On the fate of the Ti catalyst during hydrogen cycling of sodium alanate

被引：87

作者：

Haiduc, AG ^{[1
]}

Stil, HA ^{[1
]}

Schwarz, MA ^{[1
]}

Paulus, P ^{[1
]}

Geerlings, JJC ^{[1
]}

机构：

[1] Shell Global Solut Int BV, Shell Res & Technol Ctr Amsterdam, NL-1030 BN Amsterdam, Netherlands

来源：

JOURNAL OF ALLOYS AND COMPOUNDS | 2005年 / 393卷 / 1-2期

关键词：

hydrogen storage; alanate; metal hydrides; x-ray diffraction;

D O I：

10.1016/j.jallcom.2004.09.061

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The state of the titanium catalyst species formed upon doping and hydrogen cycling of NaAlH4 with Ti-catalysts was studied by X-ray diffraction analysis. After doping with TiCl3, Ti is present as an hcp-Ti(Al) solid solution, while for the Ti(OBu)(4) doped system, Ti exists as an XRD-amorphous phase. Cycling of hydrogen for 1.5 times results in transformation of these initially different Ti compounds into similar compounds, whose composition is dependent on the temperature. Thus, if low temperatures were used during the cycling process (up to 175 degrees C) an amorphous Al-Ti alloy formed, while upon using high temperatures (200 degrees C and higher) Ti was present as an Al,Ti intermetallic. Correlation of the XRD and hydrogen desorption curves shows that the most active catalyst species in the present system is the amorphous Al-Ti alloy, whereas a decreased catalytic activity is found for the Al.,Ti intermetallic. (c) 2004 Elsevier B.V. All rights reserved.

引用

页码：252 / 263

页数：12

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