The energetic transition towards renewable resources is one of the biggest challenges of this century. In this context, the role of H-2 is of paramount importance as a key source of energy that could substitute traditional fossil fuels. This technology, even if available in several manufactures, still needs to be optimized at all levels (production, storage and distribution) to be integrated on a larger scale. Among materials suitable to store H-2, Mg(BH4)(2) is particularly interesting due to its high content of H-2 in terms of gravimetric density. Nanosizing effects and role of additives in the decomposition of Mg(BH4)(2) were studied by density functional theory (DFT) modelling. Both effects were analyzed because of their contribution in promoting the decomposition of the material. In particular, to have a quantitative idea of nanosizing effects, we used thin film 2D models corresponding to different crystallographic surfaces and referred to the following reaction: Mg(BH4)(2) -> MgB2 + 4H(2). When moving from bulk to nanoscale (2D models), a remarkable decrease in the decomposition energy (10-20 kJ mol(-1)) was predicted depending on the surface and the thin film thickness considered. As regards the role of additives (Ni and Cu), we based our analysis on their effect in perturbing neighboring borohydride groups. We found a clear elongation of some B-H bonds, in particular with the NiF2 additive (about 0.1 & Aring;). We interpreted this behavior as an indicator of the propensity of borohydride towards dissociation. On the basis of this evidence, we also explored a possible reaction pathway of NiF2 and CuF2 on Mg(BH4)(2) up to H-2 release and pointed out the major catalytic effect of Ni compared to Cu.

Theoretical prediction of nanosizing effects and role of additives in the decomposition of Mg(BH4)2

Stefano Pantaleone;Elisa Albanese;Lorenzo Donà;Marta Corno;Marcello Baricco;Bartolomeo Civalleri
2024-01-01

Abstract

The energetic transition towards renewable resources is one of the biggest challenges of this century. In this context, the role of H-2 is of paramount importance as a key source of energy that could substitute traditional fossil fuels. This technology, even if available in several manufactures, still needs to be optimized at all levels (production, storage and distribution) to be integrated on a larger scale. Among materials suitable to store H-2, Mg(BH4)(2) is particularly interesting due to its high content of H-2 in terms of gravimetric density. Nanosizing effects and role of additives in the decomposition of Mg(BH4)(2) were studied by density functional theory (DFT) modelling. Both effects were analyzed because of their contribution in promoting the decomposition of the material. In particular, to have a quantitative idea of nanosizing effects, we used thin film 2D models corresponding to different crystallographic surfaces and referred to the following reaction: Mg(BH4)(2) -> MgB2 + 4H(2). When moving from bulk to nanoscale (2D models), a remarkable decrease in the decomposition energy (10-20 kJ mol(-1)) was predicted depending on the surface and the thin film thickness considered. As regards the role of additives (Ni and Cu), we based our analysis on their effect in perturbing neighboring borohydride groups. We found a clear elongation of some B-H bonds, in particular with the NiF2 additive (about 0.1 & Aring;). We interpreted this behavior as an indicator of the propensity of borohydride towards dissociation. On the basis of this evidence, we also explored a possible reaction pathway of NiF2 and CuF2 on Mg(BH4)(2) up to H-2 release and pointed out the major catalytic effect of Ni compared to Cu.
2024
14
9
6398
6409
Stefano Pantaleone; Elisa Albanese; Lorenzo Donà; Marta Corno; Marcello Baricco; Bartolomeo Civalleri
File in questo prodotto:
File Dimensione Formato  
pantaleone_civalleri_mgbh42_additives_rsc_adv_2024.pdf

Accesso aperto

Tipo di file: PDF EDITORIALE
Dimensione 1.75 MB
Formato Adobe PDF
1.75 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1966114
Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 0
  • ???jsp.display-item.citation.isi??? 0
social impact