Highly selective one-step CO2 conversion to liquid alcohols through plasma synergistic MOFs catalysis

Abstract

Low-temperature plasma (LTP) assisted catalysis enables not only the conversion of CO2 into liquid products under mild conditions, but also significant enhancement in catalytic efficiency through plasma-catalyst synergy. In this study, an efficient plasma synergistic catalytic system was developed. By incorporating amino functional groups and active metals into the metal-organic frameworks (MOF) and coupling it with LTP, the system not only significantly improved the reaction efficiency but also successfully directed the product selectivity by regulating the key reaction intermediates. After regulation, the catalyst demonstrated a performance with 27.1% CH4 conversion, 22.7% CO2 conversion, and 53.9% selectivity toward liquid products. In the liquid products, the total selectivity toward alcohols reached 39%, with alcohols thus accounting for 72.3% of them. Notably, C3 alcohols with a selectivity of 2.5% were detected for the first time. Using plasma-coupled in-situ infrared spectroscopy, the control mechanism of the reaction pathway was revealed. This mechanism, analogous to a “molecular shunt switch”, regulated the transformation between the main reaction paths. Specifically, the initial pathway involved the gradual hydrogenation of CO to alcohols. However, upon the introduction of -NH2 groups, the pathway shifted to the coupling of OH and CHx. The subsequent addition of Co reversed this shift, causing the CO hydrogenation pathway to re-dominated. Furthermore, Co and -NH2 were found to regulate the formation and consumption of CH3O. This control mechanism provides insights and guidance for the design of new catalysts.