Understanding surface site structures and properties by first principles calculations: an experimental point of view!

2017 ◽  
Vol 53 (31) ◽  
pp. 4296-4303 ◽  
Author(s):  
Aleix Comas-Vives ◽  
Kim Larmier ◽  
Christophe Copéret
Keyword(s):  
Heterogeneous Catalysis ◽  
First Principles ◽  
Active Sites ◽  
Rational Design ◽  
Molecular Level ◽  
Point Of View ◽  
Experimental Point ◽  
Surface Site ◽  
First Principles Calculations ◽  
Structures And Properties

Computational Chemistry is key for the molecular-level understanding of active sites in heterogeneous catalysis paving the way to the rational design and development.

scholarly journals Highly dispersed Pt atoms and clusters on hydroxylated indium tin oxide: A view from first-principles calculations

2021 ◽  
Author(s):  
Simran Kumari ◽  
Philippe Sautet
Keyword(s):  
Heterogeneous Catalysis ◽  
Metal Atom ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
First Principles ◽  
Catalytic Performance ◽  
Small Cluster ◽  
Single Atom ◽  
First Principles Calculations ◽  
Highly Dispersed

Supported single-atom and small cluster catalysts have become highly popular in heterogeneous catalysis. These catalysts can maximize the metal atom utilization while still showcasing superior catalytic performance. One of the...

The Influence of Surface Reconstruction and C-impurities on Photocatalytic Water Dissociation by TiO2

2003 ◽  
Vol 801 ◽  
Author(s):  
Xiliang Nie ◽  
Karl Sohlberg
Keyword(s):  
Surface Energy ◽  
Band Gap ◽  
First Principles ◽  
Active Sites ◽  
Water Dissociation ◽  
First Principles Calculations ◽  
Surface Band ◽  
Carbon Doped ◽  
Carbon Impurities ◽  
Photoabsorption Spectrum

ABSTRACTTiO2 is well known as a prototype photocatalyst for water dissociation. To understand the mechanism of its photocatalytic water dissociation we performed first-principles calculations. We find that the surface of the catalytically favorable (TiO) termination is very different from the physically favorable (oxygen) termination. The calculated surface energy of the catalytically favorable (TiO) termination is about 10 times larger than that of the physically favorable (oxygen) termination. Analysis of the surface band structure suggests that while O-vacancies are intrinsic active sites for water dissociation into H2 and O2 gas, they are not essential for photocatalytic water dissociation. We also find that carbon impurities decrease the band-gap of TiO2, in agreement with previously reported experimental results. Moreover, we identify the origin of the arcane “double band gap” in carbon doped TiO2. The two onsets seen in the photoabsorption spectrum result from excitations from two of three C p-states within the band gap, not from domains of different composition.

Oxide Thermoelectrics

2007 ◽  
Vol 1044 ◽  
Author(s):  
David Joseph Singh
Keyword(s):  
First Principles ◽  
Transport Theory ◽  
Point Of View ◽  
First Principles Calculations ◽  
Boltzmann Transport ◽  
Oxide Thermoelectrics ◽  
Seebeck Coefficients ◽  
Boltzmann Transport Theory ◽  
Strong Hybridization ◽  
Narrow Bands

AbstractThermoelectricity in oxides, especially NaxCoO2 and related materials, is discussed from the point of view of first principles calculations and Boltzmann transport theory. The electronic structure of this material is exceptional in that it has a combination of very narrow bands and strong hybridization between metal d states and ligand p states. As shown within the framework of conventional Boltzmann transport theory, this leads to high Seebeck coefficients even at metallic carrier densities. This suggests a strategy of searching for other narrow band oxides that can be doped metallic with mobile carriers. Some possible avenues for finding such materials are suggested.

scholarly journals Structural Evolution, Redox Mechanism, and Ionic Diffusion in Rhombohedral Na2FeFe(CN)6 for Sodium-Ion Batteries: First-Principles Calculations

2022 ◽  
Author(s):  
Ya-Ping Wang ◽  
B. P. Hou ◽  
Xin-Rui Cao ◽  
Shunqing Wu ◽  
Zi-Zhong Zhu
Keyword(s):  
First Principles ◽  
Rational Design ◽  
Low Cost ◽  
Magnetic Moments ◽  
Three Dimensional ◽  
Structural Evolution ◽  
Sodium Ion ◽  
High Rate ◽  
Sodium Ion Batteries ◽  
First Principles Calculations

Abstract Prussian blue analogs (Na2FeFe(CN)6) have been regarded as potential cathode materials for sodium-ion batteries (SIBs) due to their low-cost iron resources and open framework. Herein, the detailed first-principles calculations have been performed to investigate the electrochemical properties of NaxFeFe(CN)6 during Na ion extraction. The material undergoes a phase transition from a dense rhombohedral to open cubic structure upon half-desodiation, which is resulted from competition of the Na−N Coulomb attraction and d−π covalent bonding of Fe−N. The analyses on the density of states, magnetic moments and Bader charges of NaxFeFe(CN)6 reveal that there involve in the successive redox reactions of high-spin Fe2+/Fe3+ and low-spin Fe2+/Fe3+ couples during desodiation. Moreover, the facile three-dimensional diffusion channels for Na+ ions exhibit low diffusion barriers of 0.4 eV ~ 0.44 eV, which ensures a rapid Na+ transport in the NaxFeFe(CN)6 framework, contributing to high rate performance of the battery. This study gives a deeper understanding of the electrochemical mechanisms of NaxFeFe(CN)6 during Na+ extraction, which is beneficial for the rational design of superior PBA cathodes for SIBs.

Rational design of bifunctional ORR/OER catalysts based on Pt/Pd-doped Nb2CT2 MXene by first-principles calculations

2020 ◽  
Vol 8 (6) ◽  
pp. 3097-3108 ◽  
Author(s):  
Dongxiao Kan ◽  
Dashuai Wang ◽  
Xilin Zhang ◽  
Ruqian Lian ◽  
Jing Xu ◽  
...  
Keyword(s):  
First Principles ◽  
Rational Design ◽  
Bifunctional Catalyst ◽  
First Principles Calculations

Nb2CF2–VF–Pt is confirmed to be the best bifunctional catalyst toward ORR and OER, with relative low theoretical overpotentials (0.40 V for ORR and 0.37 V for OER).

NiO nanoparticle surface energy studies using first principles calculations

2018 ◽  
Vol 42 (13) ◽  
pp. 10791-10797 ◽  
Author(s):  
Junxiang Xiang ◽  
Bin Xiang ◽  
Xudong Cui
Keyword(s):  
Surface Energy ◽  
First Principles ◽  
Active Sites ◽  
Practical Importance ◽  
Catalytic Efficiency ◽  
First Principles Calculations ◽  
Miller Index ◽  
Surface Energies ◽  
Nanoparticle Surface

Understanding the correlations between active sites and surface energies of Miller index surfaces is of practical importance to get insights into catalytic efficiency.

Stability of two-dimensional PN monolayer sheets and their electronic properties

2015 ◽  
Vol 17 (47) ◽  
pp. 32009-32015 ◽  
Author(s):  
ShuangYing Ma ◽  
Chaoyu He ◽  
L. Z. Sun ◽  
Haiping Lin ◽  
Youyong Li ◽  
...  
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Structures And Properties

Three two-dimensional phosphorus nitride (PN) monolayer sheets (named as α-, β-, and γ-PN, respectively) with fantastic structures and properties are predicted based on first-principles calculations.

scholarly journals Nanoparticle shapes by using Wulff constructions and first-principles calculations

2015 ◽  
Vol 6 ◽  
pp. 361-368 ◽  
Author(s):  
Georgios D Barmparis ◽  
Zbigniew Lodziana ◽  
Nuria Lopez ◽  
Ioannis N Remediakis
Keyword(s):  
First Principles ◽  
Active Sites ◽  
Equilibrium Shape ◽  
Mathematical Formulation ◽  
Colloidal Suspensions ◽  
Advanced Materials ◽  
First Principles Calculations ◽  
Wulff Construction ◽  
Simple Method ◽  
Shape Of Nanoparticles

Background: The majority of complex and advanced materials contain nanoparticles. The properties of these materials depend crucially on the size and shape of these nanoparticles. Wulff construction offers a simple method of predicting the equilibrium shape of nanoparticles given the surface energies of the material. Results: We review the mathematical formulation and the main applications of Wulff construction during the last two decades. We then focus to three recent extensions: active sites of metal nanoparticles for heterogeneous catalysis, ligand-protected nanoparticles generated as colloidal suspensions and nanoparticles of complex metal hydrides for hydrogen storage. Conclusion: Wulff construction, in particular when linked to first-principles calculations, is a powerful tool for the analysis and prediction of the shapes of nanoparticles and tailor the properties of shape-inducing species.

scholarly journals The role of Sb in solar cell material Cu2ZnSnS4

2017 ◽  
Vol 5 (14) ◽  
pp. 6606-6612 ◽  
Author(s):  
Xiaoli Zhang ◽  
Miaomiao Han ◽  
Zhi Zeng ◽  
Yuhua Duan
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
First Principles ◽  
Point Of View ◽  
Efficiency Improvement ◽  
First Principles Calculations ◽  
Cell Material ◽  
Related Defect ◽  
Solar Cell Material

In this study, based on first-principles calculations we report a possible mechanism of efficiency improvement of Sb-doped Cu2ZnSnS4 (CZTS) solar cells from the Sb-related defect point of view.

scholarly journals Classifying Charge Carrier Interaction in Highly Compressed Elements and Silane

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4322
Author(s):  
Evgueni Talantsev
Keyword(s):  
Charge Carrier ◽  
First Principles ◽  
Point Of View ◽  
Recent Analysis ◽  
Theoretical Point ◽  
First Principles Calculations ◽  
Temperature Dependent ◽  
Primary Mechanism ◽  
Carrier Interaction ◽  
Black Phosphorous

Since the pivotal experimental discovery of near-room-temperature superconductivity (NRTS) in highly compressed sulphur hydride by Drozdov et al. (Nature 2015, 525, 73–76), more than a dozen binary and ternary hydrogen-rich phases exhibiting superconducting transitions above 100 K have been discovered to date. There is a widely accepted theoretical point of view that the primary mechanism governing the emergence of superconductivity in hydrogen-rich phases is the electron–phonon pairing. However, the recent analysis of experimental temperature-dependent resistance, R(T), in H3S, LaHx, PrH9 and BaH12 (Talantsev, Supercond. Sci. Technol. 2021, 34, accepted) showed that these compounds exhibit the dominance of non-electron–phonon charge carrier interactions and, thus, it is unlikely that the electron–phonon pairing is the primary mechanism for the emergence of superconductivity in these materials. Here, we use the same approach to reveal the charge carrier interaction in highly compressed lithium, black phosphorous, sulfur, and silane. We found that all these superconductors exhibit the dominance of non-electron–phonon charge carrier interaction. This explains the failure to demonstrate the high-Tc values that are predicted for these materials by first-principles calculations which utilize the electron–phonon pairing as the mechanism for the emergence of their superconductivity. Our result implies that alternative pairing mechanisms (primarily the electron–electron retraction) should be tested within the first-principles calculations approach as possible mechanisms for the emergence of superconductivity in highly compressed lithium, black phosphorous, sulfur, and silane.

Sign in / Sign up

Export Citation Format

Share Document