Size-Dependent Hydrogen Sorption in Ultrasmall Pd Clusters Embedded in a Mesoporous Carbon Template

Zlotea, Claudia; Cuevas, Fermín; Paul‐Boncour, V.; Leroy, Éric; Dibandjo, Philippe; Gadiou, Roger; Vix‐Guterl, Cathie; Latroche, M.

doi:10.1021/ja101795g

Cited by 95 publications

(91 citation statements)

References 43 publications

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“…At 298 K and high-pressure (Figure 7b), both adsorption and desorption PCI isotherms exhibit linear behavior with low hydrogen uptake (≤0.26 wt%). Such a low capacity is attributed to the low enthalpy of hydrogen adsorption [31] and concurs with earlier reports on platinum doping in super activated carbon [18] and palladium in mesoporous carbon [32]. Similar capacities have been reported for hydrogen storage in activated carbon of even higher surface area As = 3,500 g/cm 3 [23].…”

Section: Hydrogen Storage Measurementssupporting

confidence: 90%

“…At room temperature and low pressure, Pd-anchored activated carbon has higher capacity than all other materials. This confirms the formation of palladium hydride at room temperature and low pressure, as demonstrated previously [28,29,32]. However, at high pressure, the favorable effect of palladium hydride formation is counteracted by the weight of the dopant, the filling of adsorbent micropores and pore blocking.…”

Section: Hydrogen Storage Measurementssupporting

confidence: 89%

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Hydrogen Storage in Pristine and d10-Block Metal-Anchored Activated Carbon Made from Local Wastes

et al. 2015

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Activated carbon has been synthesized from local palm shell, cardboard and plastics municipal waste in the Kingdom of Saudi Arabia. It exhibits a surface area of 930 m 2 /g and total pore volume of 0.42 cm 3 /g. This pristine activated carbon has been further anchored with nickel, palladium and platinum metal particles by ultrasound-assisted impregnation. Deposition of nanosized Pt particles as small as 3 nm has been achieved, while for Ni and Pd their size reaches 100 nm. The solid-gas hydrogenation properties of the pristine and metal-anchored activated carbon have been determined. The pristine material exhibits a reversible hydrogen storage capacity of 2.3 wt% at 77 K and 3 MPa which is higher than for the doped ones. In these materials, the spillover effect due to metal doping is of minor importance in enhancing the hydrogen uptake compared with the counter-effect of the additional mass of the metal particles and pore blocking on the carbon surface. OPEN ACCESS

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Section: Hydrogen Storage Measurementssupporting

confidence: 90%

Section: Hydrogen Storage Measurementssupporting

confidence: 89%

Hydrogen Storage in Pristine and d10-Block Metal-Anchored Activated Carbon Made from Local Wastes

et al. 2015

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“…The small size of the obtained NPs and their dense loading inside the silica pores prevented us from performing quantitative TEM size distribution analysis for this sample. XRPD analysis (Figure 3) confirmed the formation of the particles with fcc structure for all the samples, which is in good agreement with the results frequently reported for nanostructured palladium samples [16,42]. During the refinement, we obtained the following lattice parameters: 3.907, 3.891, 3.893, and 4.01 Å for Pd-NPsNaBH₄, Pd-NPshydrazine, Pd-NPsammonia,hydrazine, and Pd-NPsPEG, respectively (see Table 1 for the error bars).…”

Section: Structure and Morphology Of Pd/sio2supporting

confidence: 90%

“…In particular, palladium is one of the best-performing metal catalysts for selective hydrogenation of alkynes [10][11][12][13][14]. Numerous studies focus on the size-and shape-dependent properties of palladium NPs [15][16][17][18][19], indicating that controlling the size and shape distribution of NPs during synthesis is an important step in designing functional materials with the required parameters for practical applications.…”

Section: Introductionmentioning

confidence: 99%

Chemical Synthesis and Characterization of Pd/SiO2: The Effect of Chemical Reagent

Bugaev

Polyakov

Tereshchenko

et al. 2018

Metals

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The size and shape distribution of metal nanoparticles (NPs) are important parameters that need to be tuned in order to achieve desired properties of materials for practical applications. In the current work, we present the synthesis of palladium NPs supported on silica by three different methods, applying reduction by sodium borohydride, hydrazine vapors, and polyethylene glycol (PEG). The synthesized materials were characterized by X-ray diffraction, X-ray fluorescence, transmission electron microscopy, surface area and porosity measurements, and thermogravimetric analysis. Similar nanoparticle sizes with narrow size distribution centered at 8 nm were obtained after reduction by sodium borohydride and hydrazine vapors, whereas the smallest particle size of about 4.8 nm was obtained after reduction by PEG. The effect of modification of the initial palladium chloride compound by ammonium hydroxide was found to lead to the formation of larger particles with average size of 15 nm and broader size distribution. In addition, the process of the reduction of palladium by PEG at different reduction stages was monitored by UV-Vis spectroscopy. CO-stripping voltammetry showed that reduction in hydrazine and in PEG allowed the preparation of Pd NPs with high electrochemically-active surface area. Such NPs are promising materials for electrocatalysis.

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“…Typically, a metal salt is used as precursor for porous host impregnation followed by a reduction step (H2, NaBH4, etc.) at different temperatures depending on the reducing agent (Narehood et al, 2009;Zlotea et al, 2010bZlotea et al, , 2015bEssinger-Hileman et al, 2011). For pure Pd and Rh nanoparticles, the use of high temperature, typically above 300°C, as well as high metal loadings usually induces the growth of nanoparticles size and the increase of the particle size distribution (Zhao et al, 2012;Bastide et al, 2013;Zlotea et al, 2015b).…”

Section: Synthesismentioning

confidence: 99%

Experimental Challenges in Studying Hydrogen Absorption in Ultrasmall Metal Nanoparticles

et al. 2016

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Recent advances on synthesis, characterization, and hydrogen absorption properties of ultrasmall metal nanoparticles (defined here as objects with average size ≤3 nm) are briefly reviewed in the first part of this work. The experimental challenges encountered in performing accurate measurements of hydrogen absorption in Mg-and noble metal-based ultrasmall nanoparticles are addressed. The second part of this work reports original results obtained for ultrasmall bulk-immiscible Pd-Rh nanoparticles. Carbonsupported Pd-Rh nanoalloys in the whole binary chemical composition range have been successfully prepared by liquid impregnation method followed by reduction at 300°C. EXAFS investigations suggested that the local structure of these nanoalloys is partially segregated into Rh-rich core and Pd-rich surface coexisting within the same nanoparticles. Downsizing to ultrasmall dimensions completely suppresses the hydride formation in Pd-rich nanoalloys at ambient conditions, contrary to bulk and larger nanosized (5-6 nm) counterparts. The ultrasmall Pd90Rh10 nanoalloy can absorb hydrogen-forming solid solutions under these conditions, as suggested by in situ X-ray diffraction (XRD). Apart from this composition, common laboratory techniques, such as in situ XRD, DSC, and PCI, failed to clarify the hydrogen interaction mechanism: either adsorption on developed surfaces or both adsorption and absorption with formation of solid solutions. Concluding insights were brought by in situ EXAFS experiments at synchrotron: ultrasmall Pd75Rh25 and Pd50Rh50 nanoalloys absorb hydrogen-forming solid solutions at ambient conditions. Moreover, the hydrogen solubility in these solid solutions is higher with increasing Pd content, and this trend can be understood in terms of hydrogen preferential occupation in the Pd-rich regions, as suggested by in situ EXAFS. The Rh-rich nanoalloys (Pd25Rh75 and Pd10Rh90) only adsorb hydrogen on the developed surface of ultrasmall nanoparticles. In summary, in situ characterization techniques carried out at large-scale facilities are unique and powerful tools for in-depth investigation of hydrogen interaction with ultrasmall nanoparticles at local level.

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Size-Dependent Hydrogen Sorption in Ultrasmall Pd Clusters Embedded in a Mesoporous Carbon Template

Cited by 95 publications

References 43 publications

Hydrogen Storage in Pristine and d10-Block Metal-Anchored Activated Carbon Made from Local Wastes

Hydrogen Storage in Pristine and d10-Block Metal-Anchored Activated Carbon Made from Local Wastes

Chemical Synthesis and Characterization of Pd/SiO2: The Effect of Chemical Reagent

Experimental Challenges in Studying Hydrogen Absorption in Ultrasmall Metal Nanoparticles

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