CHEMICAL SCIENCE

The research on the mechanism of carbon dioxide reduction reaction has been breakthrough


Schematic diagram of the instrumentation used for CO2 reduction and reaction product monitoring, wherein the upper left corner is the CO2 generating CO reaction equation through different paths, * represents the catalyst.

Schematic diagram of the reaction mechanism of CO2 reduction to CO under the condition of Cu(I) catalyst and water presence: (a) the reaction process of CO2 reduction to CO is deduced by experimental observation of the intermediates and products, and (b) the energy barrier change pattern of the co2 conversion process of the intermediate under the condition of singlet state is calculated by density functional theory. Courtesy of the author of the paper

The increase in greenhouse gas emissions such as carbon dioxide is one of the most important factors causing global warming, so it is of great strategic and practical significance to effectively reduce emissions and comprehensively utilize carbon dioxide. Direct conversion of carbon dioxide into high value-added chemicals has long been a challenge in the field of catalysis, and a deep understanding of the carbon dioxide reduction process at the molecular level is critical to improving its conversion and selectivity. Although many spectroscopic methods and theoretical calculation models have been developed for the study of carbon dioxide conversion processes, there is still insufficient experimental evidence to explain its reaction mechanism, thus limiting the improvement of carbon dioxide conversion efficiency.

Recently, The team of Professor Zhang Zhiping of the School of Chemistry and Chemical Engineering of Xi’an Shiyou University has made important progress in the study of the reaction mechanism of carbon dioxide reduction, and the relevant work was published in Nature Communications.

Zhang Zhiping introduced that in this research work, through the transformation of commodity instruments, they cleverly used the first stage quadrupole of the triple quadrupole mass spectrometer as a real-time separator of specific catalyst ions, the second stage quadrupole as a microreactor of the carbon dioxide reduction process, the third stage quadrupole transmitted the intermediates and products involved in the reaction to the detector online, using isotope labeled compounds as the tracer of the reaction, through the special design of the mass spectrometer gas path system. The reaction mechanism of reducing carbon dioxide to carbon monoxide is explained in detail by directly separating the catalyst copper ions and their complex ions from atmospheric ionization sources and interacting with carbon dioxide gas online, and through the online capture of reaction intermediates and products under various experimental conditions and isotope comparison experiments.

According to the traditional view, the O atoms in carbon dioxide reduction into carbon monoxide are derived from carbon dioxide. In the study, the authors found that the O atoms in the reduction reaction to generate carbon monoxide came from the coordinated water molecules on the surface of the catalyst of the reaction system, not from the carbon dioxide itself. This conclusion applies not only to the on-line reaction process of substances, but also to the electrocatalytic reduction reaction of actual carbon dioxide and the inverse reaction process of industrial water and gas, indicating that the discovery has a certain universality. Also found compared to the metal catalyst Cu+, when[Cu(H2O)]+ When used as a catalyst, the reaction efficiency of carbon dioxide reduced to carbon monoxide can be increased by two orders of magnitude.

It is understood that in order to explore the reaction process in depth, Professor Zhang Zhiping’s team elaborated on carbon dioxide by modifying the mass spectrometer to capture the reaction intermediates, isotope comparison experiments and calculations of density functional theory[Cu(H2O)]+ Mechanism for the formation of carbon monoxide under catalytic action.

Experts in this research field believe that this work not only provides a methodological basis for in-depth elaboration of the mechanism of carbon dioxide reduction, but also provides a focus for a detailed understanding of the role of water in the process of carbon dioxide reduction.

It is reported that the research work has been funded by the National Natural Science Foundation of China, the Shaanxi Provincial Outstanding Youth Fund, and the Shaanxi University Youth Innovation Team. (Source: China Science Daily, Zhang Xingyong, Zhao Xijun)

Related paper information:https://doi.org/10.1038/s41467-022-30289-5



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