Synthesis of Colloidal Magnesium: A Near Room Temperature Store for Hydrogen

Aguey‐Zinsou, Kondo‐François; Ares-Fernández, José-Ramón

doi:10.1021/cm702897f

Cited by 186 publications

(150 citation statements)

References 28 publications

Supporting

Mentioning

138

Contrasting

Unclassified

Order By: Relevance

“…In fact, there has been great interest for Mg nanoparticles with sizes below 5 nm because there are indications that the kinetics and thermodynamics of hydrogen absorption/ desorption with respect to that of bulk Mg are improved. 11,12 In recent publications of Mg nanoparticles with size Ͻ5 nm produced by various methods, it was shown that H 2 absorption and desorption is possible at relatively low temperatures, ϳ100°C, in comparison with the bigger nanoparticles which required about 300°C. 11,12 Moreover, in Mg-based multilayers, it was shown that the equilibrium pressure is modified by two orders of magnitude, when a thin film is clamped by surrounding Pd layers.…”

Section: E Annealing Of Small "<10 Nm… Mg Nanoparticlesmentioning

confidence: 99%

“…11,12 In recent publications of Mg nanoparticles with size Ͻ5 nm produced by various methods, it was shown that H 2 absorption and desorption is possible at relatively low temperatures, ϳ100°C, in comparison with the bigger nanoparticles which required about 300°C. 11,12 Moreover, in Mg-based multilayers, it was shown that the equilibrium pressure is modified by two orders of magnitude, when a thin film is clamped by surrounding Pd layers. 24 We find here that the annealing of Mg nanoparticles ͑prepared from gas phase synthesis͒ in vacuum at 60°C for 24 h leads to voids in the smaller nanoparticles of size ϳ15-20 nm ͓Figs.…”

Section: E Annealing Of Small "<10 Nm… Mg Nanoparticlesmentioning

confidence: 99%

“…Note that for Mg nanoparticles prepared by other methods in the size range below 5 nm no explicit discussion or consideration is given to the Kirkendall effect associated with oxidation. [11][12][13][14] …”

Section: E Annealing Of Small "<10 Nm… Mg Nanoparticlesmentioning

confidence: 99%

“…9,10 According to calculations, the heat of formation increases from 66.9 to 79.5 kJ/mol when the particle size varies from 0.6 to 2 nm and approaches the bulk value ͑ϳ83.7 kJ/ mol͒ beyond 2 nm. 9 Therefore, much effort has been devoted to the preparation of Mg nanoparticles with sizes below 5 nm by various routes, e.g., electrochemical reduction, 11 solvated metal atom dispersion, 12 carbon supported melt infiltration, 13 and a sonoelectrochemical method. 14 Indeed, it has been reported that the desorption temperature T d can be decreased to 85 and 115°C compared to T d Ͼ 350°C for bulk Mg. 11,12 Nanoconfinement of MgH 2 nanoparticles incorporated in carbon aerogel scaffold prohibits nanoparticles to coarsen and leads to increased number of hydrogenation/dehydrogenation cycles and with faster dehydrogenation kinetics compared to the ball milled nanostructured materials.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Thermal stability of gas phase magnesium nanoparticles

Krishnan

Kooi

Palasantzas

et al. 2010

Journal of Applied Physics

View full text Add to dashboard Cite

In this work we present a unique transmission electron microscopy study of the thermal stability of gas phase synthesized Mg nanoparticles, which have attracted strong interest as high capacity hydrogen storage materials. Indeed, Mg nanoparticles with a MgO shell ͑ϳ3 nm thick͒ annealed at 300°C show evaporation, void formation, and void growth in the Mg core both in vacuum and under a high pressure gas environment. This is mainly due to the outward diffusion and evaporation of Mg with the simultaneously inward diffusion of vacancies leading to void growth ͑Kirkendall effect͒. The rate of Mg evaporation and void formation depends on the annealing conditions. In vacuum, and at T = 300°C, the complete evaporation of the Mg core takes place ͑within a few hours͒ for sizes ϳ15-20 nm. Void formation and growth has been observed for particles with sizes ϳ20-50 nm, while stable Mg nanoparticles were observed for sizes Ͼ50 nm. Furthermore, even at relative low temperature annealing ͑as low as 60°C͒, void formation and growth occurs in 15-20 nm sized Mg nanoparticles, indicating that voiding will be even more dominant for nanoparticles smaller than 10 nm. Our findings confirm that Mg evaporation and void formation in nanoparticles with sizes less than 50 nm present formidable barriers for their applicability in hydrogen storage, but also could inspire future research directions to overcome these obstacles.

show abstract

Section: E Annealing Of Small "<10 Nm… Mg Nanoparticlesmentioning

confidence: 99%

Section: E Annealing Of Small "<10 Nm… Mg Nanoparticlesmentioning

confidence: 99%

Section: E Annealing Of Small "<10 Nm… Mg Nanoparticlesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thermal stability of gas phase magnesium nanoparticles

Krishnan

Kooi

Palasantzas

et al. 2010

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…10 Nanostructuring and doping are popular methods of modifying properties of materials, as is the case for MgH 2 . Nanostructuring, via ball-milling, 11,12 or via wet-chemical synthesis using surface monolayer protection, 13,14,15 has being perceived to reduce the enthalpy for dehydrogenation. If H 2 release is a surface-desorption limited process, 16 then nanostructuring may modify surface curvature, hence dehydrogenation thermodynamics, and increase the specific surface area, hence dehydrogenation kinetics.…”

Section: : Introductionmentioning

confidence: 99%

MgH₂ Dehydrogenation Thermodynamics: Nanostructuring and Transition Metal Doping

Shevlin

Guo

2013

J. Phys. Chem. C

View full text Add to dashboard Cite

Controversy currently exists as to the true effects of nanostructuring and transition-metal doping on the dehydrogenation of MgH 2 . Following extensive datamining of structurally related compounds, we present for the first time, especially for the larger clusters, new stable structures for (MgH 2 ) n clusters, where n = 1 to 10. Using density functional theory and the harmonic approximation we determine the enthalpy of dehydrogenation for all of these clusters. All clusters have very different structures from the bulk, with one-to fourfold hydrogen coordinations observed, and three-to seven-fold magnesium coordinations. We find that, apart from the smallest clusters, enthalpy is larger than for the bulk. Nanostructuring does not improve dehydrogenation enthalpies. We attribute this to surface energy effects; as the (MgH 2 ) n clusters reduce in size bulk cuts become less stable until a stabilising reconstruction occurs which strongly modifies the cluster structure. This increases the magnitude of the dehydrogenation enthalpy. Accurately determining the structures of clusters is essential in determining gas-release thermodynamics for applications. Additionally we investigate modifications of these

show abstract

Nanoparticles and 3D Supported Nanomaterials

Jongh

Adelhelm

2010

Handbook of Hydrogen Storage

View full text Add to dashboard Cite

Many light metal hydride systems are discussed in this book. However, none of them is currently able to meet all the demands for practical on-board hydrogen storage: high volumetric and gravimetric density, reasonably high hydrogen equilibrium pressure at room-or fuel cell operating-temperature, fast kinetics for both loading and unloading and ample reversibility. A variety of strategies is being pursued to meet these goals: ball-milling to improve the kinetics and add catalysts, searching for new yet unknown material compositions, and mixing several different compounds (reactive hydride composites or destabilized hydrides) [1-6]. Some approaches are remarkably successful, such as ball-milling in general to improve the kinetics [2,3], and the addition of a small amount of a Ti-based catalyst to improve the kinetics of both hydrogenation and dehydrogenation of NaAlH 4 [1]. However although steady progress is reported, we are still far from meeting simultaneously all criteria for on-board storage.In this chapter we discuss an alternative approach: altering the properties of a given material by nanosizing and/or supporting the material. Although this approach is relatively new for hydrogen storage applications, it has been known for a long time in other fields such as heterogeneous catalysis, where a high surface/volume ratio is essential. Interesting material classes are unsupported clusters, nanoparticles and nanostructures, and 3D supported (or scaffolded) nanomaterials. In general the crystallite size of the materials discussed is below 10 nm. This is a clear distinction from materials prepared by ball-milling, presently the most common processing technique, by which crystallite sizes of 10-30 nm or above (depending on the material) are achieved. Furthermore, in general (though not always) the alternative preparation techniques used to obtain these nanosized materials (gas-phase deposition, melt infiltration, or solution-based synthesis techniques) allow a much better Handbook of Hydrogen Storage. Edited by Michael Hirscher

show abstract

Synthesis of Colloidal Magnesium: A Near Room Temperature Store for Hydrogen

Cited by 186 publications

References 28 publications

Thermal stability of gas phase magnesium nanoparticles

Thermal stability of gas phase magnesium nanoparticles

MgH₂ Dehydrogenation Thermodynamics: Nanostructuring and Transition Metal Doping

Nanoparticles and 3D Supported Nanomaterials

Contact Info

Product

Resources

About

Synthesis of Colloidal Magnesium: A Near Room Temperature Store for Hydrogen

Cited by 186 publications

References 28 publications

Thermal stability of gas phase magnesium nanoparticles

Thermal stability of gas phase magnesium nanoparticles

MgH2 Dehydrogenation Thermodynamics: Nanostructuring and Transition Metal Doping

Nanoparticles and 3D Supported Nanomaterials

Contact Info

Product

Resources

About

MgH₂ Dehydrogenation Thermodynamics: Nanostructuring and Transition Metal Doping