Research team and collaborators of Xu Weilin, Changchun Institute of chemical engineering, Chinese Academy of sciences have made a series of progress in the research on the kinetics and mechanism of efficient energy catalysts

The efficient utilization of precious metals and the substitution of non precious metals for precious metals are two ways to reduce the cost of catalysis, and become the research hotspot in the field of energy catalysis To achieve high dispersion of precious metals and reduce the size of nanoparticles can give full play to the catalytic capacity of each active site, and then improve the utilization of precious metals Metal particles (from large nanoparticles to clusters, to monatoms) have a strong correlation between catalytic performance and size Recently, the research team of Xu Weilin from Changchun Institute of Applied Chemistry, Chinese Academy of Sciences and Professor Xie Jianping from National University of Singapore cooperated Based on gold clusters of different sizes, the size dependent catalytic behavior of gold clusters is monitored in real time at the single cluster level by using single molecule fluorescence microscopy and quantum chemistry calculation It is found that the size dependent catalytic effect of single gold clusters is mainly reflected in the generation and dissociation process of catalytic products The generation of small gold clusters has experienced the competition of Langmuir Hinshelwood Mechanism, but relatively large gold clusters or nanoparticles experience non competitive mechanism These differences can be attributed to the unique quantum size effect of nanoclusters This work was published on PNAs (DOI: 10.1073 / PNAS 1805711115) Figure 1 Kinetics study of different size gold clusters (source: PNAs) when the metal clusters are dispersed to the single atom level of ultra-low load, the metal catalysts will show unexpected catalytic activity due to their unique single atom size effect, geometric structure and electronic characteristics In collaboration with Jiang Zheng and Gulin of Shanghai Institute of Applied Physics, Chinese Academy of Sciences, and Xu Weilin of Changchun Institute of chemical technology, Chinese Academy of Sciences, a nitrogen anchored zinc based catalyst was prepared by simple pyrolysis method It has high electrocatalytic activity for CO 2 electroreduction to CO with Faraday efficiency of 95% and durability of over 75% At the same time, the ultra-low initial overpotential (24 MV) and the ultra-high TOF value (9969 h-1) exceeded most of the catalysts reported so far A series of characterization methods and theoretical calculations confirm that the nitrogen anchored single atom zinc (zn-n4) is the main active site, and the formation of the negative ion of the CO2 radical is the decisive step in the whole process of CO2 electroreduction (Fig 2c, d) The work was published on angelw Chem Int ed (DOI: 10.1002 / anie 201805871) Figure 2 Research on the performance and mechanism of znn 4 / C catalyst (source: angelw Chem Int ed.) these two parts of work extend from the basic research on the dynamics of different size metal clusters to the application of non noble metal monoatomic catalysts In order to provide theoretical support for the further study of the catalytic process in the future and provide new ideas for the design of low-cost metal catalysts with ultra-low loading, we should analyze the catalytic mechanism by means of fine characterization and quantum chemistry theory, and analyze the catalytic nature of small nanoclusters and traditional nanoparticles at the single molecule level This series of work was supported by 973 project and NSFC.