scholarly journals Atomistic Modeling of Gas Adsorption in Nanocarbons

2012 ◽  
Vol 2012 ◽  
pp. 1-32 ◽  
Author(s):  
G. Zollo ◽  
F. Gala
Keyword(s):  
Gas Sensors ◽  
Significant Variation ◽  
Carbon Nanostructures ◽  
Scientific Literature ◽  
Gas Adsorption ◽  
Hydrogen Adsorption ◽  
Atomistic Simulations ◽  
Atomistic Modeling ◽  
Theoretical Frameworks ◽  
Different Characteristics

Carbon nanostructures are currently under investigation as possible ideal media for gas storage and mesoporous materials for gas sensors. The recent scientific literature concerning gas adsorption in nanocarbons, however, is affected by a significant variation in the experimental data, mainly due to the different characteristics of the investigated samples arising from the variety of the synthesis techniques used and their reproducibility. Atomistic simulations have turned out to be sometimes crucial to study the properties of these systems in order to support the experiments, to indicate the physical limits inherent in the investigated structures, and to suggest possible new routes for application purposes. In consideration of the extent of the theme, we have chosen to treat in this paper the results obtained within some of the most popular atomistic theoretical frameworks without any purpose of completeness. A significant part of this paper is dedicated to the hydrogen adsorption on C-based nanostructures for its obvious importance and the exceptional efforts devoted to it by the scientific community.

scholarly journals Behavioural Study of the Force Control Loop Used in a Collaborative Robot for Sanding Materials

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 67
Author(s):  
Rodrigo Pérez Ubeda ◽  
Santiago C. Gutiérrez Rubert ◽  
Ranko Zotovic Stanisic ◽  
Ángel Perles Ivars
Keyword(s):  
Force Control ◽  
Feed Rate ◽  
Significant Variation ◽  
Industrial Robots ◽  
Control Loop ◽  
Saturation State ◽  
Collaborative Robots ◽  
Increase Productivity ◽  
Different Characteristics ◽  
Collaborative Robot

The rise of collaborative robots urges the consideration of them for different industrial tasks such as sanding. In this context, the purpose of this article is to demonstrate the feasibility of using collaborative robots in processing operations, such as orbital sanding. For the demonstration, the tools and working conditions have been adjusted to the capacity of the robot. Materials with different characteristics have been selected, such as aluminium, steel, brass, wood, and plastic. An inner/outer control loop strategy has been used, complementing the robot’s motion control with an outer force control loop. After carrying out an explanatory design of experiments, it was observed that it is possible to perform the operation in all materials, without destabilising the control, with a mean force error of 0.32%. Compared with industrial robots, collaborative ones can perform the same sanding task with similar results. An important outcome is that unlike what might be thought, an increase in the applied force does not guarantee a better finish. In fact, an increase in the feed rate does not produce significant variation in the finish—less than 0.02 µm; therefore, the process is in a “saturation state” and it is possible to increase the feed rate to increase productivity.

ELECTROCHEMICAL STORAGE OF HYDROGEN IN CARBON NANOSTRUCTURES

2003 ◽  
Vol 02 (04n05) ◽  
pp. 307-317
Author(s):  
M. S. YU ◽  
S. Y. CHENG ◽  
Y. C. LIN ◽  
W. C. HO
Keyword(s):  
Carbon Nanostructures ◽  
Room Temperature ◽  
Hydrogen Adsorption ◽  
Abundance Ratio ◽  
Nanostructured Carbon ◽  
Half Cell ◽  
Carbonaceous Particles ◽  
Catalytic Thermal Decomposition ◽  
Electrochemical Storage ◽  
Preliminary Study

We have synthesized a set of nanostructured carbon samples including a variety of carbon nanotubes and carbonaceous particles, by catalytic thermal decomposition of CH4 on catalyst LaNi 5 powder with different reaction temperatures. Products obtained at reaction temperatures 550~900°C were characterized by means of HR-TEM, SEM and Raman Scattering. In addition, electrochemical charge–discharge cycling method was carried out at room temperature to measure the reversible hydrogen capacity in pressed electrodes containing mixture of catalyst, nanostructured carbon samples and carbonaceous particles. Results showed that the abundance ratio of well-crystallized graphite to amorphous carbon in each product increases with increasing reaction temperatures. This preliminary study showed also that the hydrogen storage capacity of synthesis products measured in an electrochemical half-cell at room temperature correlates with the nanostructure and morphology of the variety of nanostructured carbon samples. Additionally, the hydrogen adsorption capacity against specific surface area (BET) for synthesis products produced at temperatures higher than 670°C is ranging from 14 to 25 wt.%/(1000 m2/g).

Study on adsorption of CO and CO2 by graphene gas sensor

2021 ◽  
pp. 2150154
Author(s):  
Wenchao Tian ◽  
Jiahao Niu ◽  
Wenhua Li ◽  
Xiaohan Liu
Keyword(s):  
Gas Sensors ◽  
Active Sites ◽  
Density Functional ◽  
Gas Adsorption ◽  
Experimental Studies ◽  
Detection Accuracy ◽  
Functional Theory ◽  
Vacancy Defects ◽  
Adsorption Of Co ◽  
Detection Characteristics

The two-dimensional (2D) plane of graphene has many active sites for gas adsorption. It has broad application prospects in the field of MEMS gas sensors. At present, there are many experimental studies on graphene gas sensors, but it is difficult to accurately control various influencing factors in the experiments. Therefore, this paper applies the first principle based on density functional theory to study the adsorption and detection characteristics of graphene on CO and CO2. The first-principles analysis method was used to study the adsorption characteristics and sensitivity of graphene. The results show that the inductive graphene has a sensitivity of 1.55% and 0.77% for CO and CO2, respectively. The Stone–Wales defects and multi-vacancy defects have greatly improved the sensitivity of graphene to CO, which is 35.25% and 4.14%, respectively. Introduction of defects increases the sensitivity of detection of CO and CO2, but also improves the selective gas detection material of these two gases. Thus, the control and selectively introducing defects may improve the detection accuracy of the graphene CO and CO2.

scholarly journals A computational approach towards understanding hydrogen gas adsorption in Co–MIL-88A

RSC Advances ◽  
2017 ◽  
Vol 7 (63) ◽  
pp. 39583-39593 ◽  
Author(s):  
Nguyen Thi Xuan Huynh ◽  
O My Na ◽  
Viorel Chihaia ◽  
Do Ngoc Son
Keyword(s):  
Gas Adsorption ◽  
Hydrogen Adsorption ◽  
Computational Approach ◽  
Hydrogen Gas ◽  
Hollow Site

The hydrogen adsorption is most favorable at the hollow site of Co–MIL-88A.

Pressure Isotherms of Hydrogen Adsorption in Carbon Nanostructures

2001 ◽  
Vol 706 ◽  
Author(s):  
Xiaohong Chen ◽  
Urszula Dettlaff-Weglikowska ◽  
Miroslav Haluska ◽  
Martin Hulman ◽  
Siegmar Roth ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Activated Carbon ◽  
Hydrogen Storage ◽  
Carbon Nanostructures ◽  
Room Temperature ◽  
Storage Capacity ◽  
Hydrogen Adsorption ◽  
Single Wall Carbon Nanotubes ◽  
Hydrogen Storage Capacity ◽  
Carbon And Graphite

AbstractThe hydrogen adsorption capacity of various carbon nanostructures including single-wall carbon nanotubes, graphitic nanofibers, activated carbon, and graphite has been measured as a function of pressure and temperature. Our results show that at room temperature and a pressure of 80 bar the hydrogen storage capacity is less than 1 wt.% for all samples. Upon cooling, the capacity of hydrogen adsorption increases with decreasing temperature and the highest value was observed to be 2.9 wt. % at 50 bar and 77 K. The correlation between hydrogen storage capacity and specific surface area is discussed.

scholarly journals The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

2021 ◽  
Author(s):  
Victor Kwan ◽  
Ryan O'Dwyer ◽  
David Laur ◽  
Jiahua Tan ◽  
Styliani Consta
Keyword(s):  
Chemical Reactivity ◽  
Double Electric Layer ◽  
Atomistic Simulations ◽  
Excess Charge ◽  
Atomistic Modeling ◽  
Ion Distribution ◽  
Equilibrium Partition ◽  
Equilibrium Process ◽  
Ejection Mechanism ◽  
Ion Evaporation

The composition of outer drop layers has been associated with distinct chemical reactivity. We use atomistic modeling to examine how the composition of the surface excess charge layer (SECL) is related to the ejection mechanisms of ions. Even though the drop disintegration is inherently a non-equilibrium process we find that the equilibrium ion distribution in SECL predicts the ions that are ejected. The escape of the ions in aqueous drops takes place from conical protrusions that are global drop deformations and their appearance is independent of the location of a single ion. Our results are consistent with the equilibrium partition model, which associates the mass spectrum with the distribution of analytes in the drop’s double electric layer. We present evidence that atomistic simulations of minute nano-drops cannot distinguish Rayleigh fission from the ion evaporation mechanism.

scholarly journals The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

2021 ◽  
Author(s):  
Victor Kwan ◽  
Ryan O'Dwyer ◽  
David Laur ◽  
Jiahua Tan ◽  
Styliani Consta
Keyword(s):  
Chemical Reactivity ◽  
Double Electric Layer ◽  
Atomistic Simulations ◽  
Excess Charge ◽  
Atomistic Modeling ◽  
Ion Distribution ◽  
Equilibrium Partition ◽  
Equilibrium Process ◽  
Ejection Mechanism ◽  
Ion Evaporation

The composition of outer drop layers has been associated with distinct chemical reactivity. We use atomistic modeling to examine how the composition of the surface excess charge layer (SECL) is related to the ejection mechanisms of ions. Even though the drop disintegration is inherently a non-equilibrium process we find that the equilibrium ion distribution in SECL predicts the ions that are ejected. The escape of the ions in aqueous drops takes place from conical protrusions that are global drop deformations and their appearance is independent of the location of a single ion. Our results agree with the equilibrium partition model, which associates the mass spectrum with the distribution of analytes in the drop’s double electric layer. We present evidence that atomistic simulations of minute nano-drops cannot distinguish Rayleigh fission from the ion evaporation mechanism.

scholarly journals The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

2021 ◽  
Author(s):  
Victor Kwan ◽  
Ryan O'Dwyer ◽  
David Laur ◽  
Jiahua Tan ◽  
Styliani Consta
Keyword(s):  
Chemical Reactivity ◽  
Double Electric Layer ◽  
Atomistic Simulations ◽  
Excess Charge ◽  
Atomistic Modeling ◽  
Ion Distribution ◽  
Equilibrium Partition ◽  
Equilibrium Process ◽  
Ejection Mechanism ◽  
Ion Evaporation

The composition of outer drop layers has been associated with distinct chemical reactivity. We use atomistic modeling to examine how the composition of the surface excess charge layer (SECL) is related to the ejection mechanisms of ions. Even though the drop disintegration is inherently a non-equilibrium process we find that the equilibrium ion distribution in SECL predicts the ions that are ejected. The escape of the ions in aqueous drops takes place from conical protrusions that are global drop deformations and their appearance is independent of the location of a single ion. Our results are consistent with the equilibrium partition model, which associates the mass spectrum with the distribution of analytes in the drop’s double electric layer. We present evidence that atomistic simulations of minute nano-drops cannot distinguish Rayleigh fission from the ion evaporation mechanism.

Intriguing differences in hydrogen adsorption in CPO-27 materials induced by metal substitution

2015 ◽  
Vol 3 (9) ◽  
pp. 4827-4839 ◽  
Author(s):  
Mali H. Rosnes ◽  
Martin Opitz ◽  
Matthias Frontzek ◽  
Wiebke Lohstroh ◽  
Jan Peter Embs ◽  
...  
Keyword(s):  
Comparative Study ◽  
Gas Adsorption ◽  
Hydrogen Adsorption ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Hydrogen Gas ◽  
The Other ◽  
Metal Substitution ◽  
Isosteric Heat Of Adsorption ◽  
Open Metal Sites

We present a comparative study of hydrogen gas adsorption experiments on CPO-27–Cu and –Mn. The initial isosteric heat of adsorption in CPO-27–Cu is low for a material containing open metal sites and in contrast to the other members of the CPO-27 series, including the Mn compound.

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