【Frontiers in HaiChuan Technology】Dalian Institute of Chemical Physics achieves efficient catalytic synthesis of ethanol from syngas using iron oxides

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Dalian Institute of Chemical Physics achieves efficient catalytic synthesis of ethanol from syngas using iron oxides. Release date: 2024-12-18. Recently, the research team led by Researcher Sun Jian from the Group for Carbon Resources, Small Molecules, and Hydrogen Energy Utilization (DNL1905 Group) in the Department of Hydrogen Energy and Advanced Materials at our institute made new progress in the study of synthesizing ethanol from syngas via the hydrogenation of dimethyl oxalate (DMO). They designed an iron oxide catalyst that can generate Fe3O4 in situ during the catalytic process; this compound acts as the main active site to drive the deep hydrogenation of DMO, resulting in an ethanol yield of 90% while maintaining good stability throughout the reaction. The hydrogenation of dimethyl oxalate can selectively produce high-value chemicals such as ethylene glycol, ethanol, methyl glycolate, and methyl acetate; it is one of the important pathways for converting syngas into oxygen-containing compounds. Among them, the reaction for synthesizing ethanol can provide a viable approach for the clean utilization of coal resources and the diversified production of ethanol. However, traditional copper-based catalysts suffer from issues such as numerous by-products, low efficiency, stringent reaction conditions, and poor stability during the reaction process. Sun Jian’s team has been dedicated for a long time to the conversion and utilization of small molecules derived from carbon-containing resources such as CO2 and syngas. They have carried out systematic research in the area of synthesizing oxygen-containing compounds via DMO hydrogenation or direct synthesis of syngas (Sci. Adv., 2018 ； ACS Catal., 2021 ； Appl. Catal. B: Environ., 2022 ； Chem Catal., 2023). In this work, the team designed a series of iron oxide catalysts with different crystal phases, which can generate ferric tetraoxide and iron carbide in situ during the reaction, achieving a reaction conversion rate of 100% and an ethanol selectivity of over 90%, thereby enabling the efficient synthesis of ethanol from dimethyl oxalate. The team further elucidated the structure-activity relationship of the catalyst and the mechanism by which iron species are involved in the hydrogenation of C=O bonds. The results show that the catalyst particle size can influence the product distribution in the hydrogenation of dimethyl oxalate by affecting factors such as the degree of reduction and surface adsorption behavior, thereby impacting the evolution of iron active species. Contrary to the traditional view that Cu species or metal carbides serve as the primary active sites, this study proposes that the active phase dominated by iron oxides can facilitate the deep hydrogenation step, and a higher Fe3O4/Fe5C2 ratio is favorable for the formation of ethanol. This study provides new insights for the design of catalysts for selective hydrogenation of C=O bonds. The relevant results were published recently in ACS Catalysis under the title “Iron O*des Oriented Ethanol Synthesis via Dimethyl Oxalate Hydrogenation from Syngas”. The first author of this article is Sun Yannan, a doctoral student in Group DNL1905 at my institute. This work is supported by projects such as the **Key Research and Development Program**, the National Natural Science Foundation, and the Open Fund for the Joint Energy and Chemical Engineering Project of the Liaoning Binhai Laboratory.