Dehydrogenation Improvement of LiAlH4 Catalyzed by Fe2O3 and Co2O3 Nanoparticles

• Published in: Journal of physical chemistry. C Vol. 117; no. 36; pp. 18343 - 18352
• Main Authors: Li, Ziliang, Li, Ping, Wan, Qi, Zhai, Fuqiang, Liu, Zhiwei, Zhao, Kuifei, Wang, Ling, Lü, Shaoyuan, Zou, Liang, Qu, Xuanhui, Volinsky, Alex A
• Format: Journal Article
• Language: English
• Published: Columbus, OH American Chemical Society 12.09.2013
• Subjects: Chemistry; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; General and physical chemistry; General studies of phase transitions; General, apparatus; Materials science; Methods of crystal growth; physics of crystal growth; Nanoscale materials and structures: fabrication and characterization; Nucleation; Other topics in nanoscale materials and structures; Physics; Surface physical chemistry; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Differential scanning calorimetry; Fourier transform spectroscopy; Nucleation; Nanoparticle; Active site; Doping; Desorption; Transition metal; Nanostructure; X ray diffraction; Nanometer scale; Dehydrogenation; Growth mechanism; Kinetics; Fourier-transformed infrared spectrometry; Activation energy; Nanostructured materials; Catalyst; Dehydridation; X-ray photoelectron spectra
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp405844z

The catalytic effect of two nanoscale transition metal oxides, Fe2O3 and Co2O3, as additives on the dehydrogenation properties of LiAlH4 after milling are investigated. The onset dehydrogenation temperature for the 5 mol % Fe2O3-doped and 5 mol % Co2O3-doped samples are 85 and 79 °C lower for the first-stage and 60 and 45 °C lower for the second-stage, respectively, compared with the as-received LiAlH4. The isothermal dehydriding kinetics reveals that the 5 mol % Fe2O3-doped sample can release about 7.1 wt % hydrogen in 70 min at 120 °C, whereas as-received LiAlH4 only releases 0.3 wt % hydrogen under the same conditions. From differential scanning calorimetry (DSC) and Kissinger desorption kinetics analyses, the apparent activation energies (E a) of the 5 mol % Fe2O3-doped sample are 54.2 and 86.4 kJ/mol for the first two dehydrogenation stages, resulting in decreases of 42.8 and 50% compared with those of as-received LiAlH4, respectively, which are considerably lowered compared with LiAlH4 doped with other reported catalysts calculated by Kissinger method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) analyses demonstrate that these finely dispersed Li2Fe2.4O4.6, Fe0.957O, and various Co oxides contribute to kinetics improvement by serving as active sites for nucleation and growth of dehydrogenated products.