Synthesis and Catalytic Application of Ag44 Clusters Supported on Mesoporous Carbon

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• 作者：Masaru Urushizaki ; Hirokazu Kitazawa ; Shinjiro Takano ; Ryo Takahata ; Seiji Yamazoe ; Tatsuya Tsukuda
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：December 10, 2015
• 年：2015
• 卷：119
• 期：49
• 页码：27483-27488
• 全文大小：325K
• ISSN：1932-7455

文摘

4-(Fluorophenyl)thiolate-protected Ag₄₄ clusters (Ph₄P)₄[Ag₄₄(SC₆H₄F)₃₀] were calcined on mesoporous carbon (MPC) under vacuum at 300鈥?00 掳C for 2 h. X-ray absorption spectroscopy, transmission electron microscopy, and thermal-desorption mass spectrometry revealed that sulfur-free Ag₄₄ clusters were successfully produced by the calcination of [Ag₄₄(SC₆H₄F)₃₀]^{4鈥?/sup> at 300 掳C, in sharp contrast to the formation of silver sulfide nanoparticles by the calcination of dodecanethiolate-protected Ag nanoparticles (3.0 卤 0.6 nm). Ag₄₄/MPC was applied in the catalytic dehydrogenation of ammonia鈥揵orane (NH₃BH₃) as a test reaction. It turned out that the Ag₄₄/MPC catalysts produced 1 equiv of H₂ from NH₃BH₃ but only in the presence of O₂ (turnover frequency 1.9 脳 103 h鈥? Ag atom鈥?). Given that nanoparticles of other metals (Pt, Pd, Rh, Ni, or Ru) produced 3 equiv of H₂ under an inert atmosphere, this result indicates that the Ag₄₄/MPC-catalyzed dehydrogenation of NH₃BH₃ proceeds by a different mechanism from that on other nanoparticles.}