Synthesis and Hydrogen Storage Behaviour of Pure Mg sub(2)FeH sub(6) at Nanoscale

• Published in: Materials transactions Vol. 52; no. 4; pp. 618 - 622
• Main Authors: Zhang, Xuanzhou, Tian, Wenhuai, Yang, Junzhi, Yang, Rong, Zheng, Jie, Li, Xingguo
• Format: Journal Article
• Language: English
• Published: 01-01-2011
• Subjects: Crystallites; Hydrogen storage; Mechanical milling; Nanoparticles; Nanostructure; Particle size; Scanning electron microscopy; Sintering
• ISSN: 1347-5320
• DOI: 10.2320/matertrans.MA201008

Pure Mg sub(2)FeH sub(6) compounds with two different morphologies have been successfully synthesized directly by mechanical milling (MM) and sintering of a mixture of 2Mg+Fe nanoparticles under an H sub(2) atmosphere, respectively. The successful preparation of pure Mg sub(2)FeH sub(6) can be attributed to the small particle sizes of Mg and Fe nanoparticles prepared by hydrogen plasma-metal reaction (HPMR), which provides shorter diffusion distance for hydrogen and the metals. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results show that the Mg sub(2)FeH sub(6) synthesized by mechanical milling has larger particle size but smaller crystallite size compared with the Mg sub(2)FeH sub(6) synthesized by sintering. The Mg sub(2)FeH sub(6) synthesized by mechanical milling can desorb more than 4.5 mass% hydrogen in 10 min under an initial hydrogen pressure of 0.001 bar at 573 K. Compared with the Mg sub(2)FeH sub(6) synthesized by sintering under the same conditions as the Mg sub(2)FeH sub(6) synthesized by mechanical milling, it is suggested that decrease of crystallite size is beneficial for enhancing desorption property of Mg sub(2)FeH sub(6).