scholarly journals Enhanced heterogenous hydration of SO 2 through immobilization of pyridinic-N on carbon materials

2020 ◽  
Vol 7 (8) ◽  
pp. 192248
Author(s):  
Longhua Zou ◽  
Ping Yan ◽  
Peng Lu ◽  
Dongyao Chen ◽  
Wei Chu ◽  
...  
Keyword(s):  
Gas Phase ◽  
Energy Barrier ◽  
Carbon Materials ◽  
Water Concentration ◽  
Flue Gases ◽  
Doped Graphene ◽  
Molecular Dynamics Results ◽  
Pyridinic N ◽  
Pyridinic Nitrogen

Carbon materials doped with nitrogen have long been used for SO 2 removal from flue gases for the benefits of the environment. The role of water is generally regarded as hydration of SO 3 which is formed through the oxidization of SO 2 . However, the hydration of SO 2 , especially on the surface of N-doped carbon materials, was almost ignored. In this study, the hydration of SO 2 was investigated in detail on the pyridinic nitrogen (PyN)-doped graphene (GP) surfaces. It is found that, compared with the homogeneous hydration of SO 2 assisted with NH 3 in gas phase, the heterogeneous hydration is much more thermodynamically and kinetically favourable. Specifically, when a single H 2 O molecule is involved, the energy barrier for SO 2 hydration is as low as 0.15 eV, with 0.59 eV released, indicating the hydration of SO 2 can occur at rather low water concentration and temperature. Thermodynamic integration molecular dynamics results show the feasibility of the hydrogenated substrate recovery and the immobilized N acting as a catalytic site for SO 2 hydration. Our findings show that the heterogeneous hydration of SO 2 should be universal and potentially uncover the puzzling reaction mechanism for SO 2 catalytic oxidation at low temperature by N-doped carbon materials.

scholarly journals Chemical Vapor Deposition of N-Doped Graphene and Carbon Films: The Role of Precursors and Gas Phase

ACS Nano ◽  
2014 ◽  
Vol 8 (4) ◽  
pp. 3337-3346 ◽  
Author(s):  
Yoshikazu Ito ◽  
Christos Christodoulou ◽  
Marco Vittorio Nardi ◽  
Norbert Koch ◽  
Hermann Sachdev ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Doped Graphene

Role of Pyridinic-N for Nitrogen-doped graphene quantum dots in oxygen reaction reduction

2017 ◽  
Vol 508 ◽  
pp. 154-158 ◽  
Author(s):  
Lang Sun ◽  
Yi Luo ◽  
Ming Li ◽  
Guanghui Hu ◽  
Yongjie Xu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
Pyridinic N ◽  
Oxygen Reaction

Liquid versus gas phase dehydrogenation of formic acid over Co@N-doped carbon materials. The role of single atomic sites

2021 ◽  
Vol 504 ◽  
pp. 111457
Author(s):  
Aleksey N. Chernov ◽  
Tatiana V. Astrakova ◽  
Vladimir I. Sobolev ◽  
Konstantin Yu. Koltunov
Keyword(s):  
Formic Acid ◽  
Gas Phase ◽  
Carbon Materials

Application of Disk Aerators to Recarbonation of Alkaline Wastewater from Wet Gasification of Carbide

1991 ◽  
Vol 24 (7) ◽  
pp. 277-284 ◽  
Author(s):  
E. Gomólka ◽  
B. Gomólka
Keyword(s):  
Carbon Dioxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Flue Gas ◽  
Carbonic Acid ◽  
Low Cost ◽  
Flue Gases ◽  
Carbon Dioxide Content ◽  
Patent Claim ◽  
Phase Dispersion

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.

Pyridinic nitrogen exclusively doped carbon materials as efficient oxygen reduction electrocatalysts for Zn-air batteries

2020 ◽  
Vol 261 ◽  
pp. 118234 ◽  
Author(s):  
Qing Lv ◽  
Ning Wang ◽  
Wenyan Si ◽  
Zhufeng Hou ◽  
Xiaodong Li ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Carbon Materials ◽  
Pyridinic Nitrogen

scholarly journals Effect of the number of nitrogen dopants on the electronic and magnetic properties of graphitic and pyridinic N-doped graphene – a density-functional study

RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18371-18380
Author(s):  
Erik Bhekti Yutomo ◽  
Fatimah Arofiati Noor ◽  
Toto Winata
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Functional Study ◽  
Density Functional Study ◽  
Electronic And Magnetic Properties ◽  
Doped Graphene ◽  
Dopant Atoms ◽  
Pyridinic N

The number of dopant atoms is a parameter that can effectively tune the electronic and magnetic properties of graphitic and pyridinic N-doped graphene.

scholarly journals The role of radiolysis in the modelling of C2H4O2 isomers and dimethyl ether in cold dark clouds

2020 ◽  
Vol 500 (3) ◽  
pp. 3414-3424
Author(s):  
Alec Paulive ◽  
Christopher N Shingledecker ◽  
Eric Herbst
Keyword(s):  
Gas Phase ◽  
Dimethyl Ether ◽  
Recent Observation ◽  
Cosmic Ray ◽  
Thermal Method ◽  
Dark Clouds ◽  
Ice Surface ◽  
Dust Grain ◽  
Complex Organic

ABSTRACT Complex organic molecules (COMs) have been detected in a variety of interstellar sources. The abundances of these COMs in warming sources can be explained by syntheses linked to increasing temperatures and densities, allowing quasi-thermal chemical reactions to occur rapidly enough to produce observable amounts of COMs, both in the gas phase, and upon dust grain ice mantles. The COMs produced on grains then become gaseous as the temperature increases sufficiently to allow their thermal desorption. The recent observation of gaseous COMs in cold sources has not been fully explained by these gas-phase and dust grain production routes. Radiolysis chemistry is a possible non-thermal method of producing COMs in cold dark clouds. This new method greatly increases the modelled abundance of selected COMs upon the ice surface and within the ice mantle due to excitation and ionization events from cosmic ray bombardment. We examine the effect of radiolysis on three C2H4O2 isomers – methyl formate (HCOOCH3), glycolaldehyde (HCOCH2OH), and acetic acid (CH3COOH) – and a chemically similar molecule, dimethyl ether (CH3OCH3), in cold dark clouds. We then compare our modelled gaseous abundances with observed abundances in TMC-1, L1689B, and B1-b.

scholarly journals The Activating Effect of Strong Acid for Pd-Catalyzed Directed C–H Activation by Concerted Metalation-Deprotonation Mechanism

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4083
Author(s):  
Heming Jiang ◽  
Tian-Yu Sun
Keyword(s):  
Activation Energy ◽  
Dft Calculations ◽  
Energy Barrier ◽  
Computational Study ◽  
Strong Acid ◽  
Activation Energy Barrier ◽  
Pd Catalysts ◽  
Acid Ligand ◽  
Strong Acids

A computational study on the origin of the activating effect for Pd-catalyzed directed C–H activation by the concerted metalation-deprotonation (CMD) mechanism is conducted. DFT calculations indicate that strong acids can make Pd catalysts coordinate with directing groups (DGs) of the substrates more strongly and lower the C–H activation energy barrier. For the CMD mechanism, the electrophilicity of the Pd center and the basicity of the corresponding acid ligand for deprotonating the C–H bond are vital to the overall C–H activation energy barrier. Furthermore, this rule might disclose the role of some additives for C–H activation.

scholarly journals Theoretical Study on the Photo-Oxidation and Photoreduction of an Azetidine Derivative as a Model of DNA Repair

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2911
Author(s):  
Miriam Navarrete-Miguel ◽  
Antonio Francés-Monerris ◽  
Miguel A. Miranda ◽  
Virginie Lhiaubet-Vallet ◽  
Daniel Roca-Sanjuán
Keyword(s):  
Electron Transfer ◽  
Energy Barrier ◽  
Ring Opening ◽  
Dna Lesions ◽  
Barrier Heights ◽  
Dna Lesion ◽  
Electron Reduction ◽  
The Stability ◽  
Electron Transfer Processes

Photocycloreversion plays a central role in the study of the repair of DNA lesions, reverting them into the original pyrimidine nucleobases. Particularly, among the proposed mechanisms for the repair of DNA (6-4) photoproducts by photolyases, it has been suggested that it takes place through an intermediate characterized by a four-membered heterocyclic oxetane or azetidine ring, whose opening requires the reduction of the fused nucleobases. The specific role of this electron transfer step and its impact on the ring opening energetics remain to be understood. These processes are studied herein by means of quantum-chemical calculations on the two azetidine stereoisomers obtained from photocycloaddition between 6-azauracil and cyclohexene. First, we analyze the efficiency of the electron-transfer processes by computing the redox properties of the azetidine isomers as well as those of a series of aromatic photosensitizers acting as photoreductants and photo-oxidants. We find certain stereodifferentiation favoring oxidation of the cis-isomer, in agreement with previous experimental data. Second, we determine the reaction profiles of the ring-opening mechanism of the cationic, neutral, and anionic systems and assess their feasibility based on their energy barrier heights and the stability of the reactants and products. Results show that oxidation largely decreases the ring-opening energy barrier for both stereoisomers, even though the process is forecast as too slow to be competitive. Conversely, one-electron reduction dramatically facilitates the ring opening of the azetidine heterocycle. Considering the overall quantum-chemistry findings, N,N-dimethylaniline is proposed as an efficient photosensitizer to trigger the photoinduced cycloreversion of the DNA lesion model.

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