Effects of ionic liquids on the characteristics of synthesized nano Fe(0) particles.
Effects of ionic liquids on the characteristics of synthesized nano Fe(0) particles.
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DOI：
10.1021/ic901559y
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发表时间：
2009-10
影响因子：
4.6
通讯作者：
Yang Zhao;Guirong Cui;Jianji Wang;M. Fan
中科院分区：
文献类型：
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作者：
Yang Zhao;Guirong Cui;Jianji Wang;M. Fan
在离子液体（ILs）水溶液中，利用氯化铁水合物与硼氢化钠的化学还原反应，制备了具有特殊形态和高还原活性的高比表面积零价铁(0)纳米颗粒。离子液体,(C (4) mim) X (X = Cl (-), Br (-), BF (4) (-), PF(6)(-))和[C (n) mim] [BF (4)] (n = 4, 6, 8),是用于此目的。利用透射电子显微镜、x射线衍射和布鲁诺尔-埃米特-泰勒表面积测量来表征制备的Fe(0)的形貌、结构和物理性质。结果表明，Fe(0)的成核和生长受il控制的还原反应机制控制。考察了离子液体（阳离子、阴离子和浓度）对Fe(0)形貌的影响。结果表明，离子液体的阴离子对Fe(0)的形貌和尺寸起关键作用，不同离子液体下制备的Fe(0)的纳米颗粒尺寸呈现如下趋势：[C(4)mim]Cl > [C(4)mim]Br > [C(4)mim][BF(4)] > [C(4)mim][PF(6)]和[C(4)mim][BF(4)] > [C(6)mim][BF(4)] > [C(8)mim][BF(4)]。通过亚硝酸钠的反硝化实验，研究了铁纳米颗粒的还原活性。il包封的Fe(0)对亚硝酸盐的去除率明显快于未包封的Fe(0)。这表明il包覆的Fe(0)颗粒是还原性降解的较好候选物。铁(0)纳米颗粒的高还原活性归因于其高表面积和更多的活性位点。
In this paper, high specific surface area zerovalent Fe(0) nanoparticles with unusual morphology and high reductive activity were prepared using a chemical reductive reaction of iron chloride hydrate with sodium borohydride in an aqueous solution of ionic liquids (ILs). The ionic liquids, [C(4)mim]X (X = Cl(-), Br(-), BF(4)(-), PF(6)(-)) and [C(n)mim][BF(4)] (n = 4, 6, 8), were used for this purpose. Transmission electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller surface area measurements were used to characterize the morphology, structure, and physical properties of the as-prepared Fe(0). The results suggest that the nucleation and growth of the Fe(0) were governed by an IL-controlled reductive reaction mechanism. The effects of ionic liquids (cations, anions, and concentration) on the morphology of the Fe(0) were examined. It was shown that anions of the ILs played a key role in the morphology and size of Fe(0), and the nanoparticle size of the Fe(0) prepared in the presence of different ionic liquids follows the trend: [C(4)mim]Cl > [C(4)mim]Br > [C(4)mim][BF(4)] > [C(4)mim][PF(6)] and [C(4)mim][BF(4)] > [C(6)mim][BF(4)] > [C(8)mim][BF(4)]. The reductive activity of the iron nanoparticles was studied by the denitrification experiment of sodium nitrite. The removal rate of nitrite by the IL-capped Fe(0) was found to be much faster than that by the noncapped Fe(0). This indicates that the IL-capped Fe(0) particles are better candidates for the reductive degradation. The high reductive activity of the Fe(0) nanoparticles was attributed to their high surface area and more active sites.