Catalytic action of Y2O3@graphene nanocomposites on the hydrogen-storage properties of Mg–Al alloys. Issue 29 (12th July 2017)

• Record Type: Journal Article
• Authors: Lan, Zhiqiang; Sun, Zhenzhen; Ding, Yuchuan; Ning, Hua; Wei, Wenlou; Guo, Jin
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 29(2017)
• Page Start: 15200
• Page End: 15207
• Publication Date: 2017-07-12
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7ta03879h
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : The synthetic effect of Y2 O3 and rGO has a significant improvement on the thermodynamic and kinetic properties of Mg–Al alloys. Abstract : An Y2 O3 @rGO nanocomposite was synthesized via an impregnation method and the catalytic effect of the nanocomposite on the hydrogen-storage properties of a Mg–Al alloy was investigated. The pressure composition isotherm measurement results revealed that the Mg–Al–Y2 O3 @rGO composite underwent a reversible hydrogenation/dehydrogenation process at 250 °C. Furthermore, the onset temperatures of hydrogenation and dehydrogenation were significantly ( i.e., 102 °C and 122 °C, respectively) lower than the respective values corresponding to the Mg–Al alloy. The Y2 O3 @rGO nanocomposite enhanced the hydriding kinetic properties of the alloy. The hydrogenation kinetic parameter of the Mg–Al alloy increased from 0.008 to 0.195 at 300 °C with 5 wt% of the Y2 O3 @rGO composite. The values of 162.6 kJ mol −1 H2 and 145.9 kJ mol −1 H2 were obtained for the dehydrogenation energy barrier (evaluated by means of a Kissinger plot) of the Mg–Al alloy and the Mg–Al–Y2 O3 @rGO hydride, respectively. The reaction enthalpy of hydrogenation/dehydrogenation (determined from a van't Hoff plot) of the alloy decreased with the addition of the Y2 O3 @rGO nanocomposite. For example, the values of 70.7 kJ mol −1 H2 and 54.3 kJ mol −1 H2 were obtained for the reaction enthalpy of hydrogenation associated with the Mg–Al alloy and the Mg–Al–Y2 O3 @rGO composite, respectively. Therefore, the addition of the Y2 O3 @rGO nanocomposite is conducive for improving the thermodynamic and kinetic properties of hydrogenation/dehydrogenation of the Mg–Al alloy.