Showing papers by "Prathap Haridoss published in 2017"

Benefits of tubular morphologies on electron transfer properties in CNT/TiNT nanohybrid photocatalyst for enhanced H2 production

Abstract: In order to study the influence of one dimensional tubular structures for effective electron and hole transportation onto the surface of a photocatalyst leading to efficient solar photocatalytic hydrogen production, functionalized carbon nanotube (FCNT)/TiO2 nanotube nanohybrids were prepared. TiO2 nanotubes (TiNTs) were prepared by hydrothermal method. A series of novel functionalized carbon nanotube/TiO2 nanotube nanohybrids (CTT) were prepared for different wt% (1–20) of FCNTs by wet impregnation method to extend absorption in the visible region and also to retard the electron–hole pair recombination and thereby to enhance the H2 production capability under solar light irradiation. The functionalized carbon nanotube/TiO2 nanotube nanohybrids (CTT) were characterized with XRD, TEM, DRS-UV-Vis, Raman spectroscopy and XPS for crystal structure, morphology, optical properties and chemical composition. Addition of FCNTs to the TiNTs in CTT nanohybrids extended the absorption to the visible region. Relative electron–hole recombination times were measured with photoluminescence spectra. The highest H2 generation of 29 904 μmol g−1 was observed after 4 h under optimal conditions due to better separation of electron–hole pairs and electron conducting properties.

Homogenization for Dispersion and Reduction in Length of Carbon Nanotubes

Abstract: An important aspect that limits the use of carbon nanotubes (CNTs) is the difficulty in obtaining homogeneously dispersed CNTs of uniform length. Hence, homogenization of multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) was carried out using bullet blender and the dispersion behavior was compared with that of ultrasonication. 1% sodium dodecyl sulphate (SDS), Triton-x-100 and polyethylene glycol 4000 were used as dispersing agents during homogenization. The dispersed CNTs were studied using transmission electron microscopy, ImageJ and Raman spectroscopy. Though dispersion and reduction in length of MWCNTs were observed both with ultrasonication and homogenization, lowest length range with about 75% reduction in polydispersity index was obtained on homogenization. Longer time of ultrasonication resulted in damage to small MWCNTs. Well dispersed and shorter MWCNTs were obtained with Triton-x-100 while reduction in length was minimum with SDS. SWCNTs of less than 1 μm length could be obtained by homogenization with Triton-x-100.

Synthesis of graphene sheets from single walled carbon nanohorns: novel conversion from cone to sheet morphology

Abstract: Graphene sheets have been synthesized from single walled carbon nanohorns by one-step reaction with hydrogen peroxide. The obtained graphene sheets are in pure form and shows good electrical properties. As-synthesized graphene acts as dual function of support as well as reducing agent to prepare graphene-silver nanoparticle composite having uniform particle size of 6 nm. This method can easily be scalable to prepare graphene or graphene supported metal nanoparticle composites for versatile applications.