Rapid Self-Assembly of Metal/Polymer Nanocomposite Particles as Nanoreactors and Their Kinetic Characterization
Rapid Self-Assembly of Metal/Polymer Nanocomposite Particles as Nanoreactors and Their Kinetic Characterization
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DOI：
10.3390/nano9030318
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发表时间：
2019-02-28
期刊：
影响因子：
5.3
通讯作者：
Tang, Christina
中科院分区：
文献类型：
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作者：
Harrison, Andrew;Vuong, Tien T.;Tang, Christina
自组装金属纳米粒子-聚合物纳米复合粒子作为纳米反应器是一种很有前途的以水为主体溶剂进行液相反应的方法。在这项工作中，我们展示了快速，可扩展的自组装金属纳米粒子催化剂-聚合物纳米复合粒子通过闪速纳米沉淀。催化剂的负载和纳米复合粒子的大小可以独立调节。以纳米复合粒子为纳米反应器，以4-硝基苯酚的还原为模型反应，研究了反应与扩散的基本相互作用。诱导时间受试剂添加顺序、添加间隔时间和试剂浓度的影响。综上所述，我们的实验表明，硼氢化钠的扩散对诱导时间影响最大。在诱导时间之后，用核磁共振测量的标度分析和有效扩散系数表明，观察到的反应速率是反应限制而不是扩散限制。此外，本构动力学与无配体金纳米颗粒相当。这一结果表明聚合物微环境不会使催化剂活性位点失活或阻断。
Self-assembled metal nanoparticle-polymer nanocomposite particles as nanoreactors are a promising approach for performing liquid phase reactions using water as a bulk solvent. In this work, we demonstrate rapid, scalable self-assembly of metal nanoparticle catalyst-polymer nanocomposite particles via Flash NanoPrecipitation. The catalyst loading and size of the nanocomposite particles can be tuned independently. Using nanocomposite particles as nanoreactors and the reduction of 4-nitrophenol as a model reaction, we study the fundamental interplay of reaction and diffusion. The induction time is affected by the sequence of reagent addition, time between additions, and reagent concentration. Combined, our experiments indicate the induction time is most influenced by diffusion of sodium borohydride. Following the induction time, scaling analysis and effective diffusivity measured using NMR indicate that the observed reaction rate are reaction- rather than diffusion-limited. Furthermore, the intrinsic kinetics are comparable to ligand-free gold nanoparticles. This result indicates that the polymer microenvironment does not de-activate or block the catalyst active sites.