Patelli Nicola, Migliori Andrea, Morandi Vittorio, Pasquini Luca
Department of Physics and Astronomy, Alma Mater Studiorum Università di Bologna, Viale Berti-Pichat 6/2, 40127 Bologna, Italy.
Section of Bologna, Institute of Microelectronics and Microsystems, National Research Council, Via Gobetti 101, 40129 Bologna, Italy.
Nanomaterials (Basel). 2019 Feb 6;9(2):219. doi: 10.3390/nano9020219.
Metallic nanoparticles (NPs), either supported on a porous oxide framework or finely dispersed within an oxide matrix, find applications in catalysis, plasmonics, nanomagnetism and energy conversion, among others. The development of synthetic routes that enable to control the morphology, chemical composition, crystal structure and mutual interaction of metallic and oxide phases is necessary in order to tailor the properties of this class of nanomaterials. With this work, we aim at developing a novel method for the synthesis of metal/oxide nanocomposites based on the assembly of NPs formed by gas phase condensation of metal vapors in a He/O₂ atmosphere. This new approach relies on the independent evaporation of two metallic precursors with strongly different oxidation enthalpies. Our goal is to show that the precursor with less negative enthalpy gives birth to metallic NPs, while the other to oxide NPs. The selected case study for this work is the synthesis of a Fe-Co/TiO nanocomposite, a system of great interest for its catalytic and magnetic properties. By exploiting the new concept, we achieve the desired target, i.e., a nanoscale dispersion of metallic alloy NPs within titanium oxide NPs, the structure of which can be tailored into TiO or TiO₂ by controlling the synthesis and processing atmosphere. The proposed synthesis technique is versatile and scalable for the production of many NPs-assembled metal/oxide nanocomposites.
金属纳米颗粒（NPs），无论是负载在多孔氧化物框架上还是精细分散在氧化物基质中，都在催化、等离子体激元学、纳米磁性和能量转换等领域有应用。为了定制这类纳米材料的性能，开发能够控制金属相和氧化物相的形态、化学成分、晶体结构以及相互作用的合成路线是必要的。通过这项工作，我们旨在开发一种基于在He/O₂气氛中通过金属蒸汽气相冷凝形成的纳米颗粒组装来合成金属/氧化物纳米复合材料的新方法。这种新方法依赖于两种具有截然不同氧化焓的金属前驱体的独立蒸发。我们的目标是表明，焓值较不负值的前驱体产生金属纳米颗粒，而另一种产生氧化物纳米颗粒。这项工作选择的案例研究是合成Fe-Co/TiO纳米复合材料，这是一个因其催化和磁性性能而备受关注的体系。通过利用这个新概念，我们实现了预期目标，即在二氧化钛纳米颗粒内实现金属合金纳米颗粒的纳米级分散，通过控制合成和加工气氛，其结构可以调整为TiO或TiO₂。所提出的合成技术对于生产许多纳米颗粒组装的金属/氧化物纳米复合材料具有通用性和可扩展性。
