Spontaneous dynamical disordering of borophenes in MgB2 and related metal borides

Li, Sichi; Gunda, Harini; Ray, Keith G.; Wong, C. S.; Xiao, Penghao; Friddle, Raymond W.; Liu, Yi‐Sheng; Kang, ShinYoung; Dun, Chaochao; Sugar, Joshua D.; Kolasinski, Robert; Wan, Liwen F.; Baker, Alexander A.; Lee, Jonathan R. I.; Urban, Jeffrey J.; Jasuja, Kabeer; Allendorf, Mark D.; Stavila, Vitalie; Wood, Brandon C.

doi:10.1038/s41467-021-26512-4

Cited by 22 publications

(22 citation statements)

References 65 publications

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“…As a result, there is an enthalpic driving force toward clustering to passivate bonds. Analogously, another recent study showed that complex boron clustering is energetically favorable on the B-terminated (001) surface and kinetically accessible at room temperature due to the unpassivated nature of the boron surface bonds . However, it is worth noting that bonds are also undercoordinated at the Mg-rich edge, which is not prone to polyboron formation.…”

Section: Resultsmentioning

confidence: 80%

“…Simultaneously, there are more B–B 4–7 arrangements, and these B atoms are more likely to be neutral as opposed to negatively charged. The change in charge reflects rearrangements of several B atoms to form clusters that have more elemental B character . Further signatures of polyboron clustering include the formation of units featuring B atoms multiply coordinated to other B atoms as well as H. These B atoms are also more generally neutral as opposed to the more common positive charge immediately following initialization.…”

Section: Resultsmentioning

confidence: 99%

“…A follow-up study showed that H 2 bond breaking is not rate limiting for hydrogenation, nor is the process of hydrogen surface diffusion, narrowing the focus for hydrogenation rate enhancement to the later hydrogenation steps of B–H bond formation, B–B bond cleavage, and the separation of B x H y units from the MgB 2 hexagonal boron ring network. The stability of that boron network was elucidated in recent work by Li et al, which revealed that boron-terminated basal surfaces are natively unstable to disordering, suggesting the possibility of additional hydrogen-prone defective sites on surfaces . These studies further emphasize the need to understand the chemical process of hydrogen attack and incremental B–H coordination to form B x H y complexes at highly defective sites and interfaces.…”

Section: Introductionmentioning

confidence: 89%

“…While the Mg-terminated (0001) basal plane is the lowest-energy surface (0.82 J/m 2 ), 25 MgB 2 crystallites cannot be entirely comprised of (0001) surfaces due to geometric considerations. Furthermore, further disordering 24 or erosion of basal planes will eventually result in hydrogen penetration and the formation of terraces that expose oblique surfaces and edges. The next-lowest-energy surface is the Mg-terminated (101̅ 0) surface (1.32 J/m 2 ), 25 while the B-terminated (101̅ 0) surface (2.64 J/m 2 ) 25 is also expected to exist at low local concentrations of Mg.…”

Section: Model and Computational Detailsmentioning

confidence: 99%

“…The stability of that boron network was elucidated in recent work by Li et al, which revealed that boron-terminated basal surfaces are natively unstable to disordering, suggesting the possibility of additional hydrogen-prone defective sites on surfaces. 24 These studies further emphasize the need to understand the chemical process of hydrogen attack and incremental B−H coordination to form B x H y complexes at highly defective sites and interfaces.…”

Section: Introductionmentioning

confidence: 99%

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Understanding Hydrogenation Chemistry at MgB₂Reactive Edges fromAb InitioMolecular Dynamics

Ray

Klebanoff

Stavila

et al. 2022

ACS Appl. Mater. Interfaces

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Solid-state hydrogen storage materials often operate via transient, multistep chemical reactions at complex interfaces that are difficult to capture. Here, we use direct ab initio molecular dynamics simulations at accelerated temperatures and hydrogen pressures to probe the hydrogenation chemistry of the candidate material MgB2 without a priori assumption of reaction pathways. Focusing on highly reactive (101̅0) edge planes where initial hydrogen attack is likely to occur, we track mechanistic steps toward the formation of hydrogen-saturated BH4 – units and key chemical intermediates, involving H2 dissociation, generation of functionalities and molecular complexes containing BH2 and BH3 motifs, and B–B bond breaking. The genesis of higher-order boron clustering is also observed. Different charge states and chemical environments at the B-rich and Mg-rich edge planes are found to produce different chemical pathways and preferred speciation, with implications for overall hydrogenation kinetics. The reaction processes rely on B–H bond polarization and fluctuations between ionic and covalent character, which are critically enabled by the presence of Mg2+ cations in the nearby interphase region. Our results provide guidance for devising kinetic improvement strategies for MgB2-based hydrogen storage materials, while also providing a template for exploring chemical pathways in other solid-state energy storage reactions.

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Section: Resultsmentioning

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 89%

Section: Model and Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Understanding Hydrogenation Chemistry at MgB₂Reactive Edges fromAb InitioMolecular Dynamics

Ray

Klebanoff

Stavila

et al. 2022

ACS Appl. Mater. Interfaces

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Reactive Microneedle Patches with Antibacterial and Dead Bacteria‐Trapping Abilities for Skin Infection Treatment

Shan,

Wu,

Che

et al. 2024

Advanced Science

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Bacterial skin infections are highly prevalent and pose a significant public health threat. Current strategies are primarily focused on the inhibition of bacterial activation while disregarding the excessive inflammation induced by dead bacteria remaining in the body and the effect of the acidic microenvironment during therapy. In this study, a novel dual‐functional MgB2 microparticles integrated microneedle (MgB2 MN) patch is presented to kill bacteria and eliminate dead bacteria for skin infection management. The MgB2 microparticles not only can produce a local alkaline microenvironment to promote the proliferation and migration of fibroblasts and keratinocytes, but also achieve >5 log bacterial inactivation. Besides, the MgB2 microparticles effectively mitigate dead bacteria‐induced inflammation through interaction with lipopolysaccharide (LPS). With the incorporation of these MgB2 microparticles, the resultant MgB2 MN patches effectively kill bacteria and capture dead bacteria, thereby mitigating these bacteria‐induced inflammation. Therefore, the MgB2 MN patches show good therapeutic efficacy in managing animal bacterial skin infections, including abscesses and wounds. These results indicate that reactive metal borides‐integrated microneedle patches hold great promise for the treatment of clinical skin infections.

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Hydrogen Storage in Partially Exfoliated Magnesium Diboride Multilayers

Gunda

Ray

Klebanoff

et al. 2022

Small

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meet those requirements and constitute promising long-term solutions that reduce greenhouse gas emissions. [2] Hydrogen has the highest gravimetric energy density of any fuel (121 MJ kg −1 ), [3] and is considered a viable solution for ground transportation, aircraft, and marine vessels. [3,4] On the other hand, hydrogen is outperformed by hydrocarbon fuels in terms of volumetric energy density, motivating the development of alternative, higher-density materials-based storage methods. [5] Solid-state storage technology offers potential safety advantages (due to low operational pressure), with the additional benefit of higher volumetric density. [6] Materials considered for reversible H 2 storage include interstitial [7] and complex metal hydrides, [8] metal-organic frameworks (MOFs), [9] and various nanomaterials. [10] Metal hydrides are considered leading candidates for applications and use cases requiring high volumetric densities. [10][11][12] Unfortunately, the reaction enthalpy ΔH required to release H 2 from metal hydrides is typically too large, leading to undesirable high dehydriding temperatures.Nanostructuring can improve both the thermodynamics and kinetics of metal hydrides [11,12] via increased surface area and altered nanointerfaces. [10,[13][14][15] The resulting improvements Metal boride nanostructures have shown significant promise for hydrogen storage applications. However, the synthesis of nanoscale metal boride particles is challenging because of their high surface energy, strong inter-and intraplanar bonding, and difficult-to-control surface termination. Here, it is demonstrated that mechanochemical exfoliation of magnesium diboride in zirconia produces 3-4 nm ultrathin MgB 2 nanosheets (multilayers) in high yield. High-pressure hydrogenation of these multilayers at 70 MPa and 330 °C followed by dehydrogenation at 390 °C reveals a hydrogen capacity of 5.1 wt%, which is ≈50 times larger than the capacity of bulk MgB 2 under the same conditions. This enhancement is attributed to the creation of defective sites by ball-milling and incomplete Mg surface coverage in MgB 2 multilayers, which disrupts the stable boron-boron ring structure. The density functional theory calculations indicate that the balance of Mg on the MgB 2 nanosheet surface changes as the material hydrogenates, as it is energetically favorable to trade a small number of Mg vacancies in Mg(BH 4 ) 2 for greater Mg coverage on the MgB 2 surface. The exfoliation and creation of ultrathin layers is a promising new direction for 2D metal boride/borohydride research with the potential to achieve high-capacity reversible hydrogen storage at more moderate pressures and temperatures.

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Spontaneous dynamical disordering of borophenes in MgB2 and related metal borides

Cited by 22 publications

References 65 publications

Understanding Hydrogenation Chemistry at MgB₂Reactive Edges fromAb InitioMolecular Dynamics

Understanding Hydrogenation Chemistry at MgB₂Reactive Edges fromAb InitioMolecular Dynamics

Reactive Microneedle Patches with Antibacterial and Dead Bacteria‐Trapping Abilities for Skin Infection Treatment

Hydrogen Storage in Partially Exfoliated Magnesium Diboride Multilayers

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Spontaneous dynamical disordering of borophenes in MgB2 and related metal borides

Cited by 22 publications

References 65 publications

Understanding Hydrogenation Chemistry at MgB2Reactive Edges fromAb InitioMolecular Dynamics

Understanding Hydrogenation Chemistry at MgB2Reactive Edges fromAb InitioMolecular Dynamics

Reactive Microneedle Patches with Antibacterial and Dead Bacteria‐Trapping Abilities for Skin Infection Treatment

Hydrogen Storage in Partially Exfoliated Magnesium Diboride Multilayers

Contact Info

Product

Resources

About

Understanding Hydrogenation Chemistry at MgB₂Reactive Edges fromAb InitioMolecular Dynamics

Understanding Hydrogenation Chemistry at MgB₂Reactive Edges fromAb InitioMolecular Dynamics