Faculty Publications
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Item Large scale synthesis of carbon nanofibres on sodium chloride support(InTech Europe info@sagepub.co.uk, 2012) Rajarao, R.; Badekai Ramachandra, B.R.Large scale synthesis of carbon nanofibres (CNFs) on a sodium chloride support has been achieved. CNFs have been synthesized using metal oxalate (Ni, Co and Fe) as catalyst precursors at 680 °C by chemical vapour deposition method. Upon pyrolysis, this catalyst precursors yield catalyst nanoparticles directly. The sodium chloride was used as a catalyst support, it was chosen because of its non-toxic and water soluble nature. Problems, such as the detrimental effect of CNFs, the detrimental effects on the environment and even cost, have been avoided by using a water soluble support. The structure of products was characterized by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The purity of the grown products and purified products were determined by the thermal analysis and X-ray diffraction method. Here we report the 7600, 7000 and 6500 wt% yield of CNFs synthesized over nickel, cobalt and iron oxalate. The long, curved and worm shaped CNFs were obtained on Ni, Co and Fe catalysts respectively. The lengthy process of calcination and reduction for the preparation of catalysts is avoided in this method. This synthesis route is simple and economical, hence, it can be used for CNF synthesis in industries. © 2012 Rajarao and Bhat.Item Green approach to synthesize multi-walled carbon nanotubes by using metal formate as catalyst precursors(2013) Rajarao, R.; Badekai Ramachandra, B.The multi-walled nanotubes (MWNTs) have been synthesized in large scale by using metal formate as catalyst precursors. The calcium carbonate is used as catalyst support, it is chosen because of its non toxic and easily soluble nature. The synthesis was carried out by chemical vapor deposition method for 15 min under optimized conditions. The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and X-ray diffraction (XRD) method. The purity of the as grown products and purified products were determined by thermal analysis. The obtained yield of MWNTs was about 8300 wt% relative to the nickel catalyst. This synthesis route avoids the lengthy process of calcination and reduction for the preparation of catalysts hence this method is more economical. This economical and environmental friendly synthesis route can be used for synthesizing MWNTs in large scale. Copyright © 2013 American Scientific Publishers All rights reserved.Item Activated carbon derived from non-metallic printed circuit board waste for supercapacitor application(Elsevier Ltd, 2016) Rajagopal, R.R.; Aravinda, L.S.; Rajarao, R.; Badekai Ramachandra, B.R.; Sahajwalla, V.Activated carbons (ACs) have been synthesized by using waste PCBs via physical activation subsequent to pyrolysis processes. The physical and chemical properties of the produced activated carbons were studied using nitrogen adsorption, FT-IR spectroscopy, RAMAN spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy techniques. Among the synthesized ACs, AC with the highest surface area of 700 m2 g-1 produced at 850 °C for a time interval of 5 h was subjected to electrochemical studies. Capacitance behaviour of the obtained AC sample has been evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GC-D) measurements and electrochemical impedance spectroscopy (EIS) technique. Specific capacitance (Cspec) values vary from 220, 185 and 156 F g-1 for corresponding scan rate of 30, 50 and 100 mV s-1 respectively. The well-developed surface area properties and good capacitance values associated with nitrogen functionalities indicates the AC developed is a good and suitable candidate for the supercapacitor fabrication. © 2016 Elsevier Ltd.