Post-Plasma SiO(x) Coatings of Metal and Metal Oxide Nanoparticles for Enhanced Thermal Stability and Tunable Photoactivity Applications.
Post-Plasma SiO(x) Coatings of Metal and Metal Oxide Nanoparticles for Enhanced Thermal Stability and Tunable Photoactivity Applications.
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DOI：
10.3390/nano6050091
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发表时间：
2016-05-13
期刊：
影响因子：
--
通讯作者：
Borra JP
中科院分区：
文献类型：
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作者：
Post P;Jidenko N;Weber AP;Borra JP
介绍了在连续化学气相沉积（CVD）工艺中，用氧化硅直接包覆气体颗粒的等离子体气溶胶工艺。结果表明，在大气压下介质阻挡放电（DBD）诱导的非热等离子体细丝会引发DBD后的气相反应。首先扫描DBD操作条件以产生臭氧和五氧化二氮。在选定的条件下，这些等离子体与DBD下游的气态正硅酸四乙酯（TEOS）前体反应。然后，气态中间体在纳米颗粒表面凝结，自反应生成均匀的固体SiOx涂层，厚度从纳米到微米不等。这证实了dbd后注入有机硅前驱体的兴趣，以实现活性物质的稳定生产，随后控制SiOx涂层的厚度。实现了球形和球状金属和金属氧化物纳米粒子（Pt, CuO, TiO2）的SiOx涂层。在所选择的DBD操作条件下，球形纳米颗粒镀层的厚度取决于反应时间和前驱体浓度。对于铂团块，可以调整操作条件以优先覆盖初级颗粒之间的颗粒间接触区，将铂团块的烧结温度提高到比通常烧结温度高得多的温度。介绍了涂层团块在增强热稳定性和可调光活性方面的潜在应用。
The plasma-based aerosol process developed for the direct coating of particles in gases with silicon oxide in a continuous chemical vapor deposition (CVD) process is presented. It is shown that non-thermal plasma filaments induced in a dielectric barrier discharge (DBD) at atmospheric pressure trigger post-DBD gas phase reactions. DBD operating conditions are first scanned to produce ozone and dinitrogen pentoxide. In the selected conditions, these plasma species react with gaseous tetraethyl orthosilicate (TEOS) precursor downstream of the DBD. The gaseous intermediates then condense on the surface of nanoparticles and self-reactions lead to homogeneous solid SiOx coatings, with thickness from nanometer to micrometer. This confirms the interest of post-DBD injection of the organo-silicon precursor to achieve stable production of actives species with subsequent controlled thickness of SiOx coatings. SiOx coatings of spherical and agglomerated metal and metal oxide nanoparticles (Pt, CuO, TiO2) are achieved. In the selected DBD operating conditions, the thickness of homogeneous nanometer sized coatings of spherical nanoparticles depends on the reaction duration and on the precursor concentration. For agglomerates, operating conditions can be tuned to cover preferentially the interparticle contact zones between primary particles, shifting the sintering of platinum agglomerates to much higher temperatures than the usual sintering temperature. Potential applications for enhanced thermal stability and tunable photoactivity of coated agglomerates are presented.