Ni/V-MgnHm nanoclusters: Recent advances toward improving the dehydrogenation thermodynamics for efficient hydrogen storage.

Understanding the properties of solid-state materials at the nanoscale is a crucial scientific endeavor in the pursuit of a sustainable energy future. Since magnesium hydride is the most practical material for hydrogen storage, research is still ongoing to reduce the enthalpy for dehydrogenation. In this computational theory, we systematically investigated the enthalpy of dehydrogenation of Mg n H m nanoclusters of different sizes (0.5–2.8 nm) through density functional theory (DFT) and ab-initio molecular dynamic (AIMD) simulations. Our results revealed that increasing the Mg n H m nanocluster size can remarkably improve the formation energy compared to the MgH 2 -bulk stabilization; the formation energy shifted from −65.12 kJ/mol for (0.5 nm)-Mg n H m nanocluster to −51.37 kJ/mol for (2.8 nm)-Mg n H m nanocluster. As compared to bulk phase, the lower stability of the nanoclusters indicates that it is much easier to desorb hydrogen from the surface. According to the effects of compressive/tensile strains, (2.8 nm)-Mg n H m nanocluster does not improve the dehydrogenation temperature in the desired direction. Unlike metal doping, 9.10%@Ni and 10.14%@V-doped (2.8 nm)-Mg n H m nanocluster exhibit formation energies of −47.27 and −46.34 kJ/mol with calculated desorption temperatures of 362.89 and 355.75 K, respectively, which ensures the room temperature applicability of this hydrogen storage material. [Display omitted] • The size effect of Mg n H m nanoclusters on thermodynamic properties through ab initio density functional calculations. • The compressive/tensile strains on the dehydrogenation properties of (2.8 nm)-Mg n H m are briefly reviewed. • Discovering Ni/V-doped system efficiency, reducing dehydrogenation temperature, boosting hydrogen storage performance. [ABSTRACT FROM AUTHOR]