Catalytic mechanism of TiO2 quantum dots on the de/re-hydrogenation characteristics of magnesium hydride
Catalytic mechanism of TiO2 quantum dots on the de/re-hydrogenation characteristics of magnesium hydride
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DOI：
10.1016/j.ijhydene.2021.09.006
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发表时间：
2021-10
影响因子：
7.2
通讯作者：
S. K. Pandey;A. Bhatnagar;V. Shukla;Rashmi Kesarwani;Uday Deshpandey;T. Yadav
中科院分区：
文献类型：
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作者：
S. K. Pandey;A. Bhatnagar;V. Shukla;Rashmi Kesarwani;Uday Deshpandey;T. Yadav
本文采用水热法制备了尺寸为~ (2.50 ~ 4.00)nm的锐钛矿型二氧化钛（TiO2）量子点（QDs）。通过紫外可见光谱和透射电镜证实了TiO2：量子点的形成。本文报道了TiO2：量子点对氢氧化镁（MgH2/Mg）脱氢/再氢化性能的催化作用。通过该催化剂催化MgH2， MgH2的开始解吸温度从~ 360°C（对于球磨MgH2）显著降低到~ 260°C。此外，Mg-TiO2: QDs样品在280°C下仅需77秒即可吸收大量的氢，高达6.10 wt%。即使在较低的温度下也能改善再加氢动力学，在225°C下74 s内吸收~ 5.30 wt%的氢，在100°C下30分钟吸收~ 5.0 wt%的氢。基于结构，。显微结构和XPS研究表明，TiO2:QDs催化mgh2提高氢吸附和循环稳定性的可行机制得到了解释和讨论。据我们所知，目前还没有关于TiO2:QDs催化mgh2吸附氢的研究。
In the present study, the catalyst anatase titanium dioxide (TiO2) quantum dots (QDs) of size ∼ (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 MgH2through this catalyst, the onset desorption temperature of MgH2gets reduced significantly from ∼360 °C (for ball-milled MgH2) to ∼260 °C. Moreover, the Mg-TiO2: QDs sample absorbed a significant amount of hydrogen up to ∼6.10 wt% in just 77sec at 280 °C. Improved rehydrogenation kinetics has been found even at lower temperatures by absorbing ∼5.30 wt% in 74 s at 225 °C and ∼5.0 wt% of hydrogen in 30 min at 100 °C. Based on structural,.microstructural, and XPS investigations, a feasible mechanism for improved hydrogen sorption and cyclic stability in MgH2catalyzed with TiO2:QDs has been explained and discussed. To our knowledge, no studies have been carried out on the sorption of hydrogen in MgH2catalyzed by TiO2:QDs.