Magnetic Fe 1.3 Ni 0.7 P Aerogels Prepared from Nanoparticle Assembly: The Functional Whole Is the Sum of Its Parts
Magnetic Fe 1.3 Ni 0.7 P Aerogels Prepared from Nanoparticle Assembly: The Functional Whole Is the Sum of Its Parts
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由纳米粒子组装制备的磁性 Fe 1.3 Ni 0.7 P 气凝胶：功能整体是其各部分的总和
DOI：
10.1021/acs.jpcc.1c08709
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Brock, Stephanie L.
中科院分区：
文献类型：
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作者：
Hettiarachchi, Malsha A.;Su’a, Tepora;Ramzan, Ali-hamza;Pokhrel, Shiva;Nadgorny, Boris;Brock, Stephanie L.
以11-巯基十四烷酸（MUA）和1-十二烷硫醇（DDT）为包覆层，将Fe1.3Ni0.7P纳米棒氧化制备三维磁性Fe1.3Ni0.7P纳米棒组件（凝胶和气凝胶），并与离散纳米棒前驱体进行比较，并在与所采用配体基团相关的界面化学特征的背景下评估其磁性。用过氧化氢处理MUA和ddt覆盖的Fe1.3Ni0.7P纳米棒，得到的凝胶在很大程度上保留了孔物质集成网络中纳米棒的结构（通过粉末x射线衍射评估）和形态（通过透射电子显微镜显示）特征。然而，由mua覆盖颗粒制成的气凝胶在乙二胺四乙酸（EDTA）处理后会发生分散，而由ddt覆盖颗粒制成的气凝胶则保持不变。同样，还原退火导致由ddt覆盖的颗粒产生的气凝胶发生解理，而由mua覆盖的颗粒产生的气凝胶保持完整，如果更致密，则反映在表面积减少了约50%。这些数据与两种网络中不同的界面化学性质相一致：由ddt覆盖颗粒制成的气凝胶中无定形的亚磷酸酯/磷酸盐olation键，以及由mua覆盖颗粒制成的气凝胶中亚磷酸酯/磷酸盐olation键和悬垂羧酸盐金属离子交联的组合。离散Fe1.3Ni0.7P纳米颗粒的超顺磁阻断温度（TB）以及由11-MUA和1-DDT交换的纳米颗粒制成的气凝胶都出现在30-40 K范围内，场相关磁化谱（M-H）在50 K时表现出最小的磁滞，矫顽力（HC）值为~ 10 Oe。因此，组成气凝胶网络的Fe1.3Ni0.7xP纳米颗粒的行为是独立的，正如无序的三维组装所期望的那样，磁性气凝胶可以被视为它们各个成分的总和。
Three-dimensional magnetic Fe1.3Ni0.7P nanorod assemblies (gels and aerogels) were prepared by oxidation of Fe1.3Ni0.7P nanorods capped with 11-mercaptoundecanoic acid (MUA) and 1-dodecanethiol (DDT), and their magnetic properties were evaluated in comparison to discrete nanorod precursors and in the context of the interfacial chemical characteristics associated with the ligand group employed. Treatment of MUA- and DDT-capped Fe1.3Ni0.7P nanorods with hydrogen peroxide results in gels that largely retain the structural (as assessed by powder X-ray diffraction) and morphological (as revealed by transmission electron microscopy) features of the nanorods in a pore–matter integrated network. However, aerogels created from MUA-capped particles undergo dispersion upon treatment with ethylenediaminetetraacetic acid (EDTA), whereas those produced from DDT-capped particles remain unchanged. Likewise, reductive annealing resulted in cleavage of the aerogel produced from DDT-capped particles, whereas the aerogels produced from MUA-capped particles remained intact, if more compact, as reflected in a ca. 50% decrease in surface area. The data are consistent with distinct interfacial chemistry in the two networks: amorphous phosphite/phosphate olation linkages in aerogels produced from DDT-capped particles vs a combination of phosphite/phosphate olation linkages and metal-ion cross-linking of pendant carboxylates in aerogels produced from MUA-capped particles. The superparamagnetic blocking temperature (TB) of discrete Fe1.3Ni0.7P nanoparticles, and the aerogels made from 11-MUA and 1-DDT exchanged nanoparticles, all appear in the range 30–40 K, and the field-dependent magnetization profiles (M–H) exhibit minimal hysteresis at 50 K with coercivity (HC) values ∼10 Oe. Thus, the Fe1.3Ni0.7xP nanoparticles comprising the aerogel network behave independently, as expected for a disordered 3-D assembly, and the magnetic aerogels can be regarded as a summation of their individual components.