95-64-7Relevant articles and documents
Subnanometer Bimetallic Platinum–Zinc Clusters in Zeolites for Propane Dehydrogenation
Cheng, Jun,Fan, Qiyuan,Jia, Ran,Jiang, Zheng,Li, Lin,Mayoral, Alvaro,Miao, Shu,Sun, Qiming,Terasaki, Osamu,Wang, Ning,Wang, Ye,Xu, Jun,Yang, Dong-Chun,Yang, Ruoou,Yu, Jihong,Zeng, Lei,Zhang, Jichao,Zhang, Peng,Zhang, Qinghong,Zhang, Tianjun,Zhou, Wei
, p. 19450 - 19459 (2020)
Propane dehydrogenation (PDH) has great potential to meet the increasing global demand for propylene, but the widely used Pt-based catalysts usually suffer from short-term stability and unsatisfactory propylene selectivity. Herein, we develop a ligand-protected direct hydrogen reduction method for encapsulating subnanometer bimetallic Pt–Zn clusters inside silicalite-1 (S-1) zeolite. The introduction of Zn species significantly improved the stability of the Pt clusters and gave a superhigh propylene selectivity of 99.3 % with a weight hourly space velocity (WHSV) of 3.6–54 h?1 and specific activity of propylene formation of 65.5 mol (Formula presented.) gPt?1 h?1 (WHSV=108 h?1) at 550 °C. Moreover, no obvious deactivation was observed over PtZn4?S-1-H catalyst even after 13000 min on stream (WHSV=3.6 h?1), affording an extremely low deactivation constant of 0.001 h?1, which is 200 times lower than that of the PtZn4/Al2O3 counterpart under the same conditions. We also show that the introduction of Cs+ ions into the zeolite can improve the regeneration stability of catalysts, and the catalytic activity kept unchanged after four continuous cycles.
Impregnating Subnanometer Metallic Nanocatalysts into Self-Pillared Zeolite Nanosheets
Wang, Ning,Sun, Qiming,Zhang, Tianjun,Mayoral, Alvaro,Li, Lin,Zhou, Xue,Xu, Jun,Zhang, Peng,Yu, Jihong
, p. 6905 - 6914 (2021)
Impregnation is the most commonly used approach to prepare supported metal catalysts in industry. However, this method suffers from the formation of large metal particles with uneven dispersion, poor thermal stability, and thus unsatisfied catalytic performance. Here, we demonstrate that the self-pillared MFI zeolite (silicalite-1 and ZSM-5) nanosheets with larger surface area and abundant Si-OH groups are ideal supports to immobilize ultrasmall monometallic (e.g., Rh and Ru) and various bimetallic clusters via simple incipient wetness impregnation method. The loaded subnanometric metal clusters are uniformly dispersed within sinusoidal five-membered rings of MFI and remain stable at high temperatures. The Rh/SP-S-1 is highly efficient in ammonia borane (AB) hydrolysis, showing a TOF value of 430 molH2 molRh-1 min-1 at 298 K, which is more than 6-fold improvement over that of nanosized zeolite-supported Rh catalyst and even comparable with that of zeolite-supported Rh single-atom catalyst. Because of the synergistic effect between bimetallic Rh-Ru clusters and zeolite acidity, the H2 generation rate from AB hydrolysis over Rh0.8Ru0.2/SP-ZSM-5-100 reaches up to 1006 molH2 molmetal-1 min-1 at 298 K, and also shows record activities in cascade hydrogenation of various nitroarenes by coupling with the hydrolysis of AB. This work demonstrates that zeolite nanosheets are excellent supports to anchor diverse ultrasmall metallic species via the simple impregnation method, and the obtained nanocatalysts can be applied in various industrially important catalytic reactions.
C-H Amination of Arenes with Hydroxylamine
See, Yi Yang,Sanford, Melanie S.
supporting information, p. 2931 - 2934 (2020/04/09)
This Letter describes the development of a TiIII-mediated reaction for the C-H amination of arenes with hydroxylamine. This reaction is applied to a variety of electron-rich (hetero)arene substrates, including a series of natural products and pharmaceuticals. It offers the advantages of mild conditions (room temperature), fast reaction rates (30 min), compatibility with ambient moisture and air, scalability, and the use of inexpensive commercial reagents.
