Enhanced Hydrogen Generation Properties of MgH2-Based Hydrides by Breaking the Magnesium HydroxidePassivation Layer

Energies

Lixian Sun¹  Liuzhang Ouyang²  Hui Wang²  Min Zhu²  Minghong Huang²  Ruoming Duan²  Miaolian Ma² 

[1] Guangxi Collaborative Innovation Center of Structure and Property for New Energy and Materials, Guilin 541004, China;School of Materials Science and Engineering and Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641, China;

关键词: MgH2-based hydride;    hydrolysis;    hydrogen generation;    composites;   

DOI  :  10.3390/en8054237

来源: DOAJ

【 摘 要 】

Due to its relatively low cost, high hydrogen yield, and environmentally friendly hydrolysis byproducts, magnesium hydride (MgH2) appears to be an attractive candidate for hydrogen generation. However, the hydrolysis reaction of MgH2 is rapidly inhibited by the formation of a magnesium hydroxide passivation layer. To improve the hydrolysis properties of MgH2-based hydrides we investigated three different approaches: ball milling, synthesis of MgH2-based composites, and tuning of the solution composition. We demonstrate that the formation of a composite system, such as the MgH2/LaH3 composite, through ball milling and in situ synthesis, can improve the hydrolysis properties of MgH2 in pure water. Furthermore, the addition of Ni to the MgH2/LaH3 composite resulted in the synthesis of LaH3/MgH2/Ni composites. The LaH3/MgH2/Ni composites exhibited a higher hydrolysis rate—120 mL/(g·min) of H2 in the first 5 min—than the MgH2/LaH3 composite— 95 mL/(g·min)—without the formation of the magnesium hydroxide passivation layer. Moreover, the yield rate was controlled by manipulation of the particle size via ball milling. The hydrolysis of MgH2 was also improved by optimizing the solution. The MgH2 produced 1711.2 mL/g of H2 in 10 min at 298 K in the 27.1% ammonium chloride solution, and the hydrolytic conversion rate reached the value of 99.5%.

【 授权许可】

Unknown