scholarly journals CO oxidation catalysed by Pd-based bimetallic nanoalloys

2015 ◽  
Vol 17 (42) ◽  
pp. 28010-28021 ◽  
Author(s):  
Dennis Palagin ◽  
Jonathan P. K. Doye

Density functional theory based global geometry optimization has been used to demonstrate the crucial influence of the geometry of the catalytic cluster on the energy barriers for the CO oxidation reaction over Pd-based bimetallic nanoalloys.

RSC Advances ◽  
2016 ◽  
Vol 6 (61) ◽  
pp. 55867-55877 ◽  
Author(s):  
Wenping Zeng ◽  
Jian Tang ◽  
Pu Wang ◽  
Yong Pei

Using the icosahedra M13 (M = Au, Ag, Cu, Pt, Pd) and heteroatom doped Au18M clusters as model systems, the role of the co-adsorbed CO molecule played in the CO oxidation reaction is explored on the basis of density functional theory (DFT) calculations.


RSC Advances ◽  
2016 ◽  
Vol 6 (21) ◽  
pp. 17172-17178 ◽  
Author(s):  
Mehdi D. Esrafili ◽  
Parisa Nematollahi ◽  
Roghaye Nurazar

In this work, we employ density functional theory calculations to investigate the CO oxidation mechanisms over B12N12 and B11N12C nanocages.


Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1947
Author(s):  
Delano P. Chong

After geometry optimization, the electron spectra of indole and four azaindoles are calculated by density functional theory. Available experimental photoemission and excitation data for indole and 7-azaindole are used to compare with the theoretical values. The results for the other azaindoles are presented as predictions to help the interpretation of experimental spectra when they become available.


2013 ◽  
Vol 91 (9) ◽  
pp. 872-878 ◽  
Author(s):  
Stanislav R. Stoyanov ◽  
Cindy-Xing Yin ◽  
Murray R. Gray ◽  
Jeffrey M. Stryker ◽  
Sergey Gusarov ◽  
...  

The vanadium and nickel components in heavy oils and bitumen are important impurities in catalytic processing and form aggregates with other asphaltene components. Metalloporphyrins are commonly analyzed using the characteristic Soret band in the UV–vis absorption spectrum. However, the Soret band of metalloporphyrins in petroleum is broadened and weaker than expected based on the concentration of Ni and V in heavy oils and the extinction coefficients of isolated porphyrins. We hypothesize that the low intensity and broadening of the Soret band could be due to axial coordination of the metal center or fusion (annelation) of aromatic rings on the porphyrin π-system. This hypothesis is examined using the density functional theory for geometry optimization and time-dependent density functional theory (TD-DFT) for calculation of excited states of nickel(II) and vanadyl porphyrins with axially coordinated ligands and annelated polyaromatic hydrocarbons. Predictions of the excited electronic states performed using the tandem of TD-DFT and conductor-like polarizable continuum model of solvation support this hypothesis and provide insight into the extent of Soret band broadening and intensity decrease due to coordination and annelation. These computational results, validated with respect to visible absorption spectra, are important for understanding asphaltene aggregation and spectroscopic characterization and suggest methods for removal of transition metals from heavy oil.


2019 ◽  
Vol 21 (46) ◽  
pp. 25743-25748
Author(s):  
Yong-Chao Rao ◽  
Xiang-Mei Duan

The catalytic performance of Pd/Pt embedded planar carbon nitride for CO oxidation has been investigated via spin-polarized density functional theory calculations.


2017 ◽  
Vol 19 (33) ◽  
pp. 22344-22354 ◽  
Author(s):  
Sajjad Ali ◽  
Tian Fu Liu ◽  
Zan Lian ◽  
Bo Li ◽  
Dang Sheng Su

The mechanism of CO oxidation by O2 on a single Au atom supported on pristine, mono atom vacancy (m), di atom vacancy (di) and the Stone Wales defect (SW) on single walled carbon nanotube (SWCNT) surface is systematically investigated theoretically using density functional theory.


2013 ◽  
Vol 12 (05) ◽  
pp. 1350035 ◽  
Author(s):  
LIXIA YANG ◽  
XIAOLI LEI ◽  
JUN FENG ◽  
YUXIN ZHANG ◽  
MINGXING LIU

Comparative study about the adsorption and dissociation behaviors of H2O molecule on clean and vacancy defective Al (111) surface was conducted by extensive density functional theory (DFT) calculations, the interaction mechanisms between H2O molecule and Al (111) surface were also figured out. Geometry optimization results indicated that H2O molecule was apt to be adsorbed at top site on these two kinds of surfaces, whereas, the adsorption configurations, the adsorption type and inclination of H2O molecule planes away from the normal were different. The calculated adsorption energies demonstrated that the adsorption of H2O molecule occurred more readily on vacancy defective Al (111) surface. The electron density distribution indicated that the vacancy defect enhanced the interactions between H2O molecule and surface Al atoms. Further analysis of the density of states (DOS) showed that the vacancy defect increased the number of bonding electrons between H2O molecule and surface Al atoms. The detailed exploration of dissociation pathways demonstrated that the dissociation of H2O molecule on these two kinds of surfaces was a two-step process: (1) H2O → H + OH , (2) OH → H + O . However, for each step the dissociation pathway variations on vacancy defective Al (111) surface were different with those on clean Al (111) surface. Compared with the first step, the dissociation of hydroxyl group into O atom and H atom was kinetically difficult. The calculated lower activation energy barriers on vacancy defective Al (111) surface showed that the vacancy defect had catalytic effect for the dissociation of H2O molecule to some extent, especially for the first step.


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