Core Viewpoint - The research highlights a novel approach to reduce CO2 emissions in Fischer-Tropsch synthesis for olefins production by introducing trace levels of halogen compounds, specifically bromomethane, into the iron-based catalytic system, achieving near-zero CO2 generation and high selectivity for olefins [2][3][5]. Group 1 - The study demonstrates that adding 20 ppm of bromomethane (CH3Br) to the iron carbide catalyst can reduce CO2 selectivity to below 1% while increasing olefin selectivity to approximately 85% among all carbon products [5]. - The halogen's surface interaction with iron active sites inhibits pathways that lead to CO2 generation and olefin hydrogenation, thus enhancing carbon efficiency in the synthesis process [3][5]. - This "halogen regulation" strategy offers a simple, scalable, and widely applicable method for carbon-efficient syngas conversion [6]. Group 2 - Another concurrent study from Tsinghua University developed a sodium-modified FeCx@Fe3O4 core-shell catalyst that couples water-gas shift and syngas to olefins synthesis, achieving high olefin selectivity and hydrocarbon yield while reducing CO2 emissions and water by-products [7]. - Both studies utilize iron-based catalysts to generate olefins from syngas with significantly lower CO2 emissions through different strategies [9].

Core Viewpoint - The article discusses a significant breakthrough in the conversion of syngas to olefins, focusing on a newly developed sodium-modified FeC x @Fe 3 O 4 core-shell catalyst that enhances hydrogen atom economy (HAE) and reduces environmental impact [2][3][7]. Group 1: Research Development - The research introduces a catalyst that combines water-gas shift (WGS) and syngas to olefins (STO) reactions, addressing the low HAE caused by water by converting it back to hydrogen [3][5]. - Under conditions of 623 K and 2 MPa, the catalyst achieves a CO conversion rate of approximately 95%, olefin selectivity exceeding 75%, and a hydrocarbon yield of 33% over a 500-hour test period [5]. Group 2: Environmental Impact - The new WGS-STO coupling route significantly reduces steam consumption, wastewater generation, and CO2 emissions, lowering the overall environmental impact by 46% compared to the traditional WGS-MTO route [7]. - The HAE of the new catalyst ranges from approximately 66% to 86%, which is substantially higher than the 43% to 47% achieved by conventional methods [5][7]. Group 3: Comparative Studies - The article also mentions concurrent research from Peking University and the Shanxi Coal Chemistry Research Institute, which achieved near-zero CO2 emissions and high olefin selectivity using a different strategy involving bromomethane in iron-based catalytic systems [8][10].