Universal solvent restructuring induced by colloidal nanoparticles
Universal solvent restructuring induced by colloidal nanoparticles
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DOI：
10.1126/science.1261412
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发表时间：
2015-01
期刊：
影响因子：
56.9
通讯作者：
M. Zobel;R. Neder;S. Kimber
中科院分区：
文献类型：
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作者：
M. Zobel;R. Neder;S. Kimber
纳米颗粒附近的结构化溶剂纳米颗粒在溶液中的物理性质和反应性不仅取决于它们的表面终止，还取决于纳米颗粒产生的界面的存在引起的溶剂排序的变化。佐贝尔等人。使用 X 射线散射研究各种金属和金属氧化物纳米颗粒在各种极性溶剂（醇）和非极性溶剂（正己烷）中的溶剂排序。他们观察到纳米粒子表面附近相对于本体溶剂的有序层增强。这些趋势在很大程度上与表面化学无关，例如将表面基团从羟基变为羧酸盐。科学，本期第 14 页。 292 不同类型纳米粒子表面相距 2 纳米处发现了增强溶剂有序层。胶体纳米粒子用于从催化、能源应用到化妆品等应用，通常嵌入基质中或分散在溶液中。因此，预计发生反应的整个颗粒表面都暴露在外。在这里，我们通过 X 射线对分布函数分析表明，极性和非极性溶剂普遍在纳米粒子周围重组。存在的增强有序层的厚度受分子大小的影响，并且超出纳米颗粒表面最多 2 纳米。这些结果表明，溶剂化纳米颗粒的反应性增强包括颗粒本身尺寸的溶剂化壳的贡献。
Structured solvents near nanoparticles The physical properties and reactivity of nanoparticles in solution depend not only on their surface termination but also on changes in solvent ordering caused by the presence of the interface created by the nanoparticle. Zobel et al. used x-ray scattering to study solvent ordering for a variety of metal and metal-oxide nanoparticles in a variety of polar solvents (alcohols) and a nonpolar solvent (n-hexane). They observed layers of enhanced ordering near the nanoparticle surface relative to the bulk solvent. These trends were largely independent of surface chemistry, such as changing the surface groups from hydroxyls to carboxylates. Science, this issue p. 292 Layers of enhanced solvent order are found up to 2 nanometers away from the surfaces of different types of nanoparticles. Colloidal nanoparticles, used for applications from catalysis and energy applications to cosmetics, are typically embedded in matrixes or dispersed in solutions. The entire particle surface, which is where reactions are expected to occur, is thus exposed. Here, we show with x-ray pair distribution function analysis that polar and nonpolar solvents universally restructure around nanoparticles. Layers of enhanced order exist with a thickness influenced by the molecule size and up to 2 nanometers beyond the nanoparticle surface. These results show that the enhanced reactivity of solvated nanoparticles includes a contribution from a solvation shell of the size of the particle itself.