Ni-Doped Carbon Nanotube-Mg(BH₄)₂ Composites for Hydrogen Storage

Abstract

Borohydride magnesium is widely studied as a promising hydrogen storage material due to its high gravimetric and volumetric density (14.9 wt % and 112 g/L, respectively). Different types of catalysts play a good catalytic role in enhancing the hydrogen desorption rates in borohydride systems. In the present paper, multiwalled carbon nanotubes supported Ni (Ni/ MWCNTs) were synthesized by a chemical reduction method, and the catalyst was introduced into Mg(BH 4 ) 2 to enhance the dehydrogenation kinetics. The effect of Ni/MWCNTs on the microstructural evolution and hydrogen storage properties of Mg(BH 4 ) 2 is studied. The Mg(BH 4 ) 2 -5wt% Ni/MWCNTs (95M@5NiMWCNTs) sample exhibits the best hydrogen storage performance; it starts to release hydrogen at 93 °C, which is 113 °C lower than that of the primary Mg(BH 4 ) 2 sample. Moreover, it takes only 3600 s to desorb hydrogen completely at 300 °C, showing a significant improvement on hydrogen desorption kinetics. In comparison with the primary Mg(BH 4 ) 2 sample, the dehydriding apparent activation energy of the 95M@5Ni 3 MWCNTs 2 sample is significantly lowered to 119.5 kJ mol −1 . Transmission electron microscopy analysis exhibits that the striking improvement of dehydriding properties of Mg(BH 4 ) 2 is mainly due to the synergistic catalysis of Ni and MWCNTs. This work provides a new method for designing and synthesizing high-performance catalysts in borohydride hydrogen storage materials, which is potentially utilized as a hydrogen supplier for hydrogen fuel cells.

An Overview of the Recent Advances of Additive-Improved Mg(BH4)2 for Solid-State Hydrogen Storage Material

“…There are several carbon-based materials that have been used as catalysts/additives for the Mg(BH 4 ) 2 , such as CNTs [132][133][134], carbon nanocomposites [135], two-dimensional MXene [136,137] and graphene [97,138]. The effects of CNTs on the microstructure development and H 2 storage performance of Mg(BH 4 ) 2 were investigated by Jiang et al [133].…”

Enhancement of biological hydrogen production from organic wastes with the application of nanomaterials

“…Pt has been found to be the best metal for noble metal doping, but it is an expensive noble metal. Therefore, other cheaper but efficient metals have been explored such as Ag, 52 Ni, 53 Ru, 54 Cu, 55 and Pd 56 …”

“…Pt has been found to be the best metal for noble metal doping, but it is an expensive noble metal. Therefore, other cheaper but efficient metals have been explored such as Ag, 52 Ni, 53 Ru, 54 Cu, 55 and Pd. 56 Stability of the photocatalyst plays a key role in the effective biohydrogen production from the wastewater streams.…”

Destabilization of Boron-Based Compounds for Hydrogen Storage in the Solid-State: Recent Advances

“…Ni-doped MWCNT decreased the T onset to 80 • C, with a significant reduction of the apparent activation energy to 119 kJ mol −1 compared to 451.5 kJ mol −1 for pure Mg(BH 4 ) 2 . The apparent activation energy was determined in dynamical conditions using the Kissinger method [209]. Oxides such as MoO 3 and TiO 2 allowed faster desorption kinetics with a reversible hydrogen capacity of 2.4 wt.…”