Platinum nanoparticle shape effects on benzene hydrogenation selectivity
Platinum nanoparticle shape effects on benzene hydrogenation selectivity
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DOI：
10.1021/nl0716000
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发表时间：
2007-10-01
期刊：
影响因子：
10.8
通讯作者：
Somorjai, Gabor A.
中科院分区：
文献类型：
--
作者：
Bratlie, Kaitlin M.;Lee, Hyunjoo;Somorjai, Gabor A.
在由不同形状的纳米铂（立方和立方）和十四烷基三甲基溴化铵（TTAB）组成的表面单层存在下，研究了苯的加氢反应。红外光谱分析表明，TTAB通过烷基链的弱C-H中心点中心点Pt键与Pt表面结合。纳米颗粒的形状对催化选择性有很大影响。环己烷和环己烯产物分子在立方纳米颗粒上都能形成，而环己烷只在立方纳米颗粒上生成。这些结果与早期研究中在Pt（111）和Pt（100）单晶上得到的产物选择性相同。在立方纳米颗粒上生成环己烷的表观活化能为10.9 +/- 0.4 kcal/mol，而在立方面体纳米颗粒上生成环己烷和环己烯的表观活化能分别为8.3 +/- 0.2和12.2 +/- 0.4 kcal/mol。这些激活能较低，相应的周转率比单晶铂表面高3倍。
Benzene hydrogenation was investigated in the presence of a surface monolayer consisting of Pt nanoparticles of different shapes (cubic and cuboctahedral) and tetradecyltrimethylammonium bromide (TTAB). Infrared spectroscopy indicated that TTAB binds to the Pt surface through weak C-H center dot center dot center dot Pt bond of the alkyl chain. The catalytic selectivity was found to be strongly affected by the nanoparticle shape. Both cyclohexane and cyclohexene product molecules were formed on cuboctahedral nanoparticles, whereas only cyclohexane was produced on cubic nanoparticles, These results are the same as the product selectivities obtained on Pt(111) and Pt(100) single crystals in earlier studies. The apparent activation energy for cyclohexane production on cubic nanoparticles is 10.9 +/- 0.4 kcal/mol, while for cuboctahedral nanoparticles, the apparent activation energies for cyclohexane and cyclohexene production are 8.3 +/- 0.2 and 12.2 +/- 0.4 kcal/mol, respectively. These activati on energies are lower, and corresponding turnover rates are three times higher than those obtained with single-crystal Pt surfaces.