scholarly journals Molecularly soldered covalent organic frameworks for ultrafast precision sieving

2021 ◽  
Vol 7 (13) ◽  
pp. eabe8706 ◽  
Author(s):  
Yanqiu Zhang ◽  
Jing Guo ◽  
Gang Han ◽  
Yongping Bai ◽  
Qingchun Ge ◽  
...  
Keyword(s):  
Density Functional ◽  
State Of The Art ◽  
Condensation Polymerization ◽  
Functional Theory ◽  
Ion Removal ◽  
Molecular Separation ◽  
Stability Issues ◽  
Molecular Sieving ◽  
Counter Diffusion

The weak interlamellar interaction of covalent organic framework (COF) nanocrystals inhibit the construction of highly efficient ion/molecular sieving membranes owing to the inferior contaminant selectivity induced by defects in stacked COF membranes and stability issues. Here, a facile in situ molecularly soldered strategy was developed to fabricate defect-free ultrathin COF membranes with precise sieving abilities using the typical chemical environment for COF condensation polymerization and dopamine self-polymerization. The experimental data and density functional theory simulations proved that the reactive oxygen species generated during dopamine polymerization catalyze the nucleophilic reactions of the COF, thus facilitating the counter-diffusion growth of thin COF layers. Notably, dopamine can eliminate the defects in the stacked COF by soldering the COF crystals, fortifying the mechanical properties of the ultrathin COF membranes. The COF membranes exhibited ultrafast precision sieving for molecular separation and ion removal in both aqueous and organic solvents, which surpasses that of state-of-the-art membranes.

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh
Keyword(s):  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Transparent Electrode ◽  
Visible Range ◽  
Two Dimensional ◽  
Transparent Conductor ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

scholarly journals Measuring the structure and equation of state of polyethylene terephthalate at megabar pressures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. Lütgert ◽  
J. Vorberger ◽  
N. J. Hartley ◽  
K. Voigt ◽  
M. Rödel ◽  
...  
Keyword(s):  
Equation Of State ◽  
Polyethylene Terephthalate ◽  
Density Functional ◽  
Equations Of State ◽  
Md Simulations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Shock Hugoniot ◽  
Highly Correlated

AbstractWe present structure and equation of state (EOS) measurements of biaxially orientated polyethylene terephthalate (PET, $$({\hbox {C}}_{10} {\hbox {H}}_8 {\hbox {O}}_4)_n$$ ( C 10 H 8 O 4 ) n , also called mylar) shock-compressed to ($$155 \pm 20$$ 155 ± 20 ) GPa and ($$6000 \pm 1000$$ 6000 ± 1000 ) K using in situ X-ray diffraction, Doppler velocimetry, and optical pyrometry. Comparing to density functional theory molecular dynamics (DFT-MD) simulations, we find a highly correlated liquid at conditions differing from predictions by some equations of state tables, which underlines the influence of complex chemical interactions in this regime. EOS calculations from ab initio DFT-MD simulations and shock Hugoniot measurements of density, pressure and temperature confirm the discrepancy to these tables and present an experimentally benchmarked correction to the description of PET as an exemplary material to represent the mixture of light elements at planetary interior conditions.

In Situ Exsolved Au Nanoparticles from Perovskite Oxide for Efficient Epoxidation of Styrene

2021 ◽  
Author(s):  
Yang Gao ◽  
Xing Chen ◽  
Shuqi Hu ◽  
Shiguo Zhang
Keyword(s):  
Density Functional Theory ◽  
Thermodynamic Analysis ◽  
Density Functional ◽  
Au Nanoparticles ◽  
Oxide Catalyst ◽  
Density Functional Theory Calculations ◽  
Average Diameter ◽  
Perovskite Oxide ◽  
Functional Theory

Au-doped SrTiO3 perovskite oxide catalyst (Sr0.995Au0.005TiO3-δ) has been designed and synthesized based on thermodynamic analysis and density functional theory calculations. During reduction, Au nanoparticles with an average diameter of 2...

scholarly journals Ultra-narrow blue phosphorene nanoribbons for tunable optoelectronics

RSC Advances ◽  
2017 ◽  
Vol 7 (5) ◽  
pp. 2992-3002 ◽  
Author(s):  
Ram Swaroop ◽  
P. K. Ahluwalia ◽  
K. Tankeshwar ◽  
Ashok Kumar
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
State Of The Art ◽  
The State ◽  
Optoelectronic Properties ◽  
Functional Theory ◽  
Theory Framework ◽  
Blue Phosphorene

We report optoelectronic properties of ultra-narrow blue phosphorene nanoribbons (BPNRs) within the state-of-the-art density functional theory framework.

The catalytic mechanism of the Au@TiO2−x/ZnO catalyst towards a low-temperature water-gas shift reaction

2020 ◽  
Vol 10 (3) ◽  
pp. 768-775
Author(s):  
Ning Liu ◽  
Pan Yin ◽  
Ming Xu ◽  
Yusen Yang ◽  
Shaomin Zhang ◽  
...  
Keyword(s):  
Density Functional ◽  
Catalytic Mechanism ◽  
Density Functional Theory Calculation ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Functional Theory ◽  
Shift Reaction ◽  
Water Gas ◽  
Theory Calculation

A redox mechanism towards the water-gas shift reaction was certified based on in situ/operando experiments and density functional theory calculation studies.

A combined study of the equation of state of monazite-type lanthanum orthovanadate usingin situhigh-pressure diffraction andab initiocalculations

2014 ◽  
Vol 70 (3) ◽  
pp. 533-538 ◽  
Author(s):  
Olga Ermakova ◽  
Javier López-Solano ◽  
Roman Minikayev ◽  
Stefan Carlson ◽  
Agata Kamińska ◽  
...  
Keyword(s):  
Equation Of State ◽  
Density Functional ◽  
Room Temperature ◽  
Theoretical Data ◽  
Perfect Agreement ◽  
Functional Theory ◽  
Compression Direction ◽  
The Density Functional Theory ◽  
Murnaghan Equation

Lanthanum orthovanadate (LaVO4) is the only stable monazite-type rare-earth orthovanadate. In the present paper the equation of state of LaVO4is studied usingin situhigh-pressure powder diffraction at room temperature, andab initiocalculations within the framework of the density functional theory. The parameters of a second-order Birch–Murnaghan equation of state,i.e.those fitted to the experimental and theoretical data, are found to be in perfect agreement – in particular, the bulk moduli are almost identical, with values of 106 (1) and 105.8 (5) GPa, respectively. In agreement with recent reported experimental data, the compression is shown to be anisotropic. Its nature is comparable to that of some other monazite-type compounds. The softest compression direction is determined.

scholarly journals Intercalation of Mn in graphene/Cu(111) interface: insights to the electronic and magnetic properties from theory

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Qilin Guo ◽  
Yuriy Dedkov ◽  
Elena Voloshina
Keyword(s):  
Fermi Level ◽  
Density Functional ◽  
Dirac Point ◽  
State Of The Art ◽  
Structural Models ◽  
Electronic States ◽  
Density Functional Theory Calculations ◽  
Linear Dispersion ◽  
Functional Theory ◽  
Favorable Configuration

AbstractThe effect of Mn intercalation on the atomic, electronic and magnetic structure of the graphene/Cu(111) interface is studied using state-of-the-art density functional theory calculations. Different structural models of the graphene–Mn–Cu(111) interface are investigated. While a Mn monolayer placed between graphene and Cu(111) (an unfavorable configuration) yields massive rearrangement of the graphene-derived $$\pi $$ π bands in the vicinity of the Fermi level, the possible formation of a $$\hbox {Cu}_2$$ Cu 2 Mn alloy at the interface (a favorable configuration) preserves the linear dispersion for these bands. The deep analysis of the electronic states around the Dirac point for the graphene/$$\hbox {Cu}_2$$ Cu 2 Mn/Cu(111) system allows to discriminate between contributions from three carbon sublattices of a graphene layer in this system and to explain the bands’ as well as spins’ topology of the electronic states around the Fermi level.

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