Carbon Nanotubes Synthesis by Chemical Vapor Deposition of Methane over Zn – Fe Mixed Catalysts Supported on Alumina

نانولوله هاي كربني بوسيله ي روش نشست شيميايي فاز بخار (CVD) و كاتاليست آهن/آلومينا حاوي روي در دو دماي °C 850 و 950 و با پيش ماد ي متا به عنوان منبع كربن سنتز شد. كاتاليست با ثابت نگه داشتن مقادير آهن و تغيير ميزان روي سنتز شد. آناليزهاي پراش پرتوX و جذب-واجذب گاز نيتروژن نشان داد كه ذرات فلزي به خوبي داخل حفرات آلومينا قرار گرفته اند. نانولوله ي كربني سنتز شده بوسيله ي آناليزهاي ميكروسكوپ الكتروني روبشي (SEM)، ميكروسكوپ الكتروني عبوري (TEM)، آناليز حرارتي (TGA) و طيف بيني رامان مورد بررسي قرار گرفت. تصاوير SEM به خوبي نشان داد كه با افزايش ميزان روي در كاتاليست قطر نانولوله ها كاهش مي يابد. در طيف سنجي رامان دو نوار مربوط به نانولوله ي كربني مشاهده شد.

Carbon nanotubes were synthesized over a series of Zn-containing Fe/alumina catalysts by chemical vapor deposition method at two reaction temperatures of 850 and 950 °C using methane as a carbon source. Catalysts were synthesized by keeping Fe concentration constant and varying Zn concentration to study the effects of Zn. The catalysts were characterized using X – ray powder diffraction and N2 adsorption – desorption methods which confirmed the successful synthesis of catalysts and metals particles were inserted in alumina pores. The synthesized Carbon nanotubes were tested by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry analysis (TGA) and Raman spectroscopy. SEM images showed that the diameter of nanotubes almost was decreased with increasing Zn content of catalysts. In Raman spectroscopy, two main bands related to the carbon nanotubes were observed. Further, TGA results revealed that the percent of synthesized carbon nanotubes were almost increased with increasing [Zn]/[Fe] proportions.