Effect of carbons (G and CFs), TM (Ni, Fe and Al) and oxides (Nb2O5 and V2O5) on hydrogen generation from ball milled Mg-based hydrolysis reaction for fuel cell

Abdel Salam Awad (1, 2) , E. El-Asmar (2) , Toufic Tayeh (1, 2) , Fabrice Mauvy (1) , Michel Nakhl (2) , Mirvat Zakhour (1) , Jean-Louis Bobet (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 LCPM - Laboratoire de Chimie Physique des Matériaux

This paper dedicated to investigation the effect of carbons (graphite and carbon fibers), transition metals (TM = Ni, Fe and Al) and oxides (Nb2O5 and V2O5) on Mg–H hydrolysis reaction in aqueous media (3.5 wt% NaCl). Mg – 10 wt% X (X = C, TM and oxides) mixtures were prepared by mechanical milling (1, 3 and 5 h). Mg – 10 wt% G mixtures show the best hydrolysis performance (95% of theoretical hydrogen generation yield in almost 3 min) in comparison to Mg – oxide and Mg – TM mixtures. In addition to the presence of micro-galvanic cells, particle size, MgH2 content, density defects, fractures and cracking have an important influence on the hydrolysis reaction. Synergetic effect of carbons and transition metals has been studied for Mg – 5 wt% G – 5 wt% Ni mixture. Activation energies were calculated using Avrami–Erofeev model. An activation energy of 14.34 kJ/mol was found for Mg/G/Ni mixture which demonstrates the best hydrolysis behavior (95% of theoretical hydrogen generation yield within 2 min). Hydrogen generated from Mg–H hydrolysis reaction was fed directly to a single Proton Exchange Membrane Fuel Cell (PEMFC). At 0.15 A, the cell voltage exhibited a stable value of approximately 0.52 V for roughly 35 min.

Mots clés: Hydrogen generation; Mg-based materials; Ball milling; Hydrolysis reaction; Synergetic effect; PEM fuel cell

Domaines: Matériaux

Abdel Salam Awad, E. El-Asmar, Toufic Tayeh, Fabrice Mauvy, Michel Nakhl, et al.. Effect of carbons (G and CFs), TM (Ni, Fe and Al) and oxides (Nb2O5 and V2O5) on hydrogen generation from ball milled Mg-based hydrolysis reaction for fuel cell. Energy, 2016, 95, pp.175-186. ⟨10.1016/j.energy.2015.12.004⟩. ⟨hal-01269779⟩