Direct conversion of CO2-Containing syngas to higher oxygenates over a CoMn│ZnFe2O4 multifunctional catalyst

The highly selective conversion of CO 2 -containing syngas to higher oxygenates (C 2+ OH), while achieving CO/CO 2 co-conversion, remains a fundamental challenge. In this work, we developed a series of multifunctional catalysts based on CoMn and ZnFe 2 O 4 with various coupling configurations. By precisely regulating the synergistic coupling of elementary reaction steps, we have successfully achieved the conversion of CO 2 -containing syngas while avoiding the removal of CO 2 . Specifically, the CoMn(up)|ZnFe 2 O 4 (down) catalyst achieved 32.2% and 14.8% of CO and CO 2 conversion, yielding 41.5% oxygenate selectivity with a C 2+ OH/ROH fraction of 91.2%. Furthermore, the catalyst exhibited exceptional stability over a 240 h continuous run. The study reveals that the suitable CO 2 concentration (<12%) promotes the formation of C 2+ oxygenates, whereas high CO 2 concentrations negatively affect the C–C coupling. Catalyst characterization and mechanistic studies demonstrate that a small amount of CO 2 enhances the formation of formate and carbonate intermediates on the catalyst surface. In CO/CO 2 hydrogenation, the multifunctional catalyst provides an additional pathway, in which the C–C coupling proceeds via the reaction between CH x ∗ alkyl species generated on the CoMn component and CH 3 O∗ methoxy intermediates formed on the ZnFe 2 O 4 catalyst surface.