a core-shell FeMn@Si catalyst with excellent hydrophobicity was designed to hinder the formation of CO2 and CH4 The hydrophobic shell protected the iron carbide core from oxidation by water generated during FTS and shortened the retention of water on the catalyst surface, restraining the side reactions related to water. Furthermore, the electron transfer from manganese to iron atoms boosted olefin production and inhibited CH4 formation. The multifunctional catalyst could suppress the total selectivity of CO2 and CH4 to less than 22.5% with an olefin yield of up to 36.6% at a CO conversion of 56.1%.