Electronic Structures of S/C-Doped TiO2Anatase (101) Surface: First-Principles Calculations

Qili Chen,Bo Li,Kaihua He,Min Liu

doi:10.1155/2014/816234

Qili Chen, Bo Li + Show 2 more

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https://doi.org/10.1155/2014/816234

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Abstract

The electronic structures of sulfur (S) or carbon (C)-doped TiO2anatase (101) surfaces have been investigated by density functional theory (DFT) plane-wave pseudopotential method. The general gradient approximation (GGA) +U(Hubbard coefficient) method has been adopted to describe the exchange-correlation effects. All the possible doping situations, including S/C dopants at lattice oxygen (O) sites (anion doping), S/C dopants at titanium (Ti) sites (cation doping), and the coexisting of anion and cation doping, were studied. By comparing the formation energies, it was found that the complex of anion and cation doping configuration forms easily in the most range of O chemical potential for both S and C doping. The calculated density of states for various S/C doping systems shows that the synergistic effects of S impurities at lattice O and Ti sites lead a sharp band gap narrowing of 1.35 eV for S-doped system comparing with the pure TiO2system.

Highlights

Many researchers have paid much attention on titanium dioxide (TiO2)
It needs ultraviolet (UV) radiation to excite the electrons from valence band (VB) to conduction band (CB)
The computational calculations have been performed by density-functional theory (DFT) plane-wave pseudopotential method [14], as implemented in the CASTEP 5.0 codes [15]

Summary

Introduction

Many researchers have paid much attention on titanium dioxide (TiO2). As a promising photocatalytic semiconductor for environmental treatment, it has excellent functionality, long-term stability, and nanotoxicity [1]. TiO2 is a kind of wide band gap semiconductor (3.2 eV for anatase phase and 3.0 eV for rutile phase [2]). It needs ultraviolet (UV) radiation to excite the electrons from valence band (VB) to conduction band (CB). The energy of UV light accounts for only small fraction of the sunlight. How to enhance the ability of visible light (VIS) absorption of TiO2 is critical to enable the utility of TiO2 photocatalyst materials

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