کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5144932 | 1379189 | 2017 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Ultrasonic treatment of glassy carbon for nanoparticle preparation
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی (عمومی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Glassy carbon particles (millimetric or micrometric sizes) dispersions in water were treated by ultrasound at 20Â kHz, either in a cylindrical reactor, or in a “Rosette” type reactor, for various time lengths ranging from 3Â h to 10Â h. Further separations sedimentation allowed obtaining few nanoparticles of glassy carbon in the supernatant (diameter <200Â nm). Thought the yield of nanoparticle increased together with the sonication time at high power, it tended to be nil after sonication in the cylindrical reactor. The sonication of glassy carbon micrometric particles in water using “Rosette” instead of cylindrical reactor, allowed preparing at highest yield (1-2Â wt%), stable suspensions of carbon nanoparticles, easily separated from the sedimented particles. Both sediment and supernatant separated by decantation of the sonicated dispersions were characterized by laser granulometry, scanning electron microscopy, X-ray microanalysis, and Raman and infrared spectroscopies. Their multiscale organization was investigated by transmission electron microscopy as a function of the sonication time. For sonication longer than 10Â h, these nanoparticles from supernatant (diameter <50Â nm) are aggregated. Their structures are more disordered than the sediment particles showing typical nanometer-sized aromatic layer arrangement of glassy carbon, with closed mesopores (diameter â¼3Â nm). Sonication time longer than 5Â h has induced not only a strong amorphization (subnanometric and disoriented aromatic layer) but also a loss of the mesoporous network nanostructure. These multi-scale organizational changes took place because of both cavitation and shocks between particles, mainly at the particle surface. The sonication in water has induced also chemical effects, leading to an increase in the oxygen content of the irradiated material together with the sonication time.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ultrasonics Sonochemistry - Volume 35, Part B, March 2017, Pages 615-622
Journal: Ultrasonics Sonochemistry - Volume 35, Part B, March 2017, Pages 615-622
نویسندگان
Jean-Marc Levêque, Laurent Duclaux, Jean-Noël Rouzaud, Laurence Reinert, Naoki Komatsu, Alexandre Desforges, Sadia Afreen, Manickam Sivakumar, Takahide Kimura,