Reversible storage of hydrogen in NaF–MB2 (M = Mg, Al) composites

Abstract

In this work, two new systems, 2NaF + MgB₂ + 0.05TiF₃ (Mg system) and 2NaF + AlB₂ + 0.05TiF₃ (Al system), are proposed for reversible hydrogen storage. It was found that NaBH₄ can be reversibly formed in these two systems. Compared to pure NaBH₄, a significant kinetic and thermodynamic destabilization with respect to the hydrogenation and dehydrogenation is achieved. The reversible hydrogen storage capacity is up to 3.8 and 2.5 wt% for the Mg and Al systems, respectively. Both systems revealed particularly good hydrogen storage reversibility. Furthermore, the hydrogenation and dehydrogenation mechanisms for these two systems are described based on the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses.