scholarly journals Efficient nickel-based catalysts for amine regeneration of CO2 capture: From experimental to calculations verifications

2021 ◽  
Author(s):  
Qiang Sun ◽  
Yu Mao ◽  
Hongxia Gao ◽  
Teerawat Sema ◽  
Sen Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Co2 Capture ◽  
Density Functional ◽  
Catalytic Mechanism ◽  
Theoretical Calculations ◽  
High Heat ◽  
Catalytic Performance ◽  
Industrial Applications ◽  
Co2 Desorption ◽  
The Density Functional Theory

High heat duty is an urgent challenge for industrial applications of amine-based CO2 capture. In this work, we report a novel, stable, efficient, and inexpensive Ni-HZSM-5 catalyst to reduce the heat duty. The density functional theory (DFT) calculations successfully explain the catalytic performance. The catalytic activity associates with the combined properties of MSA × B/L × Ni2+. The 7.85-Ni-HZ catalyst presents an excellent catalytic activity for the CO2 desorption: it increases the amount of desorbed CO2 up to 36%, reduces the heat duty by 27.07% compared with the blank run, and possesses high stability during five cyclic tests. A possible catalytic mechanism for the Ni-HZSM-5 catalysts through assisting carbamate breakdown and promoting CO2 desorption is proposed based on experimental results and theoretical calculations. Therefore, the results present that the 7.85-Ni-HZ catalyst significantly accelerates the protons transfer in CO2 desorption and can potentially apply in industrial CO2 capture.

scholarly journals On the Effects of Doping on the Catalytic Performance of (La,Sr)CoO3. A DFT Study of CO Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 312 ◽  
Author(s):  
Antonella Glisenti ◽  
Andrea Vittadini
Keyword(s):  
Catalytic Activity ◽  
Co Oxidation ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Formation Energy ◽  
Oxygen Vacancies ◽  
Catalytic Performance ◽  
Energy Profiles ◽  
High Concentrations ◽  
3D Impurities

The effects of modifying the composition of LaCoO3 on the catalytic activity are predicted by density functional calculations. Partially replacing La by Sr ions has benefical effects, causing a lowering of the formation energy of O vacancies. In contrast to that, doping at the Co site is less effective, as only 3d impurities heavier than Co are able to stabilize vacancies at high concentrations. The comparison of the energy profiles for CO oxidation of undoped and of Ni-, Cu-m and Zn-doped (La,Sr)CoO3(100) surface shows that Cu is most effective. However, the effects are less spectacular than in the SrTiO3 case, due to the different energetics for the formation of oxygen vacancies in the two hosts.

scholarly journals Bimetallic nanocatalysts PtCu and PtNi for fuel cells

2020 ◽  
Vol 21 (2) ◽  
pp. 211-214
Author(s):  
O. M. Chernikova ◽  
Y. V. Ogorodnik
Keyword(s):  
Density Functional ◽  
Bimetallic Catalyst ◽  
Theoretical Calculations ◽  
Catalyst Activity ◽  
Main Research ◽  
Heterogeneous Catalytic ◽  
Physical Mechanisms ◽  
Oxidation Of Methanol ◽  
The Density Functional Theory ◽  
Bimetallic Nanocatalysts

We review the physical mechanisms of heterogeneous catalytic oxidizing reactions methanol oxidation using bimetallic film layered mechanically strained PtNi and PtCu-based catalysts. The main research methods are theoretical calculations based on the density functional theory and the ˝ab initio˝ pseudopotential method. The work illustrates that the mechanical stress and the presence of dissociated oxygen have the greatest impact on increasing electron bimetallic catalyst activity during the oxidation of methanol with using bimetallic layered mechanically strained PtNi and PtCu-based catalysts. The compression of the platinum film pushes the electron density outside the film and it gives the density an elongated form and increases the chemical and absorption activity of the film.

scholarly journals Theoretical Calculations on the Mechanism of Enantioselective Copper(I)-Catalyzed Addition of Enynes to Ketones

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 359 ◽  
Author(s):  
Hanwei Li ◽  
Mingliang Luo ◽  
Guohong Tao ◽  
Song Qin
Keyword(s):  
Density Functional Theory ◽  
Steric Hindrance ◽  
Phenyl Ring ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Dft Method ◽  
Catalytic Cycle ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Chiral Systems

Computational investigations on the bisphospholanoethane (BPE)-ligated Cu-catalyzed enantioselective addition of enynes to ketones were performed with the density functional theory (DFT) method. Two BPE-mesitylcopper (CuMes) catalysts, BPE-CuMes and (S,S)-Ph-BPE–CuMes, were employed to probe the reaction mechanism with the emphasis on stereoselectivity. The calculations on the BPE-CuMes system indicate that the active metallized enyne intermediate acts as the catalyst for the catalytic cycle. The catalytic cycle involves two steps: (1) ketone addition to the alkene moiety of the metallized enyne; and (2) metallization of the enyne followed by the release of product with the recovery of the active metallized enyne intermediate. The first step accounts for the distribution of the products, and therefore is the stereo-controlling step in chiral systems. In the chiral (S,S)-Ph-BPE–CuMes system, the steric hindrance is vital for the distribution of products and responsible for the stereoselectivity of this reaction. The steric hindrance between the phenyl ring of the two substrates and groups at the chiral centers in the ligand skeleton is identified as the original of the stereoselectivity for the titled reaction.

Efficient hydrogenolysis of aryl ethers over Ce-MOF supported Pd NPs under mild conditions: mechanistic insight using density functional theoretical calculations

2020 ◽  
Vol 10 (20) ◽  
pp. 6892-6901
Author(s):  
Ashish Kumar Kar ◽  
Surinder Pal Kaur ◽  
T. J. Dhilip Kumar ◽  
Rajendra Srivastava
Keyword(s):  
Catalytic Activity ◽  
Adsorption Energy ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Desorption Energy ◽  
Mild Conditions ◽  
Mechanistic Insight ◽  
Aryl Ethers ◽  
Benzyl Phenyl Ether ◽  
Supported Pd

The significant Pd0 content and optimum bonding of the reactant & product (higher adsorption energy of benzyl phenyl ether and lower desorption energy for phenol) are responsible for the exceptional catalytic activity of Pd/Ce-MOF.

Enhanced Catalytic Activity of Carbon Nanotubes for the Oxidation of Cyclohexane by Filling with Fe, Ni, and FeNi alloy Nanowires

2016 ◽  
Vol 69 (6) ◽  
pp. 689 ◽  
Author(s):  
Xixian Yang ◽  
Yuhang Li ◽  
Hao Yu ◽  
Xuchun Gui ◽  
Hongjuan Wang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Catalytic Activity ◽  
Wall Thickness ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Catalytic Performance ◽  
General Strategy ◽  
Thin Walls ◽  
Alloy Nanowires ◽  
Relationship Of

Fe-, Ni-, and alloyed FeNi-filled carbon nanotubes (Fe@CNT, Ni@CNT, and FeNi@CNT) were prepared by a general strategy using a mixture of xylene and dichlorobenzene as carbon source, and ferrocene, nickelocene, and their mixture as catalysts. By tailoring the composition of the carbon precursor, the filling ratio and the wall thickness of metal@CNT could be controlled. For the catalytic oxidation of cyclohexane in liquid phase with molecular oxygen as oxidant, the highest activity was obtained over Fe@CNT synthesized from pure dichlorobenzene. However, Ni filling did not improve the activity of CNTs. The effects of metal filling, wall thickness, and defects on catalytic activity were investigated to determine the structure–activity relationship of the filled CNTs. The enhanced catalytic performance can be attributed to a combined contribution of thin walls of CNTs and confined electron-donating metals, which are favourable to electron transfer on the surfaces of CNTs. The modification of the electronic structure of CNTs upon Fe and Ni fillers insertion was elucidated through density functional theory calculations.

First principle investigations of the optical properties of Zn1-xMgxS, Zn1-xMgxSe and Zn1-xMgxTe ternary alloys

2014 ◽  
Vol 28 (31) ◽  
pp. 1450221 ◽  
Author(s):  
M. Dadsetani ◽  
A. Zeinivand
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Random Phase ◽  
Ternary Alloys ◽  
Optical Absorption Coefficient ◽  
Full Potential ◽  
Generalized Gradient ◽  
The Density Functional Theory ◽  
Ternary Semiconductor

Optical properties of Zn 1-x Mg x S , Zn 1-x Mg x Se and Zn 1-x Mg x Te (0 ≤ x ≤ 1) ternary semiconductor alloys are calculated using the full potential linearized augmented plane wave within the density functional theory. The exchange correlation potential is treated by the generalized gradient approximation (GGA) within Perdew et al. scheme. The real and imaginary parts of the dielectric function ε(ω), the refractive index n(ω), the extinction coefficient k(ω), the optical absorption coefficient α(ω), the reflectivity R(ω) and the electron energy loss function (EELS) are calculated within random phase approximation (RPA). Our results are compared with the previous theoretical calculations and available experimental data. Moreover, the interband transitions responsible for the structures seen in the spectra are specified. It is shown that, the chalcogen p states as initial and Zn 4s, Mg 3s, chalcogen d states as final states perform the major role in optical transitions.

High-heat treatment enhanced catalytic activity of CuO/CeO2 catalysts with low CuO content for CO oxidation

2020 ◽  
Vol 10 (15) ◽  
pp. 5256-5266 ◽  
Author(s):  
Jihang Yu ◽  
Qiangsheng Guo ◽  
Xiuzhen Xiao ◽  
Haifang Mao ◽  
Dongsen Mao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Active Sites ◽  
High Heat ◽  
Catalytic Performance

CuO/CeO2 catalysts with low CuO content and calcined at 800 °C exhibited better catalytic performance than those calcined at 500 °C. The coordinatively unsaturated copper atoms were proved to be the main active sites in the CuO/CeO2 catalysts.

scholarly journals Optical Properties of DMA-π-DCV Derivatives: A Theoretical Inspection under the DFT Microscope

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Joaquín Calbo
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Test System ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Donor Acceptor ◽  
Derivatives Of ◽  
Bridge Length ◽  
Theory Framework

The optical properties of a series of donor-acceptor N,N-dimethylaniline-π-dicyanovinylene (DMA-π-DCV) chromophores have been investigated under the density functional theory framework. Focus has been made on the low-lying charge-transfer (CT) electronic transitions for which experimental data is available. The effect of theπ-conjugated bridge length and type was analysed between the families of oligoene and oligoyne derivatives of increasing size. Theoretical calculations demonstrate that the ethylene bridge is a betterπ-communicator and allows for more delocalized frontier molecular orbitals compared to the acetylene spacer. TheΛdiagnostic test allowed rationalization of the orbital spatial overlap in the main CT excitations. The performance of different density functional rungs was assessed in the prediction of the lowest-lying CT electronic transition. Surprisingly, most modern long-range corrected functionals demonstrated to provide among the largest errors, whereas hybrid functionals showed the best performance. Solvatochromism was confirmed in both oligoene and oligoyne compounds. A donor-acceptor-donor triad based on tetrathiafulvalene was utilised as a test system for the prediction of its two CT bands of different nature, energy, and intensity. The hybrid PBE0 (or a similar hybrid analogue) consolidates as the best choice for the prediction of CT excitations in the DMA-π-DCV push-pull family.

A theoretical investigation on promising acceptor groups for POM-based dyes: from electronic structure to photovoltaic conversion efficiency

2020 ◽  
Vol 8 (1) ◽  
pp. 219-227 ◽  
Author(s):  
Yu Gao ◽  
Wei Guan ◽  
Li-Kai Yan ◽  
Zhong-Min Su
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Time Dependent ◽  
Functional Theory ◽  
Photovoltaic Conversion Efficiency ◽  
Acceptor Group ◽  
The Density Functional Theory ◽  
Td Dft

Theoretical calculations based on the density functional theory (DFT) and time-dependent DFT (TD-DFT) were employed to screen efficient acceptor group candidates for POM-based dyes.

Modification of the catalytic properties of the Au4 nanocluster for the conversion of methane-to-methanol: synergistic effects of metallic adatoms and a defective graphene support

2015 ◽  
Vol 17 (15) ◽  
pp. 9706-9715 ◽  
Author(s):  
J. Sirijaraensre ◽  
J. Limtrakul
Keyword(s):  
Density Functional Theory ◽  
Catalytic Activity ◽  
Density Functional ◽  
Catalytic Properties ◽  
Synergistic Effects ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Oxidation Of Methane ◽  
The Density Functional Theory ◽  
Conversion Of Methane

By means of the density functional theory calculations, enhanced catalytic activity of Au4 cluster for the partial oxidation of methane with the N2O oxidant is observed when the cluster is deposited on top of the Pd/graphene.

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