研究与开发杂志
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国际标准期刊号: 2311-3278
国际标准期刊号: 2311-3278
马利克·凯萨尔·侯赛因
通过液相色谱法在活性药物成分中应用核壳颗粒 Malik Qaisar Hussain 验证制药服务总监，拉合尔，巴基斯坦 摘要 高效液相色谱 (HPLC) 和超高效液相色谱（UHPLC 或 UPLC）是最广泛使用的工具。活性药物成分（API）的研究和常规质量控制。这些技术中最重要的挑战是快速有效的分离。这两种技术因其选择性、高精度和卓越的精度而受到青睐。另一方面，它们也有一些局限性：在某些情况下，传统 HPLC 使用大量有机溶剂，分析时间较长，而且 UHPLC 具有高背压和摩擦加热。为了克服这些限制，科学家们开发出了新型柱状颗粒。一般来说，基于主链的两种不同二氧化硅类型的柱填充材料已用于 HPLC 和 UHPLC。具有完全多孔二氧化硅颗粒的固定相符合分析的基本标准，但这些显示了 HPLC 的所有局限性。然而，近年来，核壳二氧化硅颗粒（实心核和多孔壳的组合）越来越多地用于高效分离，并缩短运行时间。因此，核壳技术提供了与 UHPLC 中使用的亚 2 μm 颗粒相同的高效分离，同时消除了缺点（可能会降低背压）。核壳颗粒的关键因素是多孔壳层的尺寸和厚度，后者可以使用范第姆特方程来解释。核壳纳米结构代表了电化学储能装置应用的独特系统。由于具有高功率输出和长期循环稳定性的独特特性，电化学电容器（EC）已成为最具吸引力的电化学存储系统之一，因为它们可以在储能领域补充甚至替代电池，特别是在高功率情况下需要交付或吸收。本文旨在总结先进超级电容器应用的核壳纳米结构的最新进展，因为它们的分层结构不仅可以创建所需的分层多孔通道，而且还具有更高的电导率和更好的结构机械稳定性。核壳纳米结构包括碳/碳、碳/金属氧化物、碳/导电聚合物、金属氧化物/金属氧化物、金属氧化物/导电聚合物、导电聚合物/导电聚合物，甚至更复杂的三元核壳纳米粒子。总结了ECs核壳材料的制备策略、电化学性能和结构稳定性。详细讨论了核壳纳米结构与电化学性能之间的关系。此外，还提出了核壳纳米材料发展面临的挑战和新趋势。详细讨论了核壳纳米结构与电化学性能之间的关系。此外，还提出了核壳纳米材料发展面临的挑战和新趋势。详细讨论了核壳纳米结构与电化学性能之间的关系。此外，还提出了核壳纳米材料发展面临的挑战和新趋势。
A copper nanowire-graphene (CuNW-G)core-shell nanostructure was successfully synthesized using a low-temperature plasma-enhanced chemical vapor deposition process at temperatures as low as 400 °C for the first time. The CuNW-G core-shell nanostructure was systematically characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman, and X-ray photoelectron spectroscopy measurements. A transparent conducting electrode (TCE) based on the CuNW-G core-shell nanostructure exhibited excellent optical and electrical properties compared to a conventional indium tin oxide TCE. Moreover, it showed remarkable thermal oxidation and chemical stability because of the tight encapsulation of the CuNW with gas-impermeable graphene shells. The potential suitability of CuNW-G TCE was demonstrated by fabricating bulk heterojunction polymer solar cells. We anticipate that the CuNW-G core-shell nanostructure can be used as an alternative to conventional TCE materials for emerging optoelectronic devices such as flexible solar cells, displays, and touch panels.Graphitized carbon-encapsulated palladium (Pd) core-shell nanospheres were produced via pulsed laser ablation of a solid Pd foil target submerged in acetonitrile. The microstructural features and optical properties of these nanospheres were characterized via high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-visible spectroscopy. Microstructural analysis indicated that the core-shell nanostructures consisted of single-crystalline cubic metallic Pd spheres that serve as the core material, over which graphitized carbon was anchored as a heterogeneous shell. The absorbance spectrum of the synthesized nanostructures exhibited a broad (absorption) band at ∼264 nm; this band corresponded to the typical inter-band transition of a metallic system and resulted possibly from the absorbance of the ionic Pd2+. The catalytic properties of the Pd and Pd@C core-shell nanostructures were investigated using the reduction of nitrobenzene to aniline by an excess amount of NaBH4 in an aqueous solution at room temperature, as a model reaction. Owing to the graphitized carbon-layered structure and the high specific surface area, the resulting Pd@C nanostructures exhibited higher conversion efficiencies than their bare Pd counterparts. In fact, the layered structure provided access to the surface of the Pd nanostructures for the hydrogenation reaction, owing to the synergistic effect between graphitized carbon and the nanostructures. Their unique structure and excellent catalytic performance render Pd@C core-shell nanostructures highly promising candidates for catalysis applications.