[Haichuan Chemical Technology] Chinese scientists achieve the direct conversion of carbon dioxide in the air into urea products that can be collected in an aqueous phase

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According to reports from December 4th, in the field of research on the utilization of carbon dioxide resources, it is of great scientific significance and engineering value to find ways to avoid the energy-intensive processes of capture and purification, and to achieve direct conversion of CO2 derived from real-world environments such as air and flue gases. This approach is crucial for advancing practical artificial carbon cycle processes. However, in the real environment, the CO2 concentration is extremely low and it coexists with large amounts of oxygen; as a result, its photo/electrocatalytic reduction process is often inhibited by the oxygen reduction reaction. Therefore, achieving the preferential reduction of CO2 under conditions of low concentration and oxygen presence has always been a major scientific challenge on an international scale. With the support of the National Natural Science Foundation of China, the Ministry of Science and Technology, and the Chinese Academy of Sciences, the research group led by Sheng Hua from the Photochemistry Laboratory of the Institute of Chemistry, Chinese Academy of Sciences, has recently made new breakthroughs in the direct photocatalytic conversion of airborne CO2, based on a CO2 in-situ capture-and-conversion mechanism driven by hydroxylation sites. The research team utilized two types of indium active sites in the indium porphyrin metal–organic framework (In–MOF), which have different affinities for CO2/O2, to achieve \"spatially segregated reduction\" of CO2 and O2. This strategy eliminates the competitive inhibition of oxygen reduction on CO2 reduction, instead promoting CO2 reduction kinetically, thereby creating a special oxygen-enhanced CO2 reduction system. Further coupling of In–MOF with UIO-66-NH2 to form a heterojunction can create a \"dual enrichment\" effect at the catalytic sites for low-concentration CO2, thereby enabling the direct photocatalytic reduction of air CO2 to CO. On this basis, the team developed a floating photocatalytic platform capable of operating in natural environments, by integrating a newly reported approach for the catalytic synthesis of urea via the coupling of CO and ammonia (Angew. Chem. Int. Ed., 2025, 64, e202505630). This platform is capable of coupling air CO2 reduction with aqueous ammonia oxidation under sunlight and in open-air conditions, thereby directly converting air CO2 into urea products that can be collected in an aqueous phase. https://p3-sign.toutiaoimg.com/tos-cn-i-axegupay5k/b297a19885e04a9abbf907f0584a5a79~tplv-tt-origin-web:gif.jpeg?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1765532321&x-signature=QuooTUGtHevZtS65HpH447ttLJQ%3D The reaction pathways and potential applications of an integrated system for air CO2 capture, conversion, and product recovery are presented. This research not only provides new catalytic strategies and reaction systems for the efficient utilization of air CO2 as a resource, but also demonstrates the potential of photocatalytic technology in the coordinated conversion of carbon and nitrogen in open environments as well as in the synthesis of sustainable resources. The relevant research findings were published on November 25 in Nature Communications 2025,16,10493. The first author of the paper is doctoral student Zhang Zhiyong, while the corresponding author is Researcher Sheng Hua.