Hydrogen uptake of Ti-decorated multiwalled carbon nanotube composites

In this study, the hydrogen storage capacity of purified multiwalled carbon nanotubes (MWCNTs) was enhanced from 13- to 15-fold at a temperature of 298 K and pressure of 2.0 MPa, upon incorporation of 1.57-1.88 wt% of ultrafine Ti nanoparticles. The effect of a hydrogen spillover Ti catalyst on MWCNTs prepared using the sputtering method was investigated. A comparison between the hydrogen uptake by MWCNTs sputtered with Ti for 3000 s and that for 6000 s was also performed using the Sievert's volumetric apparatus. The significant enhancement in hydrogen uptake was attributed to the interfacial diffusion of hydrogen from Ti to the MWCNTs. The re-adsorption of hydrogen on the pristine MWCNTs and Ti-decorated MWCNTs dehydrogenated at 200 degrees C indicated that the samples did not compromise their reversible hydrogen uptake during the hydrogenation-dehydrogenation cycles. It was also found that longer exposure of Ti to the MWCNTs during sputtering improved the hydrogen storage capacity. This improvement could be attributed to the presence of a higher amount of Ti deposited on the MWCNTs, as indicated by thermogravimetric analysis study. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study found that the hydrogen storage capacity of purified MWCNTs was significantly enhanced by incorporating Ti catalyst, with longer exposure of Ti to the MWCNTs leading to further improvement in hydrogen storage capacity. The interfacial diffusion of hydrogen and the presence of a higher amount of Ti on the MWCNTs were identified as key factors contributing to the enhanced hydrogen uptake.