@article{Zhang2015, 
author = {Xin Zhang and Yongfeng Liu and Ke Wang and Mingxia Gao and Hongge Pan},
title = {Remarkably improved hydrogen storage properties of nanocrystalline TiO2-modified NaAlH4 and evolution of Ti-containing species during dehydrogenation/hydrogenation},
year = {2015},
journal = {Nano Research},
volume = {8},
number = {2},
pages = {533-545},
keywords = {hydrogen storage, complex hydrides, catalyst addition, nanocrystalline TiO2@C},
url = {https://www.sciopen.com/article/10.1007/s12274-014-0667-9},
doi = {10.1007/s12274-014-0667-9},
abstract = {Adding a small amount of nanocrystalline TiO2@C (TiO2 supported on nanoporous carbon) composite dramatically decreases the operating temperatures and improves the reaction kinetics for hydrogen storage in NaAlH4. The nanocrystalline TiO2@C composite synthesized at 900 ℃ (referred as TiO2@C-900) exhibits superior catalytic activity to other catalyst-containing samples. The onset dehydrogenation temperature of the TiO2@C-900-containing sample is lowered to 90 ℃; this is 65 ℃ lower than that of the pristine sample. The dehydrogenated sample is completely hydrogenated at 115 ℃ and 100 bar of hydrogen pressure with a hydrogen capacity of 4.5 wt.%. Structural analyses reveal that the Ti undergoes a reduction process of Ti4+→Ti3+→Ti2+→Ti during the ball milling and heating processes, and further converts to Ti hydrides or forms Ti-Al species after rehydrogenation. The catalytic activities of Ti-based catalytic species decrease in the order Al-Ti-species > TiH0.71 > TiH2 > TiO2. This understanding guides further improvement in hydrogen storage properties of metal alanates using nanocrystalline transition metal-based additives.}
}