New approach found to convert carbon dioxide into liquid fuel

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New Approach to Converting Carbon Dioxide into Liquid Fuel Author/Source: Date: 2016-01-08 Views: 199 On January 7, 2016, the research teams led by Professor Xie Yi and Professor Sun Yongfu from the School of Chemistry and Materials Science at the University of Science and Technology of China, as well as the Hefei Laboratory of Microscale Science and Technology, published a study in the journal Nature on the electrocatalytic reduction of carbon dioxide using hybrid two-dimensional ultra-thin structures, offering a new method for converting carbon dioxide into liquid fuel. 　　In the past, activating carbon dioxide required a large amount of energy. Since the beginning of this century, the massive emission of greenhouse gases such as carbon dioxide as a result of industrialization has led to an accelerating rate of global warming ； On the other hand, the massive consumption of non-renewable fossil fuels has sounded the alarm for a global energy crisis. To address these two major threats, scientists have been seeking various practical technologies in recent years to reverse the process of carbon dioxide release resulting from fossil fuel combustion, thereby reducing carbon dioxide emissions and alleviating some energy shortages. 　　“The catalytic conversion of carbon dioxide can be achieved through various methods such as photocatalysis, electrocatalysis, photoelectrocatalysis, and hydrogen integration. Our research group’s work focuses only on the mechanistic studies of electrocatalytic reduction of carbon dioxide, rather than aiming to improve its performance. ”Yesterday, Xie Yi said in a telephone interview with reporters that the electrocatalytic reduction process can convert carbon dioxide into various hydrocarbon fuel molecules, yielding fuels such as methane, formic acid, and methanol. However, carbon dioxide is very stable, and one of the bottlenecks in the electroreduction of carbon dioxide is how to activate this highly stable molecule, which often requires a very high overpotential ； Moreover, the presence of overpotential not only wastes a large amount of energy but also often leads to a selective reduction of the reduction products. 　　Generally, catalysts made from precious metals possess high catalytic activity, but their high cost severely limits their widespread use. To this end, scientists are searching for various relatively inexpensive metal catalysts. 　　The coexistence of ultra-thin structures and metal oxides is more advantageous. Previous studies have shown that metal catalysts obtained through the reduction of metal oxides exhibit higher catalytic activity compared to those prepared by other methods, and they can even reduce the reduction potential for carbon dioxide to its thermodynamic minimum. “However, it has not been clear up to now why these surface metal oxides can enhance electrocatalytic performance. This is mainly because the catalysts prepared in the past contained a large number of microstructures such as interfaces and defects; the presence of these microstructures tends to obscure the effect of the surface metal oxides on the catalyst’s own metal catalytic properties, making it difficult to determine clearly the role of each component. ”Xie Yi said. 　　To this end, the research team developed a hybrid model material system, namely a few-atom-layer-thick metal-metal oxide hybrid ultrathin structure, which is characterized by a clear model, extreme thinness of the material, and a high abundance of surface-active atoms. Studies have found that surface cobalt atoms confined in ultra-thin structures exhibit higher intrinsic catalytic activity and greater product selectivity at lower overpotentials compared to those in bulk materials, and partial oxidation of the cobalt atom layer further enhances their intrinsic catalytic activity. 　　“In other words, metal atoms may exhibit higher catalytic conversion activity when arranged in specific patterns and at certain oxidation states; that is, the presence of ultra-thin two-dimensional structures and metal oxides enhances the ability to catalytically reduce carbon dioxide. ”Xie Yi said. 　　However, converting “clean” carbon dioxide into hydrocarbon fuels is not something that can be achieved overnight; there is still a long way to go before it can be put into practical use. Xie Yi said that many scholars around the world are currently conducting research on the catalytic conversion of carbon dioxide, but such research is still at the purely fundamental stage. Xie Yi also said that there are many difficulties to overcome in the practical application of carbon dioxide beyond the catalytic conversion process. These include the need to capture and concentrate carbon dioxide in the air before conversion, as well as the separation of the products produced after conversion; there are still numerous technical barriers in these areas. http://www.nmtech.com.cn/*nwen_xgyw_xx.asp?path=58&id=174708