Nat. Commun.: Lu Qi's team of Tsinghua University has made a breakthrough in the study of series catalytic electrochemical reduction of carbon dioxide to methane

Recently, the research team led by Lu Qi, associate professor of the industrial catalysis center of the Department of chemical engineering, Tsinghua University, published a report entitled "computational and experimental studies of one pot tandem catalysis for electronic carbon dioxide electrochemical reduction" in nature communications Doi: 10.1038/s41467-019-11292-9) With the rapid development of industry, the use of a large number of fossil fuels has led to the increase of carbon dioxide concentration in the atmosphere year by year, and the following environmental problems, such as greenhouse effect, desertification and so on, have gradually attracted people's attention A very promising solution is to use renewable energy, such as solar energy, tidal energy, etc., to convert carbon dioxide into high value-added chemical products, such as methane, ethylene, ethanol, etc by electrochemical means Electrocatalytic reduction of carbon dioxide can not only effectively reduce the carbon dioxide content in the atmosphere, but also provide a storage solution for these renewable energy sources However, there is still no reliable catalyst to achieve this process efficiently In order to develop efficient catalysts, it is very important to study the reaction mechanism of this process Figure 1 (a) density functional calculation model; (b) energy surface of carbon monoxide migration on the electrode surface; (c) reduction mechanism of carbon monoxide migration on the electrode surface (source: Official Website of Tsinghua University), The mechanism of the series reaction in the electrochemical reduction of carbon dioxide is described, that is, the reduction process of carbon dioxide can be divided into two consecutive steps and optimized respectively Firstly, carbon dioxide is reduced to carbon monoxide by using highly selective catalyst (such as gold, silver, etc.) as substrate, and then carbon monoxide is reduced to required chemical products by catalyst (copper) supported on the substrate In order to clarify this theoretical model, the researchers first proved that the carbon dioxide produced by the substrate can spontaneously and rapidly migrate to the copper catalyst supported on the substrate through the density functional theory calculation; the copper catalyst supported can also realize the electrocatalytic reduction of carbon monoxide under a certain voltage to obtain methane Furthermore, the first mock exam is based on the guidance of computational chemistry, and the feasibility of the model is verified by electrochemical experiments By using the tandem reaction mechanism, the researchers were able to convert carbon dioxide into methane at an efficiency of nearly 60%, which nearly doubled compared with the direct reduction of carbon dioxide In order to further confirm the surface process of series reaction mechanism, in-situ total reflection surface enhanced infrared spectroscopy was used to study the electrochemical process At low voltage, the special absorption peak of carbon monoxide can be observed by the composite electrode material, but it can not be observed by the single electrode material The series reaction mechanism in the experimental model is confirmed from the perspective of spectrum In this work, the feasibility of the series reaction mechanism in the electrochemical reduction of carbon dioxide is clarified through the design of density functional calculation and the corresponding experimental model, coupled with the in-situ infrared spectrum for surface characterization, which provides a new idea for the study of the reaction mechanism of chemical reduction of carbon dioxide, catalyst design and reactor optimization The first co authors of this paper are Zhang HaoChen, a 2017 level doctoral student in the Department of chemical engineering of Tsinghua University, and Chang Xiaoxia, a postdoctoral student in the Department of chemical engineering of the University of Delaware Professor Jingguang g Chen of Columbia University and Professor William A Goddard III of Caltech participated in the research The co authors of this paper are Xu Bingjun, associate professor, Department of chemical engineering, University of Delaware, Zheng Mucheng, associate professor, Department of chemistry, Taiwan University of success, and Lu Qi, associate professor, Department of chemical engineering, Tsinghua University The research work was supported by national key R & D plan and NSFC.