Synthesis and Microstructural Analysis of Homogeneously Dispersed Nickel Nanoparticles in Amorphous Silica
Synthesis and Microstructural Analysis of Homogeneously Dispersed Nickel Nanoparticles in Amorphous Silica
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DOI：
10.1111/j.1551-2916.2011.04897.x
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发表时间：
2012-02
影响因子：
3.9
通讯作者：
Y. Ikuhara;Tomohiro Saito;Seiji Takahashi;Y. Sasaki;T. Hirayama
中科院分区：
文献类型：
--
作者：
Y. Ikuhara;Tomohiro Saito;Seiji Takahashi;Y. Sasaki;T. Hirayama
采用前驱体溶液法合成了含有均匀分散的Ni纳米颗粒的二氧化硅，包括热处理和还原阶段，并系统地研究了Si-Ni-O前驱体向复合粉末的转化，以确定纳米颗粒的形成机制。在热处理过程中，发现氧化镍纳米颗粒与Si-O网络同时形成，因为烷氧基配体的分解和NiO纳米颗粒的成核都在约300°C下发生。离子结合的Si-Oδ--Niδ+单元的形成在将NiO锚定在Si-O网络中并阻碍进一步的晶体生长方面发挥着关键作用。此外，在SiO中分散的NiO的复合物中Si-O2−-Ni 2+相互作用的形成延缓了NiO的还原，导致由Si-O基质中高度分散的金属Ni纳米颗粒组成的特征微结构。这种镍-二氧化硅复合材料预期显示出增强的可逆氢吸附，使其对于用于具有高氢选择性的分离膜具有吸引力。
Silica containing uniformly dispersed Ni nanoparticles has been synthesized by a precursor solution method, involving heat treatment and reduction stages, and the transformation of the Si–Ni–O precursor into the composite powder has been investigated systematically to determine the formation mechanism of the nanoparticles. During heat treatment, nickel oxide nanoparticles are found to form simultaneously with the Si–O network, as decomposition of the alkoxy ligand and nucleation of NiO nanoparticles, both occur at around 300°C. The formation of ionically bound Si–Oδ−–Niδ+ units plays a key role in anchoring the NiO in the Si–O network and impeding further crystalline growth. Moreover, the formation of the Si–O2−–Ni2+ interactions in the composite of dispersed NiO in SiO retard the reduction of NiO, resulting in a characteristic microstructure consisting of highly dispersed metallic Ni nanoparticles within an Si–O matrix. This nickel–silica composite is expected to show enhanced reversible hydrogen adsorption, making it attractive for use in separation membranes with high hydrogen selectivity.