Article
Chemistry, Multidisciplinary
Vasileios Fotopoulos, David Mora-Fonz, Manuel Kleinbichler, Rishi Bodlos, Ernst Kozeschnik, Lorenz Romaner, Alexander L. Shluger
Summary: In this study, computational modeling was used to investigate the structures, formation energies, and migration mechanisms of vacancy clusters in fcc metals. The results showed that di-vacancies have a smaller migration barrier compared to mono-vacancies and other clusters, and this barrier is further reduced at grain boundaries. These findings are important for understanding the structural evolution and diffusion mechanisms of metal films under thermal and mechanical stress.
Article
Chemistry, Physical
Aaron D. Kaplan, Stewart J. Clark, Kieron Burke, John P. Perdew
Summary: Classical turning surfaces of Kohn-Sham potentials separate classically allowed regions (CARs) from classically forbidden regions (CFRs). The presence and distribution of CFRs vary in different materials based on factors such as material type and internuclear distances. Many semiconductors have no CFR at equilibrium, which is crucial for density functional construction.
NPJ COMPUTATIONAL MATERIALS
(2021)
Article
Chemistry, Physical
Calvin Ku, Patrick H. -L. Sit
Summary: By using oxidation-state constrained density functional theory (OS-CDFT), researchers studied the polaron dynamics in MoS2 and found similar characteristics in both monolayer and bulk materials. The presence of S and Mo vacancies near the polarons affected the driving force, which ultimately impacts electron mobility in MoS2.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Soufiane Bahou, Hicham Labrim, Hamid Ez-Zahraouy
Summary: By using the Korringa-Kohn-Rostoker method, the researchers investigate the effects of doping with transition metals and creating magnesium vacancies on the thermodynamic properties of MgH2. The results show that the heat of formation increases with higher concentrations of magnesium vacancies and transition metals, while the decomposition temperature and stability decrease. The weak hybridization between the doped elements and hydrogen atoms, as well as the faster movement of hydrogen atoms in the structure, contribute to the improvement of the thermodynamic properties. The optimal concentrations for practical use are determined to be 6.1% for Mg1-x-yMnxH2, 6.4% for Mg1-x-yCrxH2, and 7.1% for Mg1-x-yVxH2.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Biochemistry & Molecular Biology
Xiaoji Zhao, Yanlu Li, Xian Zhao
Summary: This study investigates the structure, stability, and electronic structure of hydrogen and oxygen vacancy defects on the (100) and (101) growth surfaces of KDP crystals using density functional theory. The effects of acidic and alkaline environments on surface defects are also discussed. The results show that different vacancy defects have varying properties on different surfaces, and acidic environments are conducive to repairing surface defects.
Article
Biochemistry & Molecular Biology
Maryam RaeisianAsl, Saeedeh Sarabadani Tafreshi, Nora H. H. de Leeuw
Summary: Density functional theory calculations were used to study the effects of replacing lead with alkaline earth metals on the stability, electronic, and optical properties of formamidinium lead triiodide (FAPbI(3)) (111) and (100) surfaces. The results show that the (111) surface is more stable and exhibits metallic characteristics. The (100) surfaces have suitable bandgaps and doping with magnesium or calcium increases the bandgap, while doping with beryllium decreases the bandgap. Optimal absorption and light harvesting efficiency were achieved for plain and doped (100) surfaces in the visible and near UV regions.
Article
Materials Science, Multidisciplinary
Jia-Li Chen, Nikolas Kaltsoyannis
Summary: Understanding actinide mixed oxides is crucial for the development of nuclear fuel and the storage of spent fuel. This study provides systematic simulations of AnO(2) and U-An MOX using density functional theory, focusing on spin density and density of states. Conclusions are drawn regarding oxidation states and transition regions between different systems.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Shujie Zhang, Kejiang Li, Yan Ma, Yushan Bu, Zeng Liang, Zonghao Yang, Jianliang Zhang
Summary: This study employs density functional theory (DFT) to investigate the adsorption behavior of hydrogen atoms and H-2 on different crystal FeO surfaces. It reveals that Fe (catalytic site) and O (binding site) atoms contribute to the interaction between H-2 and FeO surfaces.
Article
Chemistry, Physical
Jinru Sun, Aolei Song, Yu Tian, Hua Zhan, Jianlin Deng, Hong Wang, Ming Ke
Summary: In this study, the effect of alkali metal deposition on the activity of x-Co3O4 catalysts for the N2O catalytic decomposition was investigated. The results showed that the deposition of alkali metal Na improved the activity of the Na-Co3O4 catalyst, while the deposition of other alkali metals suppressed the catalytic decomposition of N2O. Characterization analysis indicated that the deposition of alkali metals did not change the morphology and structure of the catalysts but affected the chemical environment around the Co ion.
Article
Chemistry, Multidisciplinary
Gyuweon Jung, Suyeon Ju, Kangwook Choi, Jaehyeon Kim, Seongbin Hong, Jinwoo Park, Wonjun Shin, Yujeong Jeong, Seungwu Han, Woo Young Choi, Jong-Ho Lee
Summary: This study proposes a method to manipulate the amount of surface oxygen on metal oxide surfaces by electrically controlling the electron concentration of the metal oxide. The method is effective, repeatable, and does not require severe settings. It can selectively increase oxidizing and reducing gas reactions by reconfiguring the oxygen vacancies on the metal oxide surfaces. The proposed method is applied to gas sensors and overcomes their existing limitations, making the sensors insensitive to certain gases in mixed-gas environments and providing a rapid and linear response to target gas concentrations.
Article
Chemistry, Applied
Guangdong Liu, Huiqiu Deng, Jeffrey Greeley, Zhenhua Zeng
Summary: This study reveals that under anhydrous conditions, (111) terrace sites are inactive for the oxygen reduction reaction (ORR) while step edges, particularly the (110) type with a unique accumulation of O, exhibit lower overpotential and serve as the active sites for ORR.
CHINESE JOURNAL OF CATALYSIS
(2022)
Article
Chemistry, Physical
Sihang Liu, Nitish Govindarajan, Karen Chan
Summary: This study investigates the reaction mechanism of furfural hydrogenation to furfuryl alcohol using density functional theory calculations and microkinetic modeling. The results show that the binding energy of furfural is a good predictor of the activity trends for furfuryl alcohol production. Additionally, Cu-based alloys are found to be the most active catalysts for this reaction.
Article
Chemistry, Physical
Ronen Kruchinin, Oswaldo Dieguez
Summary: In this article, density-functional theory calculations are used to study the energetics of CO2 reduction to methane via the Sabatier reaction on sulfur-based transition-metal dichalcogenides (TMDs) with non-, Ni- and Cu-doping. It is found that sulfur-based TMDs with Ni/Cu doping exhibit better indicators for catalytic performance of the CO2 reduction reaction compared to non-doped and doped TMDs without active sites. Furthermore, the role of the chalcogen and dopant atoms in influencing bonding strength and type is found to have a much bigger influence on the reaction than the transition metal.
Article
Energy & Fuels
Kun Wang, Kunlun Li, Fuqing Wang
Summary: In this study, the adsorption of CO onto the surface of nickel was investigated using density functional theory (DFT). The adsorption parameters and electronic states of CO on different nickel surfaces with varying coverage levels were calculated. The results showed that the most stable adsorption sites were valley sites on Ni(111) and Ni(100) surfaces, and a short bridge site on the Ni(110) surface. The energy comparison indicated that CO adsorption on the Ni(100) surface was the most favorable. Additionally, the density of states analysis revealed that the adsorption mechanism involved orbital hybridization.
Article
Nanoscience & Nanotechnology
Biswarup Pathak, Mohan Tiwari, Shyama Charan Mandal, Amitabha Das
Summary: In this study, density functional theory (DFT) calculations were used to investigate the upgrading of ethanol to n-butanol. The Li-subsurface Cu(111) structure was found to be the most stable and was used for the mechanistic investigation. The improved activity can be attributed to the charge transfer from Li to the Cu surface, which enhances the adsorption of important intermediates through an oxygen atom. This study contributes to the rational design of high-performance metal catalysts and emphasizes the importance of subsurface chemistry in heterogeneous catalysis.
ACS APPLIED NANO MATERIALS
(2023)
