CATALYTICALLY ENCHANCED SYSTEMS FOR HYDROGEN STORAGE

Jensen, Craig M.

University of Hawaii

关键词: Hydrogen, Storage, Metal Hydrides, Naalh4, Sodium Aluminum Hydride, Catalysts;    Aluminium;    Neutron Diffraction;    Electron Spin Resonance;    08 Hydrogen;   

DOI  :  10.2172/890543
RP-ID  :  Final Report
RP-ID  :  FC36-00GO10537
RP-ID  :  890543

美国|英语

来源: UNT Digital Library

【 摘 要 】

Previous U.S. DOE sponsored research at the University of Hawaii resulted in the development of methods of doping of sodium aluminum hydride, NaAlH4 with titanium, zirconium and other catalysts such that: dehydriding occurs at temperatures as low as 100°C; rehydriding requires less than 1 h; and >4 weight percent hydrogen can be repeatedly cycled through dehydriding/rehydriding. These materials appeared to be on the threshold of practical viability as hydrogen carriers for onboard fuel cells. However, it was apparent that further kinetic enhancement was required to achieve commercial viability. Thus, one of the primary goals of this project was to develop the requisite improved catalysts. Over the course of this project, a variety of titanium and zirconium dopant precursors were investigated. Moreover, the approach was to conduct guided search for improved catalysts by obtaining a fundamental understanding of the chemical nature of the titanium dopants and their mechanism of action. Therefore, the projected also aimed to determined the chemical nature of the titanium species that are formed upon mechanical milling of NaAlH4 with the dopant precursors through synchrotron X-ray and neutron diffraction as well as transmission electron microscopy, scanning electron microscopy, and electron paramagnetic resonance (EPR) spectroscopy. In addition to kinetic studies, insight into the mechanism of action of the dopants was gained through studies of the destabilization of hydrogen in NaAlH4 by the dopants through infrared, NMR, and anelastic spectroscopy.