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首页> 外文期刊>Catalysis science & technology >Catalytic activity of shaped platinum nanoparticles for hydrogenation: a kinetic study
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Catalytic activity of shaped platinum nanoparticles for hydrogenation: a kinetic study

机译：形状铂纳米颗粒的催化活性用于氢化：动力学研究

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摘要

Aqueous-phase hydrogenation of 4-nitrophenoi (4-NP) was investigated in the presence of freestanding or supported Pt nanoparticles (NPs) of various shapes. Uniform cubic and pseudo-tetrahedral Pt NPs with sub-10 nm sizes were obtained by the direction of bio-inspired small molecules, 3-hydroxybutyric acid (3-HB) and tropic acid (TA), respectively. The catalytic activity is found to be strongly affected by the nanoparticle shape and the support, SBA-15. Pseudo-tetrahedral Pt NPs directed by TA have superior activity to the cubic ones with 3-HB. But when loaded on SBA-15, cubic Pt(3-HB) NPs showed better performance than Pt(TA) NPs. Then the experimental data are fitted to a Langmuir-Hinshelwood (L-H) model involving a surface reaction controlling mechanism for 4-NP hydrogenation. This model follows a dual-site adsorption with molecular adsorption of 4-NP and dissociative adsorption of hydrogen. The results show that the reaction catalyzed by pseudo-tetrahedral Pt(TA) NPs has lower apparent activation energy than that by the cubic Pt(3-HB) NPs. But after loading these NPs onto SBA-15, the apparent activation energy of Pt(3~HB)@SBA-15 decreased while that of Pt(TA)@SBA-15 increased in comparison with their corresponding free-standing NPs.
机译：在存在各种形状的独立或支持的PT纳米颗粒（NP）的情况下研究了4-硝基苯酚（4-NP）的水相氢化。分别通过生物启发的小分子，3-羟基丁酸（3-hb）和热带酸（TA）的方向获得了均匀的立方体和伪四面体PT NP。发现该催化活性受纳米颗粒形状和支持SBA-15的强烈影响。由TA指挥的伪四面体PT NP具有比具有3 hb的立方体活性。但是，当在SBA-15上加载时，立方PT（3 hb）NP的性能比PT（TA）NP更好。然后将实验数据拟合到涉及4-NP氢化的表面反应控制机制的Langmuir-Hinshelwood（L-H）模型。该模型遵循双位点吸附，并具有4-NP的分子吸附和氢的解离吸附。结果表明，伪四面体PT（TA）NP催化的反应具有比立方PT（3-hb）NP的反应能量低。但是将这些NP加载到SBA-15上后，PT（3〜Hb）@SBA-15的明显激活能量降低，而PT（TA）@SBA-15的活化能与相应的独立式NP相比增加。

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