scholarly journals Carbon Nitride Nanotube as a Chemical Sensor for Melamine: A Theoretical Study

2017 ◽  
Vol 60 (4) ◽  
Author(s):  
Reza Moradi ◽  
Javad Hosseini Hosseini
Keyword(s):  
Density Functional ◽  
Carbon Nitride ◽  
Adsorption Process ◽  
Chemical Sensor ◽  
Theoretical Study ◽  
Tube Wall ◽  
High Sensitivity ◽  
Tube Surface ◽  
Promising Candidate ◽  
Short Recovery Time

The interaction of a melamine molecule with a carbon nitride nanotube (CNNT) was explored by means of dispersion-corrected density functional calculations. It was found that melamine prefers to be adsorbed on the porous site of the tube wall with the adsorption energy of -21.9 kcal/mol. This adsorption process significantly shifts the HOMO of the tube to higher energies, thereby reducing the gap of the tube from 3.97 to 2.65 eV. Moreover, the work function is slightly decreased which can facilitate the field electron emission from the tube surface. It is expected that CNNT can be a promising candidate for sensor devices in detecting the melamine molecule with short recovery time and high sensitivity.

Ru-decorated gallium nitride nanotubes as chemical sensor for detection of purinethol drug: a density functional theory study

2021 ◽  
Author(s):  
A. A. Menazea ◽  
Nasser S. Awwad ◽  
Hala Ibrahium ◽  
Parvaneh delirkheirollahinezhad ◽  
H. Elhosiny Ali
Keyword(s):  
Recovery Time ◽  
Density Functional ◽  
Chemical Sensor ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Water Solvent ◽  
Highly Sensitive ◽  
Short Recovery Time ◽  
The Impact ◽  
Sensing Performance

Abstract We employed density functional B3LYP to inspect the impact of Ru-decoration on a GaN nanotube (GaNNT) sensing performance in detection of purinethol (PT) drug. The interaction of the pristine GaNNT with the PT was found to be weak, and the sensing response is 4.3. Decorating an Ru atom into the GaNNT surface increases the adsorption energy (Ead) of PT from -6.5 to -23.6 kcal/mol. The sensing response significantly rises to 93.6 by Ru-decoration. A short recovery time of 15.7 s is found for the PT desorption from the Ru-decorated GaNNT surface at 298 K. The water solvent reduces Ead of PT to -20.1 kcal/mol. Thus, it suggests that Ru-decorated GaNNT may be a highly sensitive PT sensor with a short recovery time.

scholarly journals Ni-CNT Chemical Sensor for SF6 Decomposition Components Detection: A Combined Experimental and Theoretical Study

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3493 ◽  
Author(s):  
Yingang Gui ◽  
Xiaoxing Zhang ◽  
Peigeng Lv ◽  
Shan Wang ◽  
Chao Tang ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Density Functional ◽  
Chemical Sensor ◽  
Theoretical Study ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Gas Sensitivity ◽  
Sensitivity And Selectivity ◽  
Sf6 Decomposition ◽  
Insulation Status

SF6 decomposition components detection is a key technology to evaluate and diagnose the insulation status of SF6-insulated equipment online, especially when insulation defects-induced discharge occurs in equipment. In order to detect the type and concentration of SF6 decomposition components, a Ni-modified carbon nanotube (Ni-CNT) gas sensor has been prepared to analyze its gas sensitivity and selectivity to SF6 decomposition components based on an experimental and density functional theory (DFT) theoretical study. Experimental results show that a Ni-CNT gas sensor presents an outstanding gas sensing property according to the significant change of conductivity during the gas molecule adsorption. The conductivity increases in the following order: H2S > SOF2 > SO2 > SO2F2. The limit of detection of the Ni-CNT gas sensor reaches 1 ppm. In addition, the excellent recovery property of the Ni-CNT gas sensor makes it easy to be widely used. A DFT theoretical study was applied to analyze the influence mechanism of Ni modification on SF6 decomposition components detection. In summary, the Ni-CNT gas sensor prepared in this study can be an effective way to evaluate and diagnose the insulation status of SF6-insulated equipment online.

A strategy for enhancing the photoactivity of g-C3N4-based single-atom catalysts via sulphur doping: a theoretical study

2021 ◽  
Vol 23 (11) ◽  
pp. 6632-6640
Author(s):  
Yanqing Guo ◽  
Meng Xia ◽  
Mingkun Zhang ◽  
Jing Zou ◽  
Yue You ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Photocatalytic Activity ◽  
Density Functional ◽  
Carbon Nitride ◽  
Theoretical Study ◽  
Density Functional Theory Calculations ◽  
Graphitic Carbon Nitride ◽  
Single Atom ◽  
Functional Theory ◽  
The Density Functional Theory

The sulphur-doping strategy was proposed to enhance the incorporation of single Pt atoms in monolayer graphitic carbon nitride and the density functional theory calculations verified it has superb photocatalytic activity.

scholarly journals A theoretical study on the CO2 methanation over Ni5/AC catalysts by means of density functional theory. Part I: Adsorption and activation stages

2020 ◽  
Vol 9 (1) ◽  
pp. 33-38
Author(s):  
Hue Van Thi Minh ◽  
Lan Phung Thi ◽  
Ha Nguyen Thi Thu ◽  
Cam Le Minh ◽  
Ha Nguyen Ngoc
Keyword(s):  
Density Functional Theory ◽  
Activated Carbon ◽  
Adsorption Energy ◽  
Density Functional ◽  
Adsorption Process ◽  
Theoretical Study ◽  
Bond Orders ◽  
Elastic Band ◽  
Co2 Methanation ◽  
Functional Theory

The adsorption and activation processes of CO2 and H2 on Ni5 catalyst supported on activated carbon (Ni5/AC) were investigated by using density functional theory at GGA-PBE/DZP level of theory and climbing image – nudged elastic band (CI-NEB) method. The adsorption energy, charges on atoms, bond orders and geometry parameters were calculated and analyzed. The most favourable adsorption configurations were determined. The results show that H2 and CO2 are chemically adsorbed on Ni5/AC. The adsorption process does not involved a transition state. CO2 is strongly activated on Ni5/AC system.

scholarly journals A Theoretical Study on the Hydrogenation of CO Over Co2Cu2 Bimetallic Catalyst Supported on MgO(200) by Means of Density Functional Theory Part 1: Adsorption and Activation Stages

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Nguyen Binh Long ◽  
Nguyen Thi Thu Ha ◽  
Phung Thi Lan ◽  
Le Minh Cam ◽  
Nguyen Ngoc Ha
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Adsorption Process ◽  
Theoretical Study ◽  
Bimetallic Catalyst ◽  
Functional Theory ◽  
Initial Cluster ◽  
Mgo Support ◽  
Adsorption Processes ◽  
Hydrogenation Of Co

Density functional theory (DFT) at GGA-PBE/DZP level was performed to study the adsorption processes of CO and H2 on clusters Co2Cu2 and Co2Cu2 supported on MgO (Co2Cu2/MgO) system. The electronic structures, geometries of Co2Cu2 and Co2Cu2/MgO, adsorption energies were studied and analyzed. The optimal adsorption configurations of CO and H2 on Co2Cu2 and Co2Cu2/MgO were determined. The results show that CO and H2 are chemically adsorbed on Co2Cu2 and Co2Cu2/MgO systems and the adsorption process does not involve a transition state. MgO support plays important role in the increasing of the activation ability of Co2Cu2/MgO for CO compared to the initial cluster. Keywords: Syngas, DFT, Co2Cu2, MgO, adsorption.  

scholarly journals A theoretical study on the adsorption of dichlorodiphenyltrichloroethane (DDT) on graphitic carbon nitride (g-C3N4) and g-C3N4 modified with cluster Ni2

2021 ◽  
Vol 10 (3) ◽  
pp. 58-64
Author(s):  
Be Pham Thi ◽  
Ha Nguyen Thi Thu ◽  
Ha Nguyen Ngoc
Keyword(s):  
Carbon Nitride ◽  
Adsorption Process ◽  
Theoretical Study ◽  
Tight Binding ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Bond Orders ◽  
Adsorption Ability ◽  
Enhanced Adsorption ◽  
Nickel Cluster

A robust and accurate tight-binding quantum chemical method was performed to study adsorption process of dichlorodiphenyltrichloroethane (DDT) on graphitic carbon nitride (g-C3N4) and  g-C3N4 modified with nickel cluster (Ni2). The adsorption energy, charges on atoms, bond orders have been calculated and analysed. The obtained results indicate that the adsorption of DDT on the pristine g-C3N4 is physical of nature. Ni2 cluster can be easily doped on g-C3N4 due to the formation of chemical bonds. The Ni2-g-C3N4 system exhibits enhanced adsorption ability for DDT.

scholarly journals Adsorption of lindane (γ-hexachlorocyclohexane) on nickel modified graphitic carbon nitride: a theoretical study

RSC Advances ◽  
2021 ◽  
Vol 11 (34) ◽  
pp. 21048-21056
Author(s):  
Nguyen Thi Thu Ha ◽  
Pham Thi Be ◽  
Nguyen Ngoc Ha
Keyword(s):  
Carbon Nitride ◽  
Adsorption Process ◽  
Theoretical Study ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Material Thickness

A comprehensive theoretical study on the adsorption of lindane on nickel modified g-C3N4 was performed. The influence of material thickness, different solvents and temperature on the adsorption process was discussed and analyzed in detail.

Computationally Assisted Design of High Signal-to-Noise Photoinduced Electron Transfer-Based Voltage-Sensitive Dyes

2020 ◽  
Author(s):  
Rishikesh Kulkarni ◽  
Anneliese Gest ◽  
Chun Kei Lam ◽  
Benjamin Raliski ◽  
Feroz James ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dft Calculations ◽  
Photoinduced Electron Transfer ◽  
Density Functional ◽  
Embryonic Stem ◽  
High Sensitivity ◽  
Md Simulations ◽  
High Signal ◽  
Signal To Noise ◽  
Green Fluorescent

<p>High signal-to-noise optical voltage indicators will enable simultaneous interrogation of membrane potential in large ensembles of neurons. However, design principles for voltage sensors with high sensitivity and brightness remain elusive, limiting the applicability of voltage imaging. In this paper, we use molecular dynamics (MD) simulations and density functional theory (DFT) calculations to guide the design of a bright and sensitive green-fluorescent voltage-sensitive fluorophore, or VoltageFluor (VF dye), that uses photoinduced electron transfer (PeT) as a voltage-sensing mechanism. MD simulations predict an 11% increase in sensitivity due to membrane orientation, while DFT calculations predict an increase in fluorescence quantum yield, but a decrease in sensitivity due to a decrease in rate of PeT. We confirm these predictions by synthesizing a new VF dye and demonstrating that it displays the expected improvements by doubling the brightness and retaining similar sensitivity to prior VF dyes. Combining theoretical predictions and experimental validation has resulted in the synthesis of the highest signal-to-noise green VF dye to date. We use this new voltage indicator to monitor the electrophysiological maturation of human embryonic stem cell-derived medium spiny neurons. </p>

scholarly journals Theoretical Study of Zirconium Isomorphous Substitution into Zeolite Frameworks

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4466
Author(s):  
Duichun Li ◽  
Bin Xing ◽  
Baojun Wang ◽  
Ruifeng Li
Keyword(s):  
Acid Site ◽  
Density Functional ◽  
Theoretical Study ◽  
Atomic Radius ◽  
Acid Sites ◽  
Isomorphous Substitution ◽  
Dispersion Correction ◽  
Brønsted Acidity ◽  
Functional Theory ◽  
Brönsted Acidity

Systematic periodic density functional theory computations including dispersion correction (DFT-D) were carried out to determine the preferred location site of Zr atoms in sodalite (SOD) and CHA-type topology frameworks, including alumino-phosphate-34 (AlPO-34) and silico-alumino-phosphate-34 (SAPO-34), and to determine the relative stability and Brönsted acidity of Zr-substituted forms of SOD, AlPO-34, and SAPO-34. Mono and multiple Zr atom substitutions were considered. The Zr substitution causes obvious structural distortion because of the larger atomic radius of Zr than that of Si, however, Zr-substituted forms of zeolites are found to be more stable than pristine zeolites. Our results demonstrate that in the most stable configurations, the preferred favorable substitutions of Zr in substituted SOD have Zr located at the neighboring sites of the Al-substituted site. However, in the AlPO-34 and SAPO-34 frameworks, the Zr atoms are more easily distributed in a dispersed form, rather than being centralized. Brönsted acidity of substituted zeolites strongly depends on Zr content. For SOD, substitution of Zr atoms reduces Brönsted acidity. However, for Zr-substituted forms of AlPO-34 and SAPO-34, Brönsted acidity of the Zr-O(H)-Al acid sites are, at first, reduced and, then, the presence of Zr atoms substantially increased Brönsted acidity of the Zr-O(H)-Al acid site. The results in the SAPO-34-Zr indicate that more Zr atoms substantially increase Brönsted acidity of the Si-O(H)-Al acid site. It is suggested that substituted heteroatoms play an important role in regulating and controlling structural stability and Brönsted acidity of zeolites.

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