Catalytic effect of TiF3 on hydrogenation and dehydrogenation of Mg-based hydrogen storage alloy prepared by milling

Abstract

Transition metals or their derivatives are effective catalysts for enhancing the properties of Mg-based hydrogen storage materials. This study focuses on the Ce₅Mg₈₅Ni₁₀+x wt.%TiF₃ (x = 0–7) (Ce₅Mg₈₅Ni₁₀+xTiF₃ (x = 0–7)) composites fabricated by mechanical milling. Moreover, the additive TiF₃ can decrease the initial dehydrogenation temperature of MgH₂ and slightly ameliorate the thermodynamic property. Specifically, the alloy with 5 wt% TiF₃ exhibits the optimal activation performance and kinetics properties which can absorb 4 wt% hydrogen in 24 s at 473 K and desorb 3 wt% hydrogen in 168 s at 573 K. Because of its lowest apparent activation energy for hydrogen desorption (55.87 kJ/mol). Furthermore, the onset dehydrogenation temperature of the alloy with 5 wt% TiF₃ is about 530.4 K, which is believed to be associated with a decline in the thermal stability of magnesium hydride caused by the addition of TiF₃.