Probing the Optical Property and Electronic Structure of TiO₂Nanomaterials for Renewable Energy Applications

Abstract

CONTENTS 1. Introduction 9662 2. Light−Matter-Related Applications Including TiO 2 9665 2.1. TiO 2 as a Photocatalyst 9665 2.2. TiO 2 in Photovoltaics 9666 3. Correlation between Phase, Surface, and Photoelectric Properties 9666 4. Optical and Electronic Properties of TiO 2 9669 4.1. Survey through Recent and Past Theoretical Work on the Band Theory of TiO 2 9669 4.2. Evolution of the Electronic Structure upon Introduction of Impurity Elements into the Host Oxide Lattice 9670 4.3. Scalability of the Electronic Properties of Intrinsic and Doped TiO 2 9675 4.4. Hybrid-Structure TiO 2 for Enhanced Photoelectric Activity 9676 5. Overview of Recent Progress in the Tailoring of the Optical Properties of TiO 2 9677 5.1. Introduction of Impurity Elements into the Host TiO 2 Lattice 9677 5.1.1. Metal Doping 9677 5.1.2. Nonmetal Doping 9680 5.1.3. Codoping 9682 5.2. Heterostructure TiO 2 9683 5.3. Dye Sensitization for Enhanced Surface Characteristics 9686 5.4. Correlation between the Orientation of Crystal Facets and Optical Properties 9688 6. X-ray Spectroscopy on the Band Structure of TiO 2 9689 6.1. Soft X-ray Spectroscopy Enabling Characterization at the Atomistic Level 9689 6.2. General Spectroscopic Features of TiO 2 9691 6.3. Multilayer Architecture and Interfacial Electronic Structure 9693 7. Conclusions and Outlook 9695 Author Information 9696 Corresponding Author 9696 Notes 9696 Biographies 9696 Acknowledgments 9697 References 9697

Design of Novel Visible Light Active Photocatalyst Materials: Surface Modified TiO2

“…Since the pioneering work of Asahi et al in 2001 [29] there has been significant work devoted to studying substitutional doping of TiO2 to induce visible light absorption [19,21,26,30,31,32,33,34] ; the majority of work on doping has been with metal cations and more recent work has been on non-metal anion doping [19,20,21,29,30,31] . Since 2009, doping with both cations and anions, socalled co-doping [19,20,32,33,34] , has been well studied.…”

“…In developing TiO2 based photocatalysts, DFT level simulations have been widely used to understand experimental results or to attempt to predict the properties of doped TiO2 [21,[29][30][31][32][33][34] .…”

Brookite: Nothing New under the Sun?

“…While pure phase TiO 2 materials are extensively investigated for fundamental studies, mixed phase TiO 2 materials have been shown to provide enhanced photocatalytic performances, due to charge transfer across the interface of different phases [73]. For instance, the widely investigated TiO 2 Degussa P25, used as a standard in the majority of TiO 2 -related studies, is a mixture of anatase and rutile particles (anatase/rutile ratio~70:30) in which a synergistic effect of the two phases is ascribed to the spatial separation of photogenerated charge carriers [74].…”

Electronic Structure and Charge Transfer in the TiO2 Rutile (110)/Graphene Composite Using Hybrid DFT Calculations

“…1,15 Anchoring CdS to the surface of TiO 2 has been shown to increase photocatalytic activity notably and longevity to some extent, however issues with photocorrosion in particular pose a problem for potential industrial applications. 6,14,19 More recently, studies have been focussed on carbon-nanostructure/TiO 2 composite materials, 16,17,20,21 starting with carbon nanotubes (NTs) 22 27 following their isolation in the early 1990s. 28 Following a novel synthesis technique by Williams et al, 29 there has been a surge in interest in composites of TiO 2 with graphene.…”