Characterization of TiO2 nanoparticle's morphology and its influence on the hydrogen sorption kinetics of MgH2

Abstract

TiO2 nanorods present good performance as catalysts in the sorption behavior of magnesium hydride. In the present study, the morphology of TiO2 nanorods produced from titanate nanotubes heat-treated at 550 °C (NR550), 650 °C (NR650) and 750 °C (NR750) was characterized and their catalytic role on the sorption kinetics of MgH2 was evaluated. For this, ball-milled MgH2-TiO2 nanocomposites with 5 wt% of additives were prepared and the materials were characterized by X-ray diffraction (XRD), BET surface area and Transmission Electron Microscopy (TEM). The hydrogen sorption kinetics of the composites were evaluated in a Sievert's apparatus at 350 °C. The results indicated that NR550 and NR650 consisted of a mixture of nanorods and nanoparticles and NR750 of coarser nanoparticles of TiO2-anatase with a small amount of rutile. Composites with NR750 and NR550 presented the best sorption kinetics, suggesting the positive effect of the presence of rutile and of anatase nanorods, respectively, on the sorption properties of the material.