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).

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.

Single-Molecule Piezoelectric Deformation: Rational Design from First-Principles Calculations

2013 ◽  
Vol 117 (33) ◽  
pp. 16783-16790 ◽  
Author(s):  
Xinfeng Quan ◽  
Christopher W. Marvin ◽  
Leah Seebald ◽  
Geoffrey R. Hutchison
Keyword(s):  
Single Molecule ◽  
First Principles ◽  
Rational Design ◽  
First Principles Calculations

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 Unraveling energy and charge transfer in type-II van der Waals heterostructures

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Junyi Liu ◽  
Zi Li ◽  
Xu Zhang ◽  
Gang Lu
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
First Principles ◽  
Rational Design ◽  
Van Der Waals ◽  
Band Alignment ◽  
Type Ii ◽  
First Principles Calculations ◽  
Comprehensive Picture ◽  
Excitonic Effect

AbstractRecent experiments observed significant energy transfer in type-II van der Waals (vdW) heterostructures, such as WS2/MoSe2, which is surprising due to their staggered band alignment and weak spectral overlap. In this work, we carry out first-principles calculations to shed light on energy and charge transfer in WS2/MoSe2 heterostructure. Incorporating excitonic effect in nonadiabatic electronic dynamics, our first-principles calculations uncover a two-step process in competing energy and charge transfer, unravel their relative efficiencies and explore the means to control their competition. While both Dexter and Förster mechanisms can be responsible for energy transfer, they are shown to operate at different conditions. The excitonic effect is revealed to drive ultrafast energy and charge transfer in type-II WS2/MoSe2 heterostructure. Our work provides a comprehensive picture of exciton dynamics in vdW heterostructures and paves the way for rational design of novel vdW heterostructures for optoelectronic and photovoltaic applications.

Electronic Structure and X-ray Absorption Spectra of Rutile TiO2 Using First-Principles Calculations

2014 ◽  
Vol 52 (12) ◽  
pp. 1025-1029
Author(s):  
Min-Wook Oh ◽  
Tae-Gu Kang ◽  
Byungki Ryu ◽  
Ji Eun Lee ◽  
Sung-Jae Joo ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Absorption Spectra ◽  
First Principles ◽  
First Principles Calculations ◽  
Rutile Tio2 ◽  
X Ray ◽  
X Ray Absorption

To Bend or Not to Bend, the Dilemma of Multiple Bonds

2019 ◽  
Author(s):  
Michele Pizzocchero ◽  
Matteo Bonfanti ◽  
Rocco Martinazzo
Keyword(s):  
First Principles ◽  
2D Materials ◽  
Main Group ◽  
First Principles Calculations ◽  
Group 14 ◽  
Multiple Bonds ◽  
Main Group Elements ◽  
Structural Distortions

The manuscript addresses the issue of the structural distortions occurring at multiple bonds between high main group elements, focusing on group 14. These distortions are known as trans-bending in silenes, disilenes and higher group analogues, and buckling in 2D materials likes silicene and germanene. A simple but correlated \sigma + \pi model is developed and validated with first-principles calculations, and used to explain the different behaviour of second- and higher- row elements.

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

2019 ◽  
Author(s):  
Henrik Pedersen ◽  
Björn Alling ◽  
Hans Högberg ◽  
Annop Ektarawong
Keyword(s):  
Thin Films ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Van Der Waals ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

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