Dual-tuning thermodynamics/kinetics properties and hydrogen
generation of magnesium-base composites
Liuzhang Ouyang*, Hui Wang, Jiangwen Liu, Min Zhu
Key Laboratory of Advanced Energy Storage Materials of Guangdong Province,
China-Australia Joint Laboratory for Energy & Environmental Materials,
School of Materials Science and Engineering, South China University of
Technology,Guangzhou, 510641, P.R. China
E-mail of the corresponding author: meouyang@scut.edu.cn
As a type of potential high-capacity hydrogen storage materials, Mg and Mg-based
composites have attained sustaining research interest over last two decades. Herein we
demonstrate our latest effort in dual-tuning the thermodynamics/kinetics properties and
hydrogen genertaion of magnesium-base composites[1].
Based on previous successful preparation of Mg(In) binary solid solution alloy for
reversible hydrogen storage[2], ternary and quarternary Mg-In-Y[3], Mg-In-Al, and Mg-InAl-Ti composites are further explored, the hydriding reaction mechanism and hydrogen
storage properties are systematically investigated. It is found Mg-In-Y, Mg-In-Al, and
Mg-In-Al-Ti composites show improved thermodynamic properties and full de/hydriding reversibility, but with different reaction mechanism. In addition, a plasmaassisted ball milling is used to prepare in-situ formed MgF2 catalyzed Mg-In[4] and MgIn-Al-Ti composite and Mg2In0.1Ni solid solution, both of which show great improvement
in not only thermodynamics but also kinetics.
Compared to MgH2 + REH3 (where RE denotes misch metal, such as La, Ce, Pr and
Nd) composites, MgH2 + MmH3 composites displayed the fastest hydrolysis rate due to
mutual catalysis of LaH3, CeH3, PrH3, and Nd2H5. Hydrolysis of the MgH2 + MmH3
composites produced 695 mL g-1 hydrogen in 5 min, 828 mL g-1 hydrogen in 15 min, and
the highest hydrogen yield reached 9.79 wt.% at 298 K.The hydrolysis mechanisms of
MgH2 + REH3 composites are also discussed herein. Nickel has shown to be a good
catalyst for improving the hydrolysis performances of MgH2 + REH3 composites through
investigating their hydrolysis kinetics and mechanisms. A material with superior
hydrolysis performance, namely MgH2 + MmH3 + Ni composites has been identified,
which can generate 276 mL g-1 min-1 hydrogen in the first 1.5 min and achieve a total
yield of 1088 mL g-1 [5]. Ni served to modify the hydrolysis mechanisms of MgH2 +
REH3 composites to improve their hydrolysis properties. Moreover, Ni has been found to
promote the direct hydrolysis of CeH3 to CeO2 to liberate more hydrogen and to render
the stable Nd2H5 reactive towards water.
ACKNOWLEDGMENTS
This work was financially supported by the Ministry of Science and Technology of China
(No. 2010CB631302), the NSFC (Nos. U1201241 and 51271078).
References
[1] L. Z. Ouyang, X. S. Yang, M. Zhu, et al, J. Phys. Chem. C, 118(2014)7808
[2] H. C. Zhong, M. Zhu, H. Wang, et al, Scripta Mater. 65 (2011) 285
[3] F.P. Luo, H. Wang, L.Z. Ouyang, et al, Int J Hydrogen Energ, 38(2013): 10912
[4] L. Z. Ouyang, Z. J. Cao, H. Wang, et al, J. Alloys Compd., 586 (2014) 113
[5] J. M. Huang, L. Z. Ouyang, Y. J. Wen, et al, Int J Hydrogen Energ, 39 (2014) 6814