The reporter learned from the University of Science and Technology of China that the team of Professor Lu Junling and the team of Professor Li Weixue, for the first time, revealed the modulation law of the geometric effect and the electronic effect on the catalytic reaction with the size of the metal nanocatalyst for the first time, creatively A strategy to separate the geometric and electronic effects of stripped metal particles was proposed-"oxide selective encapsulation" of metal nanoparticles. In the platinum-catalyzed selective oxidation of benzyl alcohol to benzaldehyde with important application background, high activity and high selectivity conversion are achieved.
Because the geometric and electronic structures of metal nano-catalyst particles change synchronously with their sizes, it is impossible to effectively distinguish the contribution of the two structural effects to the catalytic activity, selectivity, and size dependence. How to reveal the inherent nature of the size effect of metal catalysts, break the strong correlation between geometric structure effect and electronic structure effect and particle size, and then optimize the design of better performance catalysts is a major challenge in the field of heterogeneous catalysis.
The researchers found that on particles larger than 4 nanometers and smaller than 4 nanometers, geometric effects and electronic effects control the performance of the dominant reaction, respectively, so that the selectivity and activity of the catalytic reaction show a "volcanic" change trend with the particle size. On this basis, the low coordination atoms of the 4 nanoparticles are "selectively encapsulated by oxides", which effectively suppresses the occurrence of side reactions and obtains a catalyst with high specific mass activity and high selectivity.
The strategy of "oxide selective encapsulation" of metal nanoparticles proposed in this work not only effectively resolves the geometric and electronic effects of stripped metal particles, but also breaks the "volcanic" curve of catalytic performance with particle size. This strategy provides an effective means for understanding the geometric and electronic effects in catalytic reactions and provides important guidance for the design of metal catalysts with high activity and selectivity. (Reporter Wu Changfeng)
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