Controlling the Nature of Etched Si Nanostructures: High- versus Low-Load Metal-Assisted Catalytic Etching (MACE) of Si Powders
Controlling the Nature of Etched Si Nanostructures: High- versus Low-Load Metal-Assisted Catalytic Etching (MACE) of Si Powders
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DOI：
10.1021/acsami.9b20514
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发表时间：
2020-01-29
影响因子：
9.5
通讯作者：
Riikonen, Joakim
中科院分区：
文献类型：
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作者：
Tamarov, Konstantin;Swanson, Joseph D.;Riikonen, Joakim
金属辅助催化蚀刻（MACE）是制备硅纳米线（Si NWs）的一种简便方法。我们发现，随着Ag催化剂负载的改变，受MACE影响的Si颗粒的结构发生了巨大的变化。以乙酸为表面活性剂，适量注入AgNO3 (aq)，可促进银的沉积。醋酸的使用和H2O2的受控注入不仅有助于蚀刻步骤的优化，而且还使我们能够确定以前未观察到的蚀刻制度，我们称之为低负荷MACE （LL-MACE）。与常规生产的材料相比，LL-MACE生产的材料具有显着不同的屈服和结构特性。我们展示了从廉价的冶金级硅粉中生产Si NWs和介孔Si纳米颗粒。高载银（HL-MACE）产生平行蚀刻轨迹孔，由银纳米颗粒的相关运动产生。在蚀刻过程中，银纳米颗粒的均匀尺寸分布（主要是70-100 nm）是动态产生的。这些蚀刻轨迹孔的壁很容易被超声搅拌劈裂，形成Si NWs。低银负载（LL-MACE）产生10-50 nm的银纳米颗粒，以不相关（随机定向）的方式蚀刻，产生类似于4和13-21 nm的介孔双峰分布。使用注射器泵输送氧化剂（H2O2）和Ag+对于提高产品均匀性和产量至关重要。不同的工艺温度和等级的硅产生显著不同的孔径分布。这些结果有助于生产出产量高、成本低、性能可控的Si NWs和介孔纳米颗粒，这些纳米颗粒适用于锂离子电池、药物输送、生物医学成像和对比度增强等领域。
Metal-assisted catalytic etching (MACE) involving Ag deposited on Si particles has been reported as a facile method for the production of Si nanowires (Si NWs). We show that the structure of Si particles subjected to MACE changes dramatically in response to changing the loading of the Ag catalyst. The use of acetic acid as a surfactant and controlled injection of AgNO3 (aq) enhanced Ag deposition. The use of acetic acid and controlled injection of H2O2 not only facilitated optimization of the etching step but also allowed us to identify a previously unobserved etching regime that we denote as low-load MACE (LL-MACE). Material produced by LL-MACE exhibits dramatically different yield and structural characteristics as compared to conventionally produced material. We demonstrate the production of Si NWs as well as mesoporous Si nanoparticles from an inexpensive metallurgical-grade Si powder. High loading of Ag (HL-MACE) generates parallel etch track pores created by the correlated motion of Ag nanoparticles. The uniform size distribution (predominantly 70-100 nm) of the Ag nanoparticles is generated dynamically during etching. The walls of these etch track pores are cleaved readily by ultrasonic agitation to form Si NWs. Low loading of Ag (LL-MACE) creates 10-50 nm Ag nanoparticles that etch in an uncorrelated (randomly directed) fashion to generate a bimodal distribution of mesoporosity peaking at similar to 4and 13-21 nm. The use of a syringe pump to deliver the oxidant (H2O2) and Ag+ is essential for increased product uniformity and yield. Different process temperatures and grades of Si produced significantly different pore size distributions. These results facilitate the production of Si NWs and mesoporous nanoparticles with high yield, low cost, and controlled properties that are suitable for applications in, e.g., lithium-ion batteries, drug delivery, as well as biomedical imaging and contrast enhancement.