Jie Ziyao, Wang Tian-Yu, Huang Shiyang, Bai Xinpeng, Ma Wenhui, Zhang Guixin, Luo Nan
Department of Electrical Engineering, Tsinghua University, Beijing 100084, China.
Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.
iScience. 2024 Jun 29;27(8):110328. doi: 10.1016/j.isci.2024.110328. eCollection 2024 Aug 16.
Plasmas under atmospheric pressure offer a high-temperature environment for material synthesis, but electrode ablation compromises purity. Here, we introduce an atmospheric-pressure microwave plasma (AMP) operated without electrodes to overcome the existing limitations in pure material synthesis. The distribution of the electrostatic field intensity inside a waveguide during AMP excitation was examined via electrostatic field simulations. The lateral and radial gas temperature distributions were also studied using optical emission spectroscopy. The AMP exhibited a uniform ultrahigh temperature (9,000 K), a large volume (10-10 cm), and a response time on the millisecond level. AMP efficiently synthesized silicon nanoparticles, graphene, and graphene@Si-Fe core-shell nanoparticles within tens of milliseconds, ensuring purity and size control. We propose the "heat impulse" metric for evaluating the plasma characteristics ( , , and ) in material synthesis, extended to other high-temperature plasmas. AMP is compact, cost-effective, and easy to assemble, promising for eco-friendly mass production of pure materials.
大气压下的等离子体为材料合成提供了高温环境，但电极烧蚀会影响纯度。在此，我们引入一种无电极运行的大气压微波等离子体（AMP），以克服纯材料合成中的现有局限性。通过静电场模拟研究了AMP激发过程中波导内静电场强度的分布。还利用光发射光谱研究了横向和径向气体温度分布。AMP表现出均匀的超高温（9000K）、大体积（10 - 10厘米）和毫秒级的响应时间。AMP能在几十毫秒内高效合成硅纳米颗粒、石墨烯和石墨烯@硅 - 铁核壳纳米颗粒，确保纯度和尺寸控制。我们提出了“热脉冲”指标来评估材料合成中的等离子体特性（ ， ，和 ），该指标可扩展到其他高温等离子体。AMP结构紧凑、成本效益高且易于组装，有望用于纯材料的环保大规模生产。
