【Frontiers in HaiChuan Chemical Technology】The Ordos Laboratory achieves a major breakthrough in the field of high-hydrogen atom-economical olefin synthesis

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The Ordos Laboratory has made a significant breakthrough in the field of olefin synthesis with high hydrogen atom economy. Recently, the Ordos Laboratory, in collaboration with Tsinghua University, carried out research on \"producing olefins from syngas with high hydrogen atom economy,\" aiming to explore innovative approaches and key technologies to improve the hydrogen atom efficiency in this process. The results of this research were published in the world’s top comprehensive academic journal, Science. This is the first time since the establishment of the Ordos Laboratory that academic research results have been published in a top international academic journal. The technology for directly producing olefins from syngas, as an emerging catalytic approach, utilizes multifunctional catalysts to integrate reactions such as water-gas shift, syngas to methanol conversion, and methanol to olefins. This enables significant shortening of the production process, reduction in investment costs, as well as lower consumption of materials and energy. Traditional olefin synthesis requires a hydrogen-to-carbon ratio (H₂/CO) of >2, which results in large amounts of CO₂ emissions from coal-based syngas in the water-gas shift stage ； At the same time, the hydrogen and oxygen elements in the raw materials are mostly converted into water, which is equivalent to turning expensive hydrogen gas into wastewater, resulting in a waste of resources. The team developed a sodium-modified FeCₓ@Fe₃O₄ core-shell catalyst that integrates the two functions of water-gas shift and syngas-to-olefins conversion at the microscale interface. By utilizing the water-gas shift reaction, the water generated during the reaction is converted in situ into hydrogen for reuse in olefin synthesis, thereby increasing the hydrogen atom economy of the target product to 66%~86% and significantly suppressing the excessive oxidation of the catalyst by water. The hydrogen atom economy of this technology far exceeds that of traditional routes – the theoretical hydrogen atom economy of the conventional water-gas shift-methanol synthesis (hydrogen-to-carbon ratio of 2–2.05)–methanol to olefins route is 50%, while the actual value is 43%–47%. Through isotope tracing experiments and experiments to block the water-gas shift pathway, the team not only confirmed the effectiveness of this coupling mechanism but also quantitatively determined the contribution of the water-gas shift reaction on the catalyst, laying a foundation for the rational design of such catalysts. “The high hydrogen atom economy is closely related to the matching degree of activity between the two reaction functions of the catalyst. The water-gas shift reaction can be initiated at lower temperatures, whereas the olefin production reaction requires higher temperature conditions for activity. ”A responsible official from the Ordos Laboratory stated that under reaction conditions of 350°C and 2 MPa, using raw materials with a hydrogen-to-carbon ratio of 1.5, the one-pass conversion rate of CO can reach approximately 95%, the selectivity for olefins exceeds 75% (based on hydrocarbon products), and the yield of hydrocarbons is 33 wt% (based on the raw materials) ； After 500 hours of continuous reaction testing, the catalyst maintained stable performance.