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Generation of hydrogen upon immersion of Mg in Mn(Ac) 2 and the reaction mechanism
Author(s) -
Xu Tingting,
Wang Ning,
Chai Yujun
Publication year - 2020
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.6066
Subject(s) - hydrogen , hydrogen production , permeation , oxide , chemistry , inorganic chemistry , metal , galvanic cell , ion , membrane , organic chemistry , biochemistry
Summary Reactions between metals and H 2 O could provide high‐purity hydrogen gas for portable fuel cell. However, the initial reaction is typically hindered due to the existence of a dense outer oxide film. Herein, rapid generation of hydrogen following immersion of Mg in a solution of Mn(Ac) 2 is examined. The formation of an Mg/Mn galvanic cell results in the destruction of an oxide film, inducing a continuous reaction between Mg, Mn, and water. Moreover, Mn is then oxidized back to Mn 2+ , illustrating that the metal further participates in the generation of hydrogen. The detected reaction rate varies from 37.5 to 55 mL g −1 minute −1 , and the hydrogen volume is ~1000 mL at 35°C. Furthermore, the in‐situ potential changes with the generation of hydrogen, reflecting the fluctuation of the Mg 2+ and OH − ions. Notably, the formation of flake‐type Mn or Mn(OH) 2 facilitates the permeation of water, OH − ions, and the overflow of hydrogen. Conversely, the accumulation of square‐type Mg(OH) 2 hinders permeation, lowering the hydrogen generation rate. The results of the present study provide new insights into the design of highly pure hydrogen generation systems by adjusting the solution composition.