Synthesis and Catalytic Application of Ag44 Clusters Supported on Mesoporous Carbon
Synthesis and Catalytic Application of Ag44 Clusters Supported on Mesoporous Carbon
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DOI：
10.1021/acs.jpcc.5b08903
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发表时间：
2015-11
影响因子：
3.7
通讯作者：
Masaru Urushizaki;Hirokazu Kitazawa;Shinjiro Takano;Ryo Takahata;S. Yamazoe;T. Tsukuda
中科院分区：
文献类型：
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作者：
Masaru Urushizaki;Hirokazu Kitazawa;Shinjiro Takano;Ryo Takahata;S. Yamazoe;T. Tsukuda
4-(氟苯基)硫醇保护的Ag44簇合物(Ph4P)4[Ag44(SC6H4F)30][Ag44(SC6H4F)30]在300~500℃真空下在介孔碳(MPC)上焙烧2 h，X射线吸收光谱、透射电子显微镜和热脱附质谱表明，在300℃焙烧[Ag44(SC6H4F)30]4-得到了无硫的Ag44簇合物，与十二硫醇保护的银纳米粒子(3.0±0.6 nm)的形成形成了鲜明对比。将Ag44/MPC用于氨-硼烷(NH3BH3)催化脱氢反应。结果表明，Ag44/MPC催化剂仅在氧气存在下由NH3BH3生成1当量的氢气(循环频率1.9×103h-1Ag原子-1)。考虑到其他金属(铂、钯、Rh、镍或Ru)的纳米颗粒在惰性气氛中生成3当量的氢气，这一结果表明Ag44/MPC催化的NH3BH3脱氢反应是以不同于其他金属纳米颗粒的机理进行的。
4-(Fluorophenyl)thiolate-protected Ag44 clusters (Ph4P)4[Ag44(SC6H4F)30] were calcined on mesoporous carbon (MPC) under vacuum at 300–500 °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– at 300 °C, in sharp contrast to the formation of silver sulfide nanoparticles by the calcination of dodecanethiolate-protected Ag nanoparticles (3.0 ± 0.6 nm). Ag44/MPC was applied in the catalytic dehydrogenation of ammonia–borane (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 × 103 h–1 Ag atom–1). 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 oth...