Palladium and Ruthenium Dual‐Single‐Atom Sites on Porous Ionic Polymers for Acetylene Dialkoxycarbonylation: Synergetic Effects Stabilize the Active Site and Increase CO Adsorption

• Published in: Angewandte Chemie International Edition 2023-08, Vol.62 (33), p.e202307570-n/a
• Main Authors: Li, Xingju, Wang, Jiaqian, Yuan, Qiao, Song, Xiangen, Mu, Jiali, Wei, Yao, Yan, Li, Sun, Fanfei, Feng, Siquan, Cai, Yutong, Jiang, Zheng, Han, Zhongkang, Ding, Yunjie
• Format: Article
• Language: English
• Subjects: Acetylene; Adsorption; Alkyne Dialkoxycarbonylation; Carbon monoxide; Catalysts; Dual-Single-Atom Sites; First Principles Calculations; Industrial applications; Palladium; PD-1 protein; Polymers; Porous Ionic Polymers; Ruthenium; Stability
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202307570

Heterogeneous single‐metal‐site catalysts usually suffer from poor stability, thereby limiting industrial applications. Dual Pd1−Ru1 single‐atom‐sites supported on porous ionic polymers (Pd1−Ru1/PIPs) were constructed using a wetness impregnation method. The two isolated metal species in the form of a binuclear complex were immobilized on the cationic framework of PIPs through ionic bonds. Compared to the single Pd‐ or Ru‐site catalyst, the dual single‐atom system exhibits higher activity with 98 % acetylene conversion and near 100 % selectivity to dialkoxycarbonylation products, as well as better cycling stability for ten cycles without obvious decay. Based on DFT calculations, it was found that the single‐Ru site exhibited a strong CO adsorption energy of −1.6 eV, leading to an increase in the local CO concentration of the catalyst. Notably, the Pd1−Ru1/PIPs catalyst had a much lower energy barrier of 2.49 eV compared to 3.87 eV of Pd1/PIPs for the rate‐determining step. The synergetic effect between neighboring single sites Pd1 and Ru1 not only enhanced the overall activity, but also stabilized PdII active sites. The discovery of synergetic effects between single sites can deepen our understanding of single‐site catalysts at the molecular level. A heterogeneous Pd1−Ru1 dual‐single‐atoms catalyst supported on porous ionic polymers was fabricated via a wet impregnation method and applied in acetylene dialkoxycarbonylation. The molecular structure of the Pd1−Ru1 catalyst was determined to be [P]+−[PdI3−I−RuCl2(CO)3]−, with a synergetic effect between the neighboring Pd1 and Ru1 single sites elevating the overall activity and stabilizing the active site.