Magnetic Moment Controlling Desorption Temperature in Hydrogen Storage: A Case of Zirconium-Doped Graphene as a High Capacity Hydrogen Storage Medium

Abstract

For the first time, we predict through density functional theory that a single Zr atom attached on graphene surface can adsorb maximum of 9 H2 molecules with average binding energy of 0.34 eV and average desorption temperature of 433 K leading to a wt % of 11, higher than the DoE’s requirement of 6.5 wt %.The dependency of desorption temperature (T D ) of H2 molecule with the magnetic moment (μ) of the system was exclusively studied by formulating the empirical relation T D = T 0 + aμ b (with T 0 = 399 K, a = 302.38 J–1 T K and b = 0.5). For a system with a large magnetic moment, the charge transfer to the hydrogen molecule is higher, leading to higher desorption temperature (may be higher than prescribed limit for hydrogen storage by DoE). As the magnetic moment reduces, T D comes into the desired window for fuel cell applications. It can be inferred from this study that controlling the magnetic character of the system through doping may be an effective way to bring T D in to the desired window. We qualitatively and extensively demonstrate through the analysis of the partial density of states and Bader charge transfer the interaction mechanism of Zr on graphene surface and hydrogen storage capability of Zr decorated graphene. As we have used GGA exchange correlations (LDA over binds the system), checked the stability through ab initio MD simulations, computed the diffusion barrier for avoiding metal–metal clustering, and predicted that the hydrogen wt % of the system (11 wt %) comes higher than the DoE’s requirement (6.5 wt %) with desorption temperature (433 K) and is very much suitable for fuel cell applications, we strongly believe that Zr-doped graphene can be tailored as a high capacity hydrogen storage device.

An Efficient Way To Suppress the Competition between Adsorption of H2 and Desorption of nH2–Nb Complex from Graphene Sheet: A Promising Approach to H2 Storage

“…According to Wang et al, Li-decorated porous graphene can reach a H 2 storage capacity of 10.89 wt % at T = 300 K with no external pressure. 32 wt % for zirconium-doped graphene, 1 which is much higher than the DOE target. Ao et al 33 35 Despite the high gravimetric densities reported earlier in the literature related to the positive effect of Nb in functionalizing different structures for hydrogen storage, the H 2 storage capacity on bar niobium (Nb) and niobium-functionalized graphene (GR@Nb) has not been addressed.…”

“…Liquid-state and high-pressure tanks are problematic due to the cost of liquefaction, excessive loss of hydrogen, risk of explosion at high pressure, and the great weight of high-pressure containers. Solid-state storage of hydrogen is the most promising method . In this view, the U.S. Department of Energy (DOE) has established the criteria for a sorbent to be considered for mobile application.…”

“…According to Wang et al, Li-decorated porous graphene can reach a H 2 storage capacity of 10.89 wt % at T = 300 K with no external pressure . Asha et al also predicted a gravimetric density of 11 wt % for zirconium-doped graphene, which is much higher than the DOE target. Ao et al claimed that Al-doped graphene has a high H 2 storage of 13.19 wt % with an average H 2 binding energy of −0.193 eV/H 2 .…”

“…Solid-state storage of hydrogen is the most promising method. 1 In this view, the U.S. Department of Energy (DOE) 2 has established the criteria for a sorbent to be considered for mobile application. First, it should be able to store at least 6.5 wt % in gravimetric capacity and have 70 g/L of volumetric capacity at ambient temperature (−40 to 85 °C) and moderate pressures (less than 100 atm).…”

B12-containing volleyball-like molecule for hydrogen storage

“…Compared with the hydrogen storage technologies of high pressure tank and liquid state storage, which are limited by the large size and weight of the tank and the high cost for liquefaction, the solid state storage has become a popular technology which can storage hydrogen by providing storage mediums and release it without changing the structure of mediums. A large amount of work has proved that carbon nanostructures (including carbon fullerenes, carbon nanotubes and graphyne), which decorated by the alkali metal atoms, [30][31][32][33][34] alkaline-earth metal atoms [35][36][37][38] and transition-metal atoms, [39][40][41][42][43][44] can be the promising hydrogen storage mediums. Similarly, boron nanostructures decorated by the metal atoms can also be applied in hydrogen storage.…”