Effect of Nitrogen Doping on Hydrogen Storage Capacity of Palladium Decorated Graphene

Parambhath, Vinayan Bhagavathi; Nagar, Rupali; Ramaprabhu, Sundara

doi:10.1021/la301232r

Cited by 284 publications

(139 citation statements)

References 62 publications

Supporting

Mentioning

135

Contrasting

Unclassified

Order By: Relevance

“…[18][19][20][21][22][23][24][25][26] The metals mostly used in those investigations are alkali metals 18,19 and some transition metals like vanadium, palladium, and platinum. [22][23][24][25][26][27] To explain the observed enhancement of the hydrogen adsorption, a mechanism of spillover 28,29 has generally been assumed. [22][23][24][25][26][27]30,31 In that mechanism, the hydrogen molecules are first adsorbed and dissociated on the surface of the metallic nanoparticles, and are next transported onto the surface of the substrate carbon material.…”

Section: Introductionmentioning

confidence: 99%

“…[22][23][24][25][26][27] To explain the observed enhancement of the hydrogen adsorption, a mechanism of spillover 28,29 has generally been assumed. [22][23][24][25][26][27]30,31 In that mechanism, the hydrogen molecules are first adsorbed and dissociated on the surface of the metallic nanoparticles, and are next transported onto the surface of the substrate carbon material. However, in our opinion, the validity of that spillover idea has not been scrutinized critically.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Is Spillover Relevant for Hydrogen Adsorption and Storage in Porous Carbons Doped with Palladium Nanoparticles?

et al. 2016

View full text Add to dashboard Cite

Experiments have shown that the efficiency of nanoporous carbons to store hydrogen becomes enhanced by doping the material with metallic nanoparticles. In particular, doping with palladium has been used with success. The hypothesis to justify the enhancement has been that the Pd nanoparticles dissociate the hydrogen molecules and then the hydrogen atoms spill over the carbon substrate, where the hydrogen is retained. To test this hypothesis we have performed ab initio molecular dynamics simulations of the deposition of molecular hydrogen on Pd nanoparticles (Pd 6 and Pd 13 ) supported on graphene, which is a good model for the wall of a carbon nanopore. Three channels have been identified in the simulations: bouncing off the molecule, molecular adsorption, and dissociation of the molecule in two H atoms. The relative percentage of those channels is sensitive to the size of the Pd particle. Dissociation occurs more frequently on Pd 13 and it generally takes place on the lateral regions of the Pd particles.However, in our simulations we have not found a single case of H atoms or H 2 molecules spilling over the carbon substrate. We have also tested the situation when several H atoms are preadsorbed on the Pd 6 and Pd 13 particles and found that not a single dissociation event occurs on these H-saturated nanoparticles. These results lead us to cast strong doubts on the validity of the spillover mechanism for explaining the enhancement of hydrogen adsorption on porous carbons doped with transition metal nanoparticles.2

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Is Spillover Relevant for Hydrogen Adsorption and Storage in Porous Carbons Doped with Palladium Nanoparticles?

et al. 2016

View full text Add to dashboard Cite

show abstract

“…[23][24][25][26][27][28][29][30][31] In many of these studies H 2 sorption was reported for single sample and using only one sorption isotherm, without analysis of reproducibility of sorption in several cycles. Theoretical studies do not predict exceptional H 2 sorption for graphene by physisorption relative to other carbon materials with comparable SSA.…”

Section: Introductionmentioning

confidence: 99%

“…Pt, Pd, TiO 2 ) provides increase of hydrogen sorption by 10-500%. [28,31,37] In some studies the hydrogen storage values which satisfy and even exceed DOE targets have been reported for temperatures near ambient and assigned to "spillover" mechanism. For example, Parambhath et al reported uptake of ~3wt% for Pd decorated material with SSA of ~470 m 2 /g already at 40bar H 2 pressure.…”

Section: Introductionmentioning

confidence: 99%

Graphene decorated with metal nanoparticles: Hydrogen sorption and related artefacts

Klechikov

Sun

et al. 2017

Microporous and Mesoporous Materials

View full text Add to dashboard Cite

Hydrogen sorption by reduced graphene oxides (r-GO) is not found to increase after decoration with Pd and Pt nanoparticles. Treatments of metal decorated samples using annealing under hydrogen or air were tested as a method to create additional pores by effects of r-GO etching around nanoparticles. Increase of Specific Surface Area (SSA) was observed for some air annealed r-GO samples. However, the same treatments applied to activated r-GO samples with microporous nature and higher surface area result in breakup of structure and dramatic decrease of SSA. Our experiments have not revealed effects which could be attributed to spillover in hydrogen sorption on Pd or Pt decorated graphene. However, we report irreversible chemisorption of hydrogen for some samples which can be mistakenly assigned to spillover if the experiments are incomplete.

show abstract

“…In physical storage routes, hydrogen compressed under high pressure or stored in a liquid state can achieve attractive volumetric density, but these technologies suffer from extremely harsh processing conditions at a very high cost with severe safety concerns. On the other hand, although hydrogen can be stored in porous materials via adsorption under mild conditions [5][6][7][8][9], the relatively low hydrogen storage capacity of various sorbents seems to be an insurmountable obstacle for practical applications. A great deal of attention has been paid to the chemical storage of hydrogen, and various types of hydrogen storage systems have been intensively studied based on different hydrogen carriers such as metal and organic hydrides [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Catalytic Ammonia Decomposition over High-Performance Ru/Graphene Nanocomposites for Efficient COx-Free Hydrogen Production

Kanezashi

Tsuru

2017

Catalysts

View full text Add to dashboard Cite

Highly-dispersed Ru nanoparticles were grown on graphene nanosheets by simultaneously reducing graphene oxide and Ru ions using ethylene glycol (EG), and the resultant Ru/graphene nanocomposites were applied as a catalyst to ammonia decomposition for CO x -free hydrogen production. Tuning the microstructures of Ru/graphene nanocomposites was easily accomplished in terms of Ru particle size, morphology, and loading by adjusting the preparation conditions. This was the key to excellent catalytic activity, because ammonia decomposition over Ru catalysts is structure-sensitive. Our results demonstrated that Ru/graphene prepared using water as a co-solvent greatly enhanced the catalytic performance for ammonia decomposition, due to the significantly improved nano architectures of the composites. The long-term stability of Ru/graphene catalysts was evaluated for CO x -free hydrogen production from ammonia at high temperatures, and the structural evolution of the catalysts was investigated during the catalytic reactions. Although there were no obvious changes in the catalytic activities at 450 • C over a duration of 80 h, an aggregation of the Ru nanoparticles was still observed in the nanocomposites, which was ascribed mainly to a sintering effect. However, the performance of the Ru/graphene catalyst was decreased gradually at 500 • C within 20 h, which was ascribed mainly to both the effect of the methanation of the graphene nanosheet under a H 2 atmosphere and to enhanced sintering under high temperatures.

show abstract

Effect of Nitrogen Doping on Hydrogen Storage Capacity of Palladium Decorated Graphene

Cited by 284 publications

References 62 publications

Is Spillover Relevant for Hydrogen Adsorption and Storage in Porous Carbons Doped with Palladium Nanoparticles?

Is Spillover Relevant for Hydrogen Adsorption and Storage in Porous Carbons Doped with Palladium Nanoparticles?

Graphene decorated with metal nanoparticles: Hydrogen sorption and related artefacts

Catalytic Ammonia Decomposition over High-Performance Ru/Graphene Nanocomposites for Efficient COx-Free Hydrogen Production

Contact Info

Product

Resources

About