Preparation of Reinforced Anisometric Patchy Supraparticles for Self-Propulsion,Particle & Particle Systems Characterization

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Preparation of Reinforced Anisometric Patchy Supraparticles for Self-Propulsion
Particle & Particle Systems Characterization ( IF 2.7 ) Pub Date : 2021-05-05 , DOI: 10.1002/ppsc.202000328
H. Esra Oguztürk ₁ , Leona J. Bauer ₂ , Ioanna Mantouvalou ₂ , Birgit Kanngieβ er ₂ , Orlin D. Velev ₃ , Michael Gradzielski ₁

Affiliation

The preparation of fumed silica-based anisometric supraparticles with well-defined catalytically active patches suitable for self-propulsion is presented here. These sub-millimeter-sized particles can self-propel as they contain Pt-covered magnetite (Fe₃O₄) nanoparticles, where the Pt can decompose catalytically a “fuel” like H₂O₂ and thereby propel the supraparticles. By their magnetic properties, the catalytically active nanoparticles can be concentrated in patches on the supraparticle surface. The goal is to obtain robust supraparticles with well-defined patchiness and long-time stability during self-propulsion through evaporation-induced self-assembly (EISA) on a superhydrophobic surface. The latter is a major issue as oxygen evolution can lead to the disintegration of the supraparticles. Therefore, enhanced mechanical stability is sought using a number of different additives, where the best results are obtained by incorporating polystyrene microspheres followed by heat treatment or reinforcement with microfibrillated cellulose (MFC) and sodium trisilicate (Na₂SiO₃). The detailed internal structure of the different types of particles is investigated by confocal micro-X-ray fluorescence spectroscopy (CMXRF), which allows for precisely locating the catalytic Fe₃O₄@Pt nanoparticles within the supraparticles with a resolution in the µm range. The insights on the supraparticle structure, together with their long-time stability, allow fabricating optimized patchy supraparticles for potential applications in propulsion-enhanced catalysis.

中文翻译：

用于自推进的增强型不等距片状超粒子的制备

这里介绍了气相二氧化硅基不等轴超粒子的制备，该粒子具有明确的催化活性贴片，适用于自推进。这些亚毫米大小的颗粒可以自我推进，因为它们包含 Pt 覆盖的磁铁矿 (Fe ₃ O ₄ ) 纳米颗粒，其中 Pt 可以催化分解“燃料”，如 H ₂ O ₂从而推动超粒子。通过它们的磁性，催化活性纳米粒子可以集中在超粒子表面上的补丁中。目标是通过超疏水表面上的蒸发诱导自组装（EISA）在自推进过程中获得具有明确定义的斑块和长期稳定性的坚固超粒子。后者是一个主要问题，因为析氧会导致超粒子的分解。因此，需要使用多种不同的添加剂来提高机械稳定性，其中最好的结果是通过加入聚苯乙烯微球然后热处理或用微纤化纤维素 (MFC) 和三硅酸钠 (Na ₂ SiO ₃）。通过共聚焦微 X 射线荧光光谱 (CMXRF) 研究了不同类型颗粒的详细内部结构，它允许以微米范围的分辨率精确定位超颗粒内的催化 Fe ₃ O ₄ @Pt 纳米颗粒。对超粒子结构的深入了解以及它们的长期稳定性，可以制造优化的片状超粒子，以用于推进增强催化的潜在应用。

更新日期：2021-06-20

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