Premium
Hydrogen Generation by Hydrolysis of an Al/Al 2 O 3 ‐Composite Powder After Heat Treatment
Author(s) -
Huang Xiani,
Chen Zhi,
Gao Tong,
Huang Qiaoli,
Niu Feng,
Qin Laishun,
Huang Yuexiang
Publication year - 2013
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201300129
Subject(s) - hydrolysis , reactivity (psychology) , agglomerate , oxide , materials science , hydrogen , chemical engineering , composite number , x ray photoelectron spectroscopy , layer (electronics) , coating , inorganic chemistry , chemistry , metallurgy , composite material , organic chemistry , medicine , alternative medicine , pathology , engineering
Hydrogen generation by reaction of aluminum (Al) with water is generally hindered by the presence of the dense oxide layer on its surface. Eliminating or activating the passive oxide layer is a key step for improving the hydrolysis reactivity of aluminum to generate hydrogen. In the present investigation, a gel‐coating method was used to prepare the precursor powder of a composite with alumina (Al/Al 2 O 3 ) to clarify the effect of the Al 2 O 3 additive on the hydrolysis of Al powder. The results showed that γ‐Al 2 O 3 was formed after the heat treatment of the Al/Al 2 O 3 composite precursor at 550 °C for 4 h, which results in the coating of Al particles with γ‐Al 2 O 3 agglomerates. The XPS analysis of the heat‐treated Al particles indicated that the initial dense oxide layer covered on the surface of Al particles transformed into a loose γ‐Al 2 O 3 layer that increased the hydrolysis reactivity of the Al powder. The Al 2 O 3 additive coated on the surface of the Al particles was found to lower the hydrolysis reactivity of the Al particles. It was concluded that the heat treatment rather than the addition of the γ‐Al 2 O 3 additive is the predominant factor in determining the hydrolysis reactivity of the Al particles. However, it was observed that coating the Al particles with Al 2 O 3 did hinder the degradation of the Al hydrolysis reactivity upon exposure in air for several days.