The Effect of Graphite and Fe2O3 Addition on Hydrolysis Kinetics of Mg-Based Hydrogen Storage Materials

Abstract

In this paper, graphite and Fe2O3 are introduced into MgH2 powder by the method of hydrogenation after magnetic grinding. Hydrogen storage materials which composite of MgH2–5 wt.% C and MgH2–5 wt.% C–5 wt.% Fe2O3 are successfully prepared. The physical structure of these materials was analyzed and characterized by XRD, SEM, etc. Furthermore, the influence of graphite and Fe2O3 on the hydrolysis of MgH2 was systematically investigated. The results show that MgH2–C–Fe2O3 composite powder has the fastest hydrogen release rate in municipal drinking water and the highest conversion rate. Graphite and Fe2O3 can effectively reduce the activation energy of the hydrolysis reaction of MgH2 and improve the hydrolysis kinetics of MgH2. The synergistic effect of the coaddition of graphite and Fe2O3 can significantly increase the hydrolysis conversion rate of MgH2 and improve the hydrolysis kinetics.

Effect of LiH on the fast hydrolysis and hydrogen generation of MgH2 by ball milling

“…, NaBH 4 , MgBH 4 , LiBH 4 ), 11–13 light weight metals ( i.e. , Mg and Al) 14,15 and metal hydride ( i.e. , MgH 2 and CaH 2 ) 16,17 have been studied.…”

Hydrolysis Kinetics of LiAlH4 at Subzero Temperatures

“…Hydrogen, a clean carbon-free energy carrier with high heating value, could be helpful to solve the current energy shortage and environmental pollution problems. − Hydrogen storage materials are promising hydrogen suppliers for stationary, portable, and transport vehicles to simplify long-distance transportation. − The operating ambient temperature plus full solar load was set by the US Department of Energy (DOE) for on-board hydrogen storage systems for light-duty vehicles to be −40 to 60 °C as the ultimate goal to realize commercially effective applications . The hydrolysis of hydrogen storage materials is a feasible path to meet the temperature target since it is an exothermic reaction, and no additional heating is needed. − The hydrolysis of NaBH 4 , , MgH 2 , ,, Al, − and LiAlH 4 − has been widely studied and significantly promoted at room temperature. However, the study on hydrogen release reactions at subzero temperatures is hindered due to its complexity, including the development of an optimized anti-icing aqueous solution and improvement of reaction kinetics as well as conversion rate …”

Light-activated hydrolysis properties of Mg-based materials

“…Various strategies, such as the acidification of the reaction environment, 5,6 the use of salt solutions, 5,7 the modification of the morphology to obtain nanostructured hydrolysable materials, 8,9 and the incorporation of additives with different functions, 10,11 have been adopted and verified effective for activating the reaction of MgH 2 with water. However, these strategies still face many challenges, such as complex operation, high-cost or the pollution of additives.…”