【Frontiers in HaiChuan Chemical Technology】Scientists develop nanobiological coatings that can efficiently convert carbon dioxide into fuel

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Scientists at the National University of Singapore have coated copper catalysts with a biopolymer film only 2 to 5 nanometers thick, thereby making the process of converting carbon dioxide into high-value fuels such as ethylene more efficient and environmentally friendly. The related paper was published in the latest issue of the journal Nature Energy. Electrochemical carbon dioxide reduction refers to the process of using electrical energy to convert carbon dioxide into high-value chemicals or fuels rich in carbon (such as ethanol and ethylene). It is not only a key technology for achieving carbon neutrality but also helps with the storage of renewable energy. Copper is currently the most common and effective catalyst. However, to enable copper to produce mainly polycarbonate products rather than simple hydrogen, the chemical environment on the catalyst surface must be carefully controlled, which usually requires the addition of perfluoro and polyfluoroalkyl substances such as Nafion. But this added substance is a \"persistent chemical\" associated with health problems such as weakened immunity and an increased risk of certain cancers. Recent research has shown that these biopolymer coatings derived from biological waste such as seafood shells and wood achieve the same results through a completely different mechanism. By utilizing advanced spectroscopic techniques and computational models, the team discovered that the coating can concentrate carbon dioxide on the surface of the catalyst, restrict the movement of water to suppress side reactions, and simultaneously promote efficient ion transport. These factors collectively suppress the production of hydrogen, thereby favoring the formation of high-value products such as ethylene and ethanol. The team stated that this research not only demonstrates new approaches to improving electrochemical carbon dioxide reduction but also shows that technologies relying on permanent chemicals could be replaced by cellulose, chitin, and chitosan derived from seafood shells, insect exoskeletons, wood, or dead leaves. The experimental results showed that with the new cellulose coating, at a current density of 1.6 amperes per square centimeter, the yield of polycarbonate products was as high as 95% ； Even at a high current density of 2.2 amperes per square centimeter (where the reaction rate is faster but more hydrogen byproduct is generated), the yield of polycarbonate products can still be maintained at 83%. This shows that biopolymer coatings still perform excellently under harsh industrial conditions. Furthermore, biopolymers can completely replace Nafion. By weight, high-quality chitosan costs only one thousandth of that of Nafion. If this technology is scaled up, it is expected to significantly reduce costs.