Catalytic mechanism of TiO2 quantum dots on the de/re-hydrogenation characteristics of magnesium hydride

In the present study, the catalyst anatase titanium dioxide (TiO2) quantum dots (QDs) of size similar to (2.50-4.00)nm was successfully synthesized by the hydrothermal method. The formation of TiO2: QDs has been established by UV-Vis spectroscopy and confirmed by transmission electron microscopy. Here, we report the catalytic action of TiO2:QDs on de/re-hydrogenation properties of magnesium hydride (MgH2/Mg). By catalyzing MgH2 through this catalyst, the onset desorption temperature of MgH2 gets reduced significantly from 360 degrees C (for ball-milled MgH2) to similar to 260 degrees C. Moreover, the Mg-TiO2: QDs sample absorbed a significant amount of hydrogen up to similar to 6.10 wt% in just 77sec at 280 degrees C. Improved rehydrogenation kinetics has been found even at lower temperatures by absorbing similar to 5.30 wt% in 74 s at 225 degrees C and similar to 5.0 wt% of hydrogen in 30 min at 100 degrees C. Based on structural,.microstructural, and XPS investigations, a feasible mechanism for improved hydrogen sorption and cyclic stability in MgH2 catalyzed with TiO2:QDs has been explained and discussed. To our knowledge, no studies have been carried out on the sorption of hydrogen in MgH2 catalyzed by TiO2:QDs. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, anatase titanium dioxide (TiO2) quantum dots (QDs) catalyst of specific size were successfully synthesized, and their catalytic effects on the hydrogen sorption properties of magnesium hydride (MgH2) were investigated. The results showed that the TiO2:QDs catalyst significantly reduced the desorption temperature of MgH2 and improved the absorption kinetics of hydrogen, leading to enhanced cyclic stability of MgH2. This research provides valuable insights into the potential application of TiO2:QDs catalyst in hydrogen storage systems.