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].