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Kinetically Controllable Hydrogen Generation at Low Temperatures by the Alcoholysis of CaMg 2 ‐Based Materials in Tailored Solutions
Author(s) -
Ma Miaolian,
Chen Kang,
Ouyang Liuzhang,
Jiang Jun,
Liu Fen,
Shao Huaiyu,
Zhu Min
Publication year - 2020
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.202000089
Subject(s) - methanol , hydrogen , hydrogen production , chemistry , hydrolysis , yield (engineering) , chemical engineering , inorganic chemistry , materials science , organic chemistry , metallurgy , engineering
The alcoholysis of CaMg 2 ‐based materials for hydrogen generation is reported. Compared to hydrolysis in water, hydrogen supply from alcoholysis shows an excellent potential for outdoor applications, which not only bypasses the formation of passivation layers deposited on the surface of particles but also breaks the temperature bottleneck in which hydrolysis occurs over 0 °C. To remove the troublesome freezing issue of the water solution system in low‐temperature conditions, here, instead of pure methanol, methanol/water and methanol/ethanol solutions are applied to react with CaMg 2 alloy (CM 2 ) and its hydrides (H‐CM 2 ) for hydrogen generation. Compared with pure water and ethanol, the reaction of CaMg 2 ‐based materials with methanol possesses much faster reaction kinetics and gives a considerable hydrogen yield. CM 2 can generate 858 mLH2 g −1 within only 3 min at room temperature as it reacts vigorously with methanol, as opposed to a low hydrogen yield with ethanol and water (395 and 224 mLH2 g −1 within 180 min, respectively) under the same conditions. Even at −20 °C, there is still over 600 mLH2 g −1 released at a conversion rate of 70.7 % within 100 min for methanolysis, which shows its prominent advantage for hydrogen production, especially in winter or subzero areas. Interestingly, the methanolysis byproducts can transform into metal hydroxides and methanol in the reaction with water, and the methanol may be separated and reused as an intermediate. Moreover, the hydrogen behavior of CaMg 2 methanolysis can be well controlled by tailoring the components of the solutions to deliver a promising hydrogen supply system for the hydrogen economy.