scholarly journals Hydrogen Storage in Untreated/Ammonia-Treated and Transition Metal-Decorated (Pt, Pd, Ni, Rh, Ir and Ru) Activated Carbons

2021 ◽  
Vol 11 (14) ◽  
pp. 6604
Author(s):  
Mohamed F. Aly Aboud ◽  
Zeid A. ALOthman ◽  
Abdulaziz A. Bagabas
Keyword(s):  
Hydrogen Storage ◽  
Activated Carbons ◽  
Spillover Effect ◽  
Hydrogen Uptake ◽  
Hydrogen Spillover ◽  
Average Particle ◽  
Impregnation Method ◽  
Cryogenic Temperatures ◽  
Before And After ◽  
Bottle Neck

Hydrogen storage may be the bottle neck in hydrogen economy, where hydrogen spillover is in dispute as an effective mechanism. In this context, activated carbon (AC) was doped with nitrogen by using ammonia gas, and was further decorated with platinum, palladium, nickel, rhodium, iridium and ruthenium, via an ultrasound-assisted impregnation method, with average particle sizes of around 74, 60, 78, 61, 67 and 38 nm, respectively. The hydrogen storage was compared, before and after modification at both ambient and cryogenic temperatures, for exploring the spillover effect, induced by the decorating transition metals. Ammonia treatment improved hydrogen storage at both 298 K and 77 K, for the samples, where this enhancement was more remarkable at 298 K. Nevertheless, metal decoration reduced the hydrogen uptake of AC for all of the decorated samples other than palladium at cryogenic temperature, but improved it remarkably, especially for iridium and palladium, at room temperature. This observation suggested that metal decoration’s counter effect overcomes hydrogen spillover at cryogenic temperatures, while the opposite takes place at ambient temperature.

scholarly journals A Comparison of Hydrogen Storage in Pt, Pd and Pt/Pd Alloys Loaded Disordered Mesoporous Hollow Carbon Spheres

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 639 ◽  
Author(s):  
Martyna Baca ◽  
Krzysztof Cendrowski ◽  
Wojciech Kukulka ◽  
Grzegorz Bazarko ◽  
Dariusz Moszyński ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Spillover Effect ◽  
Metal Hydrides ◽  
Hydrogen Uptake ◽  
Carbon Spheres ◽  
Ambient Conditions ◽  
Two Factors ◽  
Size Of Particles ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

Comprehensive study to evaluate the ability of hydrogen uptake by disordered mesoporous hollow carbon spheres doped witch metal such as Pt, Pd or Pt/Pd was conducted. They were synthesized facilely using sonication and then calcination process under vacuum at the temperature of 550 °C. The effect on hydrogen sorption at neat-ambient conditions (40 °C, up to 45 bar) was thoroughly analyzed. The results clearly revealed that metal functionalization has a significant impact on the hydrogen storage capacity as the mechanism of gas uptake depends on two factors: metal type and certain size of particles. Thus, functionalized spheres adsorb hydrogen by physisorption forming metal hydrides or metal hydrides combined with hydrogen spillover effect. As a result, a sample with narrower distribution of nanoparticles and smaller specific size exhibited enhanced hydrogen uptake.

scholarly journals Mechanism and Energetics of the Unique Spillover Effect Manifestation, Relevance to the Efficient Hydrogen Storage in Graphite Nanofibers

2015 ◽  
Vol 7 (2) ◽  
pp. 207 ◽  
Author(s):  
Yury Nechaev ◽  
T. Veziroglu
Keyword(s):  
Free Energy ◽  
Hydrogen Storage ◽  
Spillover Effect ◽  
Hydrogen Spillover ◽  
High Density ◽  
Hydrogen Atoms ◽  
Compression Effect ◽  
Graphite Nanofibers ◽  
Hydrogen Molecules ◽  
Thermodynamic Forces

The “thermodynamic forces” and energetics of intercalation of H2 nanophase of a high density into carbon-based nanostructures are considered. The hydrogen self-compression effect, at the expense of the free energy of association of the penetrating hydrogen atoms to the “captured” hydrogen molecules, is shown. The mechanisms of the extraordinary manifestation of both the hydrogen spillover effect, and the Kurdjumov-like effect are discussed.

scholarly journals Application of Experimental Design to Hydrogen Storage: Optimisation of Lignin-Derived Carbons

2019 ◽  
Vol 5 (4) ◽  
pp. 82 ◽  
Author(s):  
Jemma Rowlandson ◽  
James Coombs OBrien ◽  
Karen Edler ◽  
Mi Tian ◽  
Valeska Ting
Keyword(s):  
Hydrogen Storage ◽  
Pore Size ◽  
Surface Area ◽  
Activated Carbons ◽  
Average Pore Size ◽  
High Surface ◽  
Hydrogen Uptake ◽  
Synthesis Process ◽  
Average Pore ◽  
Small Pore

Lignin is a significant by-product of the paper pulping and biofuel industries. Upgrading lignin to a high-value product is essential for the economic viability of biorefineries for bioethanol production and environmentally benign pulping processes. In this work, the feasibility of lignin-derived activated carbons for hydrogen storage was studied using a Design of Experiments methodology, for a time and cost-efficient exploration of the synthesis process. Four factors (carbonisation temperature, activation temperature, carbonisation time, and activation time) were investigated simultaneously. Development of a mathematical model allowed the factors with the greatest impact to be identified using regression analysis for three responses: surface area, average pore size, and hydrogen uptake at 77 K and 1 bar. Maximising the surface area required activation conditions using the highest settings, however, a low carbonisation temperature was also revealed to be integral to prevent detrimental and excessive pore widening. A small pore size, vital for efficient hydrogen uptake, could be achieved by using low carbonisation temperature but also low activation temperatures. An optimum was achieved using the lowest carbonisation conditions (350 °C for 30 min) to retain a smaller pore size, followed by activation under the severest conditions (1000 °C for 60 min) to maximise surface area and hydrogen uptake. These conditions yielded a material with a high surface area of 1400 m2 g−1 and hydrogen uptake of 1.9 wt.% at 77 K and 1 bar.

Hydrogen Spillover Effect of Pt-Doped Activated Carbon Studied by Inelastic Neutron Scattering

2011 ◽  
Vol 2 (18) ◽  
pp. 2322-2325 ◽  
Author(s):  
Cheng-Si Tsao ◽  
Yun Liu ◽  
Haw-Yeu Chuang ◽  
Huan-Hsiung Tseng ◽  
Tsan-Yao Chen ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Spillover Effect ◽  
Inelastic Neutron ◽  
Hydrogen Spillover

scholarly journals Hydrogen uptake of high surface area-activated carbons doped with nitrogen

2013 ◽  
Vol 38 (25) ◽  
pp. 10453-10460 ◽  
Author(s):  
W. Zhao ◽  
V. Fierro ◽  
N. Fernández-Huerta ◽  
M.T. Izquierdo ◽  
A. Celzard
Keyword(s):  
Surface Area ◽  
Activated Carbons ◽  
High Surface ◽  
High Surface Area ◽  
Hydrogen Uptake

Advanced activated carbon monoliths and activated carbons for hydrogen storage

2008 ◽  
Vol 112 (1-3) ◽  
pp. 235-242 ◽  
Author(s):  
María Jordá-Beneyto ◽  
Dolores Lozano-Castelló ◽  
Fabián Suárez-García ◽  
Diego Cazorla-Amorós ◽  
Ángel Linares-Solano
Keyword(s):  
Activated Carbon ◽  
Hydrogen Storage ◽  
Activated Carbons ◽  
Activated Carbon Monoliths

scholarly journals Obtaining the conductive SnO2 films by chemical bath deposition method

2019 ◽  
Vol 60 (11) ◽  
pp. 1-10
Author(s):  
Vladislav I. Rogozin ◽  
◽  
Vyacheslav F. Markov ◽  
Larisa N. Maskaeva ◽  
Anastasia E. Krasovskaya ◽  
...  
Keyword(s):  
Tin Dioxide ◽  
Solid Phase ◽  
Average Particle Size ◽  
Ammonium Fluoride ◽  
Contact Layer ◽  
Average Particle ◽  
Solution Ph ◽  
Before And After ◽  
Initial Salt ◽  
Conductive Properties

Thanks to such unique properties as transparency and conductivity tin dioxide often utilize as transparent contact layer to produce displays, solar cells, and sensor devices. Hydrochemical method of deposition SnO2 films is a perspective due to its simplicity, and economical efficiency. The ionic equilibria analysis was carried out and the boundary conditions of Sn(OH)2 solid phase formation in the «Sn2+ – H2O – OH‾» system calculated. It was established, that tin(II) hydroxide may be obtain in the range 2 < pH < 12. Preliminary results allow to determinate an optimal mixture sourness interval 1 < pH < 5. Revealed, that the thickness of the Sn(OH)2 films strongly depends on the solution pH. Maximum value of 488 nm reached at pH = 8. Conductive SnO2 layers were obtained on a glass and sitall substrates with simultaneously presence of antimony chloride and ammonium fluoride followed by annealing in air. The thickness vs temperature and thickness vs tin initial salt concentration dependences were installed. The uniform tin hydroxide layers with a thickness of ~74 nm may be synthesized under pH = 2 conditions. By the electron microscopy method the average particle size was established changing from 200 to 400 nm for as-synthesized films, to ~20 nm for annealed which indicates the nanostructure nature of the films. The morphology, elemental composition and conductive properties of deposited films were investigated before and after heating stage. Studying the annealing temperature influence at the film resistance were identified a three temperature ranges within which the films sharply differ in their conductive properties, which is associated with phase and structural transformations in them. Shown, that the most conductive SnO2 films with the omic resistance 3-5 kOm/sm were obtained at the temperature range 620-870 K.

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