[Ocean Chemical Science and Technology Frontier] my country has achieved high-efficiency production of low-carbon olefins under mild conditions!

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Recently, the team of researchers Sun Jian and Ge Qingjie of Dalian Institute of Chemical Physics, Chinese Academy of Sciences (hereinafter referred to as "Dalian Institute of Chemical Physics") has made important progress in producing low-carbon olefins from synthesis gas. The team proposed a new catalytic strategy based on the Fischer-Tropsch synthesis system, achieving efficient conversion of synthesis gas into light olefins under mild conditions (250–260°C, 0.1 MPa). The relevant results were published in Nature on April 1, Beijing time. Fischer-Tropsch synthesis is an important industrial process for preparing fuels and chemicals using synthesis gas (carbon monoxide and hydrogen) as raw materials. It is used in countries where coal resources are abundant but oil resources are relatively scarce. * * It has important application value. my country's energy structure is characterized by "rich coal, poor oil, and little gas". The development of conversion technology using syngas as an intermediate is of great significance to ensuring energy security and promoting the diversification of chemical raw materials. The traditional Fischer-Tropsch synthesis olefins process usually needs to operate at temperatures above 300 °C and pressures greater than 2 MPa, which results in relatively high energy consumption and cost. At the same time, under mild conditions, there is a trade-off between conversion rate and low-carbon olefin selectivity in the reaction system. That is, as the conversion rate increases, the low-carbon olefin selectivity often decreases significantly, making it still challenging to achieve high selectivity of low-carbon olefins under high conversion rate (>60%) conditions. In order to solve the above problems, this study started from the intrinsic mechanism of the reaction and found that the introduction of specific hydrophilic hydroxyl additives can have a positive impact on carbon monoxide activation, providing a new perspective for understanding and regulating the synthesis gas conversion reaction. Studies have found that introducing specific hydroxyl additives into the sodium-cobalt-manganese catalytic system can build a reaction interface rich in surface hydroxyl groups, induce the formation of new catalytic sites for cobalt-manganese composite oxides with a low-symmetry triclinic phase structure, and improve the activation efficiency of carbon monoxide. Under mild conditions of 250–260°C and 0.1 MPa, the catalytic system can achieve a carbon monoxide conversion rate of 80% in a wide hydrogen-to-carbon ratio range, a low-carbon olefin selectivity of 60%, and a total olefin selectivity of over 80%. Structural characterization and mechanism studies show that hydroxyl promoters can inhibit excessive reduction and carbonization of the catalyst, stabilize the active oxide phase, and optimize the synergistic relationship between carbon monoxide activation and carbon-carbon coupling from the source, providing new experimental basis for understanding the dynamic evolution of multi-phase active structures during the catalytic conversion of carbon monoxide/carbon dioxide. In the future, the team will continue to promote relevant basic research and application exploration around key issues such as the construction method of the carbon monoxide/carbon dioxide catalytic conversion system controlled by hydroxyl additives, the evolution of the active site structure and the optimization of the reaction process, so as to provide favorable technical support for the clean and efficient utilization of coal and the development of low-carbon chemical processes in my country.