Browsing by Author "Liao, Chi-Wei"

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Facilitated hydrogen release kinetics from amine borane functionalization on gate-opening metal-organic framework
(2018-09-25)
Liao, Chi-Wei
;
Tseng, Po-Sen
;
Chang, Bor Kae
;
Wang, Cheng-Yu
;
材料科學與工程學系
For the first time, we functionalized the gate-opening metal-organic framework (GO-MOF) of MIL-53(Al) with ammonia borane (AB, NH3BH3) via post-synthesis method. In this report, unusual structural breathing and dehydrogenation behaviors of AB doped MOF (MIL-53-AB) were discovered. Surface coating triggered the GO-MOF breathing phenomenon and opened the structure, and gate was closed after dehydrogenation. The dehydrogenation peak temperature was greatly reduced by 30 degrees C compared to that of pristine AB with suppressed byproduct like ammonia. The MOFs with surface coated AB exhibited remarkably fast hydrogen generation rate and corresponding low apparent activation energy, estimated at < 40 kJ/mol, which is much lower than that of crystalline AB, and even comparable to AB hydrolysis with catalysts. The ammonia borane functionalized MIL-53 has shown greatly improved dehydrogenation from solid phase of AB.
Influence of Metal-Organic Framework Porosity on Hydrogen Generation from Nanoconfined Ammonia Borane
(2017-12-14)
Chung, Jing-Yang
;
Liao, Chi-Wei
;
Chang, Yi-Wei
;
Chang, Bor Kae
;
Wang, Hao
Hydrogen released from chemical hydride ammonia borane (AB, NH3BH3) can be greatly improved when AB is confined in metal-organic frameworks (MOFs), showing reduced decomposition temperature and suppressed unwanted byproducts. However, it is still debatable whether the mechanism of improved AB dehydrogenation is due to catalysis or nanosize. In this research, selected MOF (IRMOF-1, IRMOF-10, UiO-66, UiO-67, and MIL-53(Al)) were chosen to explore both catalytic effect of the metal clusters and the manipulation of pore size for nanoconfinement by variations in ligand length. When AB particle size was restricted by the controlled micropores of MOFs, we observed that the decomposition temperature was not correlated to the MOF catalytic environment, but inversely proportional to the reciprocal of the particle size. The results correspond well with the derived thermodynamic model for AB decomposition considering surface tension of nanoparticles.