Study of the interplay between N-graphene defects and small Pd clusters for enhanced hydrogen storage via a spill-over mechanism

Rangel, Eduardo; Sansores, Enrique; Vallejo, E.; Hernández–Hernández, A.; López‐Pérez, Pablo A.

doi:10.1039/c6cp06497c

Cited by 42 publications

(19 citation statements)

References 51 publications

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“…On the other hand, in the field of catalytic hydrogenation reactions, one important step is the generation of activated hydrogen. This is traditionally achieved through the catalytic dissociation of molecular hydrogen using different type of catalysts . It has been found that especially efficient has been the use of small catalytic particles, such as nanoparticles, small metallic clusters, and even individual atoms, supported on different type of surfaces .…”

Section: Introductionmentioning

confidence: 99%

“…It has been found that especially efficient has been the use of small catalytic particles, such as nanoparticles, small metallic clusters, and even individual atoms, supported on different type of surfaces . In the case of metallic clusters supported on surfaces, one relevant sequence of catalytic processes starts with the hydrogen dissociation, followed by the diffusion of hydrogen atoms through the metallic clusters, and finally, the induced spillover of the hydrogen atom over the surface, wherein the hydrogen–surface interaction is weak enough to allow easy access of reactive hydrogen . In this regard, gold has been used both, as noble metal cluster catalyst, or as support surface .…”

Section: Introductionmentioning

confidence: 99%

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Activation and diffusion of ammonia borane hydrogen on gold tetramers

Mejía

Ferraro

Osorio

et al. 2017

Int J of Quantum Chemistry

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One of the most serious candidates for safe storage of high hydrogen densities is ammonia borane, AB. Likewise, one of the most versatile catalysts known is gold in the form of atomic clusters. Taking these elements into account, in this work a density functional theory -based study about initial activation, detachment, and diffusion of ammonia borane hydrogen on gold tetramer, as a catalyst model, is developed. It was found that the total process is exergonic and that the hydrogen diffusion occurs with very low energy barriers. The process has a hydrogen detachment energy barrier lower than the one of the uncatalyzed AB, and that is easily overcome by the energy expelled in the previous stage of formation of the initial activated species. Additionally, all the process is assisted by the fluxionality of the gold cluster, and occurs via a unique catalytically activated initial species, which contains a three-center simultaneous interaction at the catalytically activated zone.ammonia borane, gold cluster catalyst, gold-fluxionality, theoretical study, three-center bonding | I N TR ODU C TI ONResearch about new ways for practical, safe, and economically convenient storage and release of large quantities of hydrogen in small volumes is today a very important issue. [1,2] Hydrogen has an energy content by mass almost three times superior to petroleum, [3] is the most abundant substance in the universe, is source-independent, and its combustion product, water, is environmentally friendly. Additionally, the availability of activated hydrogen is highly relevant for a large number of reactions in the chemical industry, where reduction or hydrogenation are necessary steps. [4,5] Among lightweight hydrogen storage materials, ammonia borane, AB (H 3 BNH 3 ), is a substance that contains large amounts of hydrogen (a total of 19.6 wt.%), [3] which is relatively easy to extract, either by direct or by assisted thermolysis, [6,7] by catalyzed room temperature solvolysis, [3,[8][9][10][11] or by other methods. [12][13][14][15] Additionally, AB can be easily and safely transported, [16] because, on the one hand, is a relatively stable solid at room conditions, [3,6,16] and is a substance soluble in many solvents, such as water, methanol, and tetraglyme. [3,[8][9][10][11][12] It has been found that the use of transition metals as catalysts in the AB dehydrogenation has the advantage of avoiding the expenditure of large amounts of energy, necessary for the hydrogen release. [7,[16][17][18] Even, in some cases, the catalysis has emerged as a solution to diminish the unwanted by-products of hydrogen release. [10,12,18] Transition metals of different nature, both noble and non-noble, as well as binary or tertiary combinations among them, have shown catalytic activity toward the extraction of hydrogen from AB. [3,[8][9][10][11][12]17,18] In the case of nanoparticles, the studies show that although some transition metals are better than others, the decrease in size (within certain limits and conditions [19] ) of the nanoparticles of the ...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Activation and diffusion of ammonia borane hydrogen on gold tetramers

Mejía

Ferraro

Osorio

et al. 2017

Int J of Quantum Chemistry

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“…Keywords Size-dependent · Nanoparticle · Melting · Enthalpy 1 Introduction Palladium nanoparticles have received growing interest due to their novel properties such as size (Chen et al, 2016) and shape (facet) (Wang et al, 2017) dependent catalytic activity, controlled oligomerization (Zhivonitko et al, 2016) and enhanced hydrogen storage (Rangel et al, 2016). However, due to the higher surface to volume ratio (Schmidt et al, 1998;Safaei et al, 2008), the nanoparticles are known as the most unstable structures among different nanosolids.…”

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confidence: 99%

Size and shape-dependent melting mechanism of Pd nanoparticles

et al. 2018

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Molecular dynamics simulation is employed to understand the thermodynamic behavior of cuboctahedron (cub) and icosahedron (ico) nanoparticles with 2 − 20 number of full shells. The original embedded atom method (EAM) was compared to the more recent highly optimized version as interatomic potential. The thermal stability of clusters were probed using potential energy and specific heat capacity as well as structure analysis by radial distribution function (G(r)) and common neighbor analysis (CNA), simultaneously, to make a comprehensive picture of the solid state and melting transitions. The result shows ico is the only stable shape of small clusters (Pd 55 -Pd 309 using original EAM and Pd 55 using optimized version) those are melting uniformly due to their small diameter. An exception is cub Pd 309 modeled via optimized EAM that transforms to ico at elevated temperatures. A similar cub to ico transition was predicted by original EAM for Pd 923 -Pd 2075 clusters while for the larger clusters both cub and ico are stable up to the melting point. As detected by G(r) and CNA, moderate and large cub clusters were showing surface melting by nucleation of the liquid phase at (100) planes and growth of liquid phase at the surface before inward growth. While diagonal (one corner to another) melting was dominating over ico clusters owing to their partitioned

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“… 18 Pd can store H 2 via PdH formation and supply H atoms to nearby medium by so-called “spill-over” mechanism. 19 Moreover, the reactive termination groups and unique layered structure of ML-Ti 3 C 2 T x may let this material considered for hydrogen storage. 20 …”

Section: Introductionmentioning

confidence: 99%