A first-principles computational comparison of defect-free and disordered, fluorinated anatase TiO2 (001) interfaces with water

Chemical doping and other surface modifications have been used to engineer the bulk properties of materials, but their influence on the surface structure and consequently the surface chemistry are often unknown. Previous work has been successful in fluorinating anatase TiO2 with charge balance achieved via the introduction of Ti vacancies rather than the reduction of Ti. Our work here investigates the interface between this fluorinated titanate with cationic vacancies and a monolayer of water via density functional theory based molecular dynamics. We compute the projected density of states for only those atoms at the interface and for those states that fall within 1eV of the Fermi energy for various steps throughout the simulation, and we determine that the variation in this representation of the density of states serves as a reasonable tool to anticipate where surfaces are most likely to be reactive. In particular, we conclude that water dissociation at the surface is the main mechanism that influences the anatase (001) surface whereas the change in the density of states at the surface of the fluorinated structure is influenced primarily through the adsorption of water molecules at the surface.

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A First-Principles Computational Comparison of the Aqueous Anatase TiO2 (001) Interface and the Disordered, Fluorinated TiO2 Interface

10.26434/chemrxiv.7076816 ◽

2018 ◽

Author(s):

Kyle Reeves ◽

Damien Dambournet ◽

Christel Laberty-Robert ◽

Rodolphe Vuilleumier ◽

Mathieu Salanne

Keyword(s):

Density Of States ◽

Density Functional ◽

Water Dissociation ◽

Water Molecules ◽

Chemical Doping ◽

Charge Balance ◽

Functional Theory ◽

Adsorption Of Water ◽

Properties Of Materials ◽

Computational Comparison

Chemical doping and other surface modifications have been used to engineer the bulk properties of materials, but their influence on the surface structure and consequently the surface chemistry are often unknown. Previous work has been successful in fluorinating anatase TiO2 with charge balance achieved via the introduction of Ti vacancies rather than the reduction of Ti. Our work here investigates the interface between this fluorinated titanate with cationic vacancies and a monolayer of water via density functional theory based molecular dynamics. We compute the projected density of states for only those atoms at the interface and for those states that fall within 1eV of the Fermi energy for various steps throughout the simulation, and we determine that the variation in this representation of the density of states serves as a reasonable tool to anticipate where surfaces are most likely to be reactive. In particular, we conclude that water dissociation at the surface is the main mechanism that influences the anatase (001) surface whereas the change in the density of states at the surface of the fluorinated structure is influenced primarily through the adsorption of water molecules at the surface.

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SURFACE MODIFICATIONS OF ACTIVATED CARBON AND ITS IMPACT ON APPLICATION

Surface Review and Letters ◽

10.1142/s0218625x1830006x ◽

2019 ◽

Vol 26 (01) ◽

pp. 1830006 ◽

Cited By ~ 2

Author(s):

MATHEUS PEGO ◽

JANAÍNA CARVALHO ◽

DAVID GUEDES

Keyword(s):

Surface Modification ◽

Activated Carbon ◽

Surface Chemistry ◽

Surface Structure ◽

Adsorption Capacity ◽

Activated Carbons ◽

Surface Modifications ◽

Hazardous Substances ◽

Carbon Surface ◽

Corona Treatment

The main and new surface modification methods of activated carbon (AC) and their influence on application (adsorption capacity) were reviewed. Adsorption capacity is an important issue, contributing to hazardous substances environment management. According to literature, it is true that surface chemistry strongly affects adsorption capacity. Surface chemistry can be modified by several methods that lead to different activated carbon properties. Furthermore, adsorbate properties, and their relationships with surface structure, can impact adsorption properties. Surface modifications can be conducted by adding some atoms to the surface structure, making the surface more acidic or basic. Introduction of oxygen and ammonia atoms (chemical modification) are the main processes to make the surface more acidic and basic, respectively, although may bring chemical wastes to environment. Surface modification is done by chemical and physical modifications that lead activated carbons to present different properties. The main and new methods of chemical and physical modifications are compared and presented in this paper. Some new physical methods, like corona treatment, plasma discharge and microwave radiation, can be applied to cause surface modifications. Corona treatment can be a practical and new way to cause surface modification on an activated carbon surface.

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Combined first-principles and electromagnetic simulation study of n -type doped anatase TiO2 for the applications in infrared surface plasmon photonics

Physical Review Materials ◽

10.1103/physrevmaterials.4.055201 ◽

2020 ◽

Vol 4 (5) ◽

Author(s):

Thien Duc Ngo ◽

Thang Duy Dao ◽

Nguyen Thanh Cuong ◽

Naoto Umezawa ◽

Tadaaki Nagao

Keyword(s):

Surface Plasmon ◽

Simulation Study ◽

First Principles ◽

Anatase Tio2 ◽

Electromagnetic Simulation

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First-principles study of the morphology and surface structure of LaCoO3 and La0.5Sr0.5Fe0.5Co0.5O3 perovskites as air electrodes for solid oxide fuel cells

Science and Technology of Advanced Materials: Methods ◽

10.1080/27660400.2021.1909871 ◽

2021 ◽

Vol 1 (1) ◽

pp. 24-33

Author(s):

Masanobu Nakayama ◽

Katsuya Nishii ◽

Kentaro Watanabe ◽

Naoto Tanibata ◽

Hayami Takeda ◽

...

Keyword(s):

Fuel Cells ◽

Solid Oxide Fuel Cells ◽

Surface Structure ◽

First Principles ◽

Solid Oxide ◽

Oxide Fuel ◽

First Principles Study

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Unconventional Strategy to Anatase TiO2 Nanocrystals with Tunable Surface Chemistry via Liquid Crystalline Polyamides as a Functional Matrix

The Journal of Physical Chemistry C ◽

10.1021/acs.jpcc.7b08542 ◽

2017 ◽

Vol 121 (48) ◽

pp. 27111-27117

Author(s):

Chenxi Zhang ◽

Lingli Zhang ◽

Ning You ◽

Zhe Cui ◽

Peng Fu ◽

...

Keyword(s):

Surface Chemistry ◽

Liquid Crystalline ◽

Anatase Tio2 ◽

Tio2 Nanocrystals ◽

Functional Matrix

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First-Principles Atomistic Thermodynamics and Configurational Entropy

Frontiers in Chemistry ◽

10.3389/fchem.2020.00757 ◽

2020 ◽

Vol 8 ◽

Author(s):

Christopher Sutton ◽

Sergey V. Levchenko

Keyword(s):

First Principles ◽

Configurational Entropy ◽

Functional Materials ◽

Expansion Method ◽

Bulk Materials ◽

Cluster Expansion Method ◽

Particle Exchange ◽

Properties Of Materials ◽

Atomistic Thermodynamics ◽

Statistical Effects

In most applications, functional materials operate at finite temperatures and are in contact with a reservoir of atoms or molecules (gas, liquid, or solid). In order to understand the properties of materials at realistic conditions, statistical effects associated with configurational sampling and particle exchange at finite temperatures must consequently be taken into account. In this contribution, we discuss the main concepts behind equilibrium statistical mechanics. We demonstrate how these concepts can be used to predict the behavior of materials at realistic temperatures and pressures within the framework of atomistic thermodynamics. We also introduce and discuss methods for calculating phase diagrams of bulk materials and surfaces as well as point defect concentrations. In particular, we describe approaches for calculating the configurational density of states, which requires the evaluation of the energies of a large number of configurations. The cluster expansion method is therefore also discussed as a numerically efficient approach for evaluating these energies.

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