First-Principles Models of Facilitating H<sub>2</sub> Transport through Metal Films Using Spillover

Hao, Shiqiang; Sholl, David S.

doi:10.1021/jp3090342

Cited by 17 publications

(12 citation statements)

References 37 publications

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“…9,[18][19][20] The enhancement of hydrogen storage on adsorbents such as activated carbon may be achieved by exploiting hydrogen spillover. [21][22][23][24][25][26] The dispersal of metal catalysts onto the surface allows for the dissociation of dihydrogen molecules, leading to the subsequent spillover of hydrogen atoms to carbon, thus in turn, increasing the amount of hydrogen sorbed. 27,28 As a 3 metal catalyst, palladium exhibits a good compromise between suitable dissociation abilities and low adherence strengths for use in hydrogen spillover.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Electrochemical Study of Pd-Based Trimetallic Nanoparticles for Enhanced Hydrogen Storage

Ostrom

Chen

2013

J. Phys. Chem. C

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The success of acceptable hydrogen storage capacities on high surface area carbon materials at ambient temperature requires the combination of both physisorption and chemisorption. Despite the sole reliance on physisorption for hydrogen uptake in carbon, the dispersal of transition metal catalysts on carbon materials significantly enhances hydrogen uptake at ambient temperatures, via the process of hydrogen spillover. In the present study, hydrogen electrosorption onto activated carbon materials modified with different tri-metallic dissociation catalysts (Pd-Ag-Cd) was investigated in an acidic medium using cyclic voltammetry and chronoamperometry. A significant synergistic effect on hydrogen storage was observed, which could be attributed to the electrochemical reduction of hydrogen ions initially at the Pd-based nanoparticles and the hydrogen surface diffusion subsequently to the activated carbon. Utilizing electrochemical methods, the optimized composition of the Pd-Ag-Cd alloys was determined to be Pd 80 Ag 10 Cd 10 with the highest hydrogen sorption capacity at a hydrogen desorption charge of 18.49 C/cm 2 ·mg.With increased kinetics and a decrease in the phase transition, the significant enhancement of hydrogen sorption, in comparison to the Pd-Ag and Pd-Cd bi-metallic alloys, was further demonstrated, making Pd-Ag-Cd catalysts attractive for use as hydrogen dissociation catalysts for applications in both hydrogen purification and storage.

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Section: Introductionmentioning

confidence: 99%

Synthesis and Electrochemical Study of Pd-Based Trimetallic Nanoparticles for Enhanced Hydrogen Storage

Ostrom

Chen

2013

J. Phys. Chem. C

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“…However, to understand the effectiveness of V 2 O 3 (0001) as a catalyst, the dissociation barrier and dissociated H adsorption energy calculated in this work are compared to other known catalysts in Table . Pd is well-known as an excellent dissociation catalyst with a negligible barrier for dissociation and small E ads H , whereas Mo 2 C and TiC are included as spillover catalysts for membrane applications. Additionally, V 2 O 5 and VO 2 provide comparisons among the different oxidation states of VO x .…”

Section: Discussionmentioning

confidence: 99%

Experimental and Theoretical Insights into the Potential of V₂O₃ Surface Coatings for Hydrogen Permeable Vanadium Membranes

et al. 2018

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A grand challenge of vanadium-based H2 permeable membranes is the development of effective, cheap, and stable catalysts to facilitate H2 dissociation and recombination. This work investigates a facile air treatment to form catalytically active vanadium oxide on the surfaces of dense vanadium foils. The treatment consisted of short air exposure followed by H2 reduction at 823 K, which produced a well-faceted and nanocrystalline V2O3 layer on the foil surfaces. The resulting membranes displayed a stable H2 permeability of 2 ± 0.25 × 10–8 mol·m–1·s–1·Pa–0.5, but transient declines in permeation were observed when operated at both elevated and reduced temperatures. DFT calculations revealed that V2O3 (0001) surfaces display barriers and adsorption energies for H2 dissociation/recombination that are comparable to those of known H2 activation catalysts. It was found that H2 dissociation is expected to proceed spontaneously on metal-terminated V2O3, with recombinative-desorption anticipated as the rate limiting step.

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“…A recent DFT analysis of our membranes [77] identified H 2 desorption on the permeate side as a potential bottleneck. In both cases improved catalytic activity at the membrane surface would be required to improve performance.…”

Section: Examination Of Pt Co-catalystsmentioning

confidence: 93%

“…The purpose of these studies was to try to investigate the importance of the hydrogen dissociation rate on the overall transport rate of hydrogen through a Mo 2 C/V foil membrane. We also were interested in if the presence of an additional hydrogen dissociation catalyst on the permeate side could decrease the desorption resistance recently [77] postulated by Sholl. Figure 7-16 below compares the pure hydrogen flux of membrane Mo 2 C-4 with an identical membrane sputtered with 2 nm of a Pt co-catalyst on both sides at 600 °C.…”

Section: Examination Of Pt Co-catalystsmentioning

confidence: 99%

Nanoporous, Metal Carbide, Surface Diffusion Membranes for High Temperature Hydrogen Separations

Way¹,

Wolden²

2013

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Colorado School of Mines (CSM) developed high temperature, hydrogen permeable membranes that contain no platinum group metals with the goal of separating hydrogen from gas mixtures representative of gasification of carbon feedstocks such as coal or biomass in order to meet DOE NETL 2015 hydrogen membrane performance targets. We employed a dual synthesis strategy centered on transition metal carbides. In the first approach, novel, high temperature, surface diffusion membranes based on nanoporous Mo 2 C were fabricated on ceramic supports. These were produced in a two step process that consisted of molybdenum oxide deposition followed by thermal carburization. Our best Mo 2 C surface diffusion membrane achieved a pure hydrogen flux of 367 SCFH/ft 2 at a feed pressure of only 20 psig. The highest H 2 /N 2 selectivity obtained with this approach was 4.9. A transport model using "dusty gas" theory was derived to describe the hydrogen transport in the Mo 2 C coated, surface diffusion membranes. The second class of membranes developed were dense metal foils of BCC metals such as vanadium coated with thin (< 60 nm) Mo 2 C catalyst layers. We have fabricated a Mo 2 C/V composite membrane that in pure gas testing delivered a H 2 flux of 238 SCFH/ft 2 at 600 °C and 100 psig, with no detectable He permeance. This exceeds the 2010 DOE Target flux. This flux is 2.8 times that of pure Pd at the same membrane thickness and test conditions and over 79% of the 2015 flux target. In mixed gas testing we achieved a permeate purity of ≥99.99%, satisfying the permeate purity milestone, but the hydrogen permeance was low, ~0.2 SCFH/ft 2 .psi. However, during testing of a Mo 2 C coated Pd alloy membrane with DOE 1 feed gas mixture a hydrogen permeance of >2 SCFH/ft 2 .psi was obtained which was stable during the entire test, meeting the permeance associated with the 2010 DOE target flux. Lastly, the Mo 2 C/V composite membranes were shown to be stable for at least 168 hours = one week, including cycling at high temperature and alternating He/H 2 exposure.4

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First-Principles Models of Facilitating H₂ Transport through Metal Films Using Spillover

Cited by 17 publications

References 37 publications

Synthesis and Electrochemical Study of Pd-Based Trimetallic Nanoparticles for Enhanced Hydrogen Storage

Synthesis and Electrochemical Study of Pd-Based Trimetallic Nanoparticles for Enhanced Hydrogen Storage

Experimental and Theoretical Insights into the Potential of V₂O₃ Surface Coatings for Hydrogen Permeable Vanadium Membranes

Nanoporous, Metal Carbide, Surface Diffusion Membranes for High Temperature Hydrogen Separations

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First-Principles Models of Facilitating H2 Transport through Metal Films Using Spillover

Cited by 17 publications

References 37 publications

Synthesis and Electrochemical Study of Pd-Based Trimetallic Nanoparticles for Enhanced Hydrogen Storage

Synthesis and Electrochemical Study of Pd-Based Trimetallic Nanoparticles for Enhanced Hydrogen Storage

Experimental and Theoretical Insights into the Potential of V2O3 Surface Coatings for Hydrogen Permeable Vanadium Membranes

Nanoporous, Metal Carbide, Surface Diffusion Membranes for High Temperature Hydrogen Separations

Contact Info

Product

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About

First-Principles Models of Facilitating H₂ Transport through Metal Films Using Spillover

Experimental and Theoretical Insights into the Potential of V₂O₃ Surface Coatings for Hydrogen Permeable Vanadium Membranes