Nanohybrid of titania/carbon nanotubes – nanohorns: A promising photocatalyst for enhanced hydrogen production under solar irradiation

Nanohybrid of titania/carbon nanotubes – nanohorns: A promising photocatalyst for enhanced hydrogen production under solar irradiation

Type	Journal Article
Author	M. MamathaKumari
Author	D. Praveen Kumar
URL	http://www.sciencedirect.com/science/article/pii/S0360319914032510
Volume	40
Issue	4
Pages	1665-1674
Publication	International Journal of Hydrogen Energy
Date	January 30, 2015
Abstract	Authors describe the unique beneficial photocatalytic properties of carbon nanotubes and nanohorn mixtures in nanohybrid photocatalysts, for enhanced H2 production. Researchers fabricated mixtures of straight and defect-free multiwalled carbon nanotubes (MWCNTs), single walled carbon nanohorns (SWCNHs), and multiwalled carbon nanohorns (MWCNHs) using the arc discharge method. They obtained Functionalized Carbon Nanotubes (FCNTs) composed of MWCNTs, MWCNHS and SWCNHs using acid functionalization process. They obtained TiO2/FCNTs (CTP) nanohybrid photocatalysts with varying amounts of FCNTs, via the wet impregnation method. They examined the photocatalytic activity of both pristine TiO2 as well as the nanohybrids in aqueous glycerol solution under solar irradiation. Reaction parameters such as amount of catalyst and amount of FCNTs in nanohybrids were optimized to ensure high rates of H2 production. With a relatively low amount of pristine TiO2, a high rate of H2 production of 2134 μmol h−1 gcat−1 was obtained. This is probably due to such factors as well dispersed catalyst, reduced particle–particle agglomeration, resulting in enhanced light absorption, improved separation of charge carriers and utilization for red-ox reactions. Better results were obtained with the use of nanohybrid catalysts. The enhanced photocatalytic activities of the nanohybrid catalysts are ascribed to the synergetic effects of FCNTs that minimize light reflection which promotes enhanced solar light sensitization, good dispersion of the catalysts in the reaction solution, and improved surface-interface reactions of photogenerated charge carriers. In the present study 10 wt% FCNTs in nanohybrid (CTP-10) exhibited superior photocatalytic activity for H2 generation, nearly 3 times higher than that of pristine TiO2 catalyst.