scholarly journals Theoretical Study of As2O3 Adsorption Mechanisms on CaO surface

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 677 ◽  
Author(s):  
Yaming Fan ◽  
Qiyu Weng ◽  
Yuqun Zhuo ◽  
Songtao Dong ◽  
Pengbo Hu ◽  
...  

Emission of hazardous trace elements, especially arsenic from fossil fuel combustion, have become a major concern. Under an oxidizing atmosphere, most of the arsenic converts to gaseous As2O3. CaO has been proven effective in capturing As2O3. In this study, the mechanisms of As2O3 adsorption on CaO surface under O2 atmosphere were investigated by density functional theory (DFT) calculation. Stable physisorption and chemisorption structures and related reaction paths are determined; arsenite (AsO33−) is proven to be the form of adsorption products. Under the O2 atmosphere, the adsorption product is arsenate (AsO43−), while tricalcium orthoarsenate (Ca3As2O8) and dicalcium pyroarsenate (Ca2As2O7) are formed according to different adsorption structures.

Author(s):  
Mahnaz Fatima

Abstract: In this paper we worked on a theoretical study of Ethylene glycol and styrene glycol Which is based on density functional theory, implement in computational program SIESTA with use of general gradient approximation (GGA) of Perdew, Burke and Emzerhof (PBE) scheme for an account of exchange co-relation effect to obtain density of state , projected density of state and charge density. Keywords: Density functional theory, SIESTA, Density of state .Projected density of state ,charge density .


2020 ◽  
Vol 22 (8) ◽  
pp. 4549-4560 ◽  
Author(s):  
Lixia Ling ◽  
Yueting Cao ◽  
Min Han ◽  
Ping Liu ◽  
Riguang Zhang ◽  
...  

The formation of dimethyl oxalate (DMO) via CO catalytic coupling on a series of catalysts including Pdn (n = 1, 2, 3, 4 and 6) clusters loaded on TiO2-V has been explored by density functional theory (DFT) calculation.


2021 ◽  
Vol 23 (37) ◽  
pp. 21078-21086
Author(s):  
Tomomi Shimazaki ◽  
Masanori Tachikawa

In this work, the excitation energies of asymmetric thiazolothizaole (TTz) dye molecules have been theoretically studied using dielectric-dependent density functional theory (DFT).


RSC Advances ◽  
2018 ◽  
Vol 8 (27) ◽  
pp. 15196-15201 ◽  
Author(s):  
Xiang-Yun Wang ◽  
Hui-Min Yan ◽  
Yan-Li Han ◽  
Zhu-Xia Zhang ◽  
Xiao-Yun Zhang ◽  
...  

Density functional theory calculations were performed in order to reveal the mysterious catalytic step of the biosynthesis of estrogens.


2020 ◽  
Vol 12 (02) ◽  
pp. 99-111
Author(s):  
Jamal A. Shlaka ◽  
◽  
Abbas H. Abo Nasria

Been studying the interactions between graphene - like aluminium nitride P(AlN)21 nano ribbons doped and defect (AlN)21Sheet, Molecules and small toxic gas molecules ( H2S), were built for two different adsorption sites on graphene like aluminium nitride P(AlN)21. this was done by employing B3LYP density functional theory (DFT) with 6-31G*(d,p) using Gaussian 09 program, Gaussian viw5.0 package of programs and Nanotube Modeller program 2018. the adsorptions of H2S on P(AlN)21, (C) atoms-doped P(AL-N)20 sheet, D-P(AL-N)20 and D-(C)atoms-doped P(AL-N)19 (on atom) with (Ead) (-0.468eV),(-0.473 eV), (-0.457 eV), (-0.4478 eV) and (-0.454 eV), respectively, (Ead) of H2S on the center ring of the P(AL-N)21, (C) atoms-doped P(AL-N)20 sheet, D-P(AL-N)20 and D-(C,B)atoms-doped P(AL-N)19 sheet are (-0.280 eV),(-0.465 eV), (-0.405 eV), (-0.468 eV) and -0.282 eV), respectively, are weak physisorption . However, the adsorptions of H2S, on the ((AlN)20 -B and D- (AlN)19 -B), (on atom N and center ring the sheet) are a strong chemisorption because of the (Ead) larger than -0.5 eV, due to the strong interaction, the ((AlN)20-B and D-(AlN)19-B), could catalyst or activate, through the results that we obtained, which are the improvement of the sheet P(AlN)21 by doping and per forming a defect in, it that can be used to design sensors. DOI: http://dx.doi.org/10.31257/2018/JKP/2020/120210


2020 ◽  
Vol 860 ◽  
pp. 154-159
Author(s):  
Muhammad Redo Ramadhan ◽  
Irwan Ramli ◽  
Dita Puspita Sari ◽  
Budhy Kurniawan ◽  
Azwar Manaf ◽  
...  

Here we report spin-alignment contributions to muon coordinate calculated utilizing density functional theory (DFT) calculation. We estimated four different antiferromagnetic (AF) spin alignments in La2CuO4. We observed small changes by adjusting spin configurations in DFT calculations. Cu-spin value of 0.61 µB is constant in all calculations. The insulating gap of 1.9 eV is unchanged in all configurations. Muon coordinate was defined as the most minimum energy in atomic potential distribution. By assuming that Cu-spin is a point dipole for each atom, internal fields for muon were calculated and compared to known experimental results.


2020 ◽  
Vol 24 (05n07) ◽  
pp. 737-749
Author(s):  
Michael Haas ◽  
Sabrina Gonglach ◽  
Wolfgang Schöfberger

We report routes towards synthesis of novel [Formula: see text]-conjugated freebase cobalt, copper, gallium and manganese meso-alkynylcorroles. UV-vis spectra show that extensive peak broadening, red shifts, and changes in the oscillator strength of absorptions increase with the extension of [Formula: see text]-conjugation. Using density functional theory (DFT), we have carried out a first theoretical study of the electronic structure of these metallocorroles. Decreased energy gaps of about 0.3–0.4 eV between the HOMO and LUMO orbitals compared to the corresponding copper, gallium and manganese meso-5,10,15 triphenylcorrole are observed. In all cases, the HOMO energies are nearly unperturbed as the [Formula: see text]-conjugation is expanded. The contraction of the HOMO–LUMO energy gaps is attributed to the lowered LUMO energies.


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