Local Interfacial Structure Influences Charge Localization in Titania Composites: Beyond the Band Alignment Paradigm

Nolan, Michael; Deskins, N. Aaron; Schwartzenberg, Kevin C.; Gray, Kimberly A.

doi:10.1021/acs.jpcc.5b12326

Cited by 31 publications

(20 citation statements)

References 54 publications

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“…16(A)) and r-(001)/a-(100) ( Fig. 16(B)) boundaries; these two boundary models were then used for DFT + U computations [216]. A disordered interfacial region is present at the a-TiO 2 /r-TiO 2 junction after geometrical relaxation.…”

Section: Charge Carrier Localization At Nanoclusters and Boundariesmentioning

confidence: 99%

Intrinsic intermediate gap states of TiO2 materials and their roles in charge carrier kinetics

Liu

Zhao

et al. 2019

Journal of Photochemistry and Photobiology C: Photochemistry Re

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Titanium dioxide (TiO 2) is regarded as an important prototype photocatalytic material for several decades. The charge carrier kinetics determines the photocatalytic properties of TiO 2 materials; this is found to be greatly dependent on electronic structures. It has been revealed that the intrinsic intermediate gap states (intrinsic GSs) play a significant role in charge carrier kinetics that drive the photocatalytic processes of TiO 2 materials, which are not well summarized until now. Motivated by this thought, the purpose of this review focuses on physiochemical science of the intrinsic GSs of TiO 2 materials and their important role in charge carrier kinetics. We first give a summary on the chemical resources of the intrinsic GSs in TiO 2 and their physiochemical nature. Their general energy distribution, charge carrier population, and the associated thermodynamic properties are also elaborated from an overall viewpoint. We further carefully summarize and compare the experimental studies on the energy and the density distribution of the intrinsic GSs and discuss the associated chemical resources and charge carrier localizations. Trapping is the dominant function of intrinsic GSs in the charge carrier kinetics of TiO 2 materials. The significant effect of trapping on the transport, recombination, and interfacial transfer of charge carriers are also comprehensive summarized. Furthermore, the effects of charge carrier kinetics on photocatalytic performances are also discussed to some extents. Because of the importance of intrinsic GSs in modulating charge carrier kinetics, it is expected to increase the photocatalytic activity by engineering the intrinsic GSs, not only for TiO 2 materials, but also for the other semiconductor photocatalysts.

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Section: Charge Carrier Localization At Nanoclusters and Boundariesmentioning

confidence: 99%

Intrinsic intermediate gap states of TiO2 materials and their roles in charge carrier kinetics

Liu

Zhao

et al. 2019

Journal of Photochemistry and Photobiology C: Photochemistry Re

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“…In 2016, Nolan et al . used PBE+U calculations to reveal that the interfacial region in TiO 2 rutile/anatase junction structure is disordered and different from pure rutile and anatase phase . It was shown that electrons localize in undercoordinated Ti atoms in the interfaces, which are important in the high performance of mixed‐phase TiO 2 .…”

Section: Fabrication Of Junction Structurementioning

confidence: 99%

A Theoretical Perspective on Charge Separation and Transfer in Metal Oxide Photocatalysts for Water Splitting

Zhou

Dong

2019

ChemCatChem

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Semiconductor‐based photocatalytic decomposition of water is one of the most promising techniques to produce clean and renewable energy in the future. Photogenerated charge separation and transfer is considered as one of the crucial steps controlling the conversion efficiency of solar energy in heterogeneous photocatalysis. Many experimental methods have been developed to enhance the efficiency of this process, such as fabricating junction structures, manipulating exposed facets, and loading suitable cocatalysts. Besides a variety of time and spatial resolved spectroscopic techniques, density functional theory calculations have been widely used to explore the photoinduced charge dynamics due to the advances of relevant theory and methodologies along with the improved computer performance. This article reviews recent theoretical researches mainly by means of density functional theory calculations in the charge separation and transportation in metal oxide photocatalytic systems. We introduce some common theoretical and computational methods for investigating physicochemical properties of photocatalytic materials, discuss the charge mobility in bulk and surface of semiconductors, the interfacial charge transfer in junction structures, and the role of cocatalysts in complex photocatalysts, and then evaluate potential research directions for superior photocatalytic systems on the basis of computational investigation and theoretical comprehension of intrinsic properties.

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“…(Diebold, 2003; Yu et al, 2003; Stevanovic et al, 2012; Ronca et al, 2013; Amano et al, 2016; Macounová et al, 2017), a complete understanding of the electronic and optical properties of TiO 2 remains elusive, despite a number of experimental and theoretical studies that have been conducted. For example, the relative band edge positions between the rutile and anatase phases are still under debate (Li and Gray, 2007; Scanlon et al, 2013; Zhang et al, 2014; Nolan et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure and Band Alignments of Various Phases of Titania Using the Self-Consistent Hybrid Density Functional and DFT+U Methods

et al. 2019

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To understand, and thereby rationally optimize photoactive interfaces, it is of great importance to elucidate the electronic structures and band alignments of these interfaces. For the first-principles investigation of these properties, conventional density functional theory (DFT) requires a solution to mitigate its well-known bandgap underestimation problem. Hybrid functional and Hubbard U correction are computationally efficient methods to overcome this limitation, however, the results are largely dependent on the choice of parameters. In this study, we employed recently developed self-consistent approaches, which enable non-empirical determination of the parameters, to investigate TiO2 interfacial systems—the most prototypical photocatalytic systems. We investigated the structural, electronic, and optical properties of rutile and anatase phases of TiO2. We found that the self-consistent hybrid functional method predicts the most reliable structural and electronic properties that are comparable to the experimental and high-level GW results. Using the validated self-consistent hybrid functional method, we further investigated the band edge positions between rutile and anatase surfaces in a vacuum and electrolyte medium, by coupling it with the Poisson-Boltzmann theory. This suggests the possibility of a transition from the straddling-type to the staggered-type band alignment between rutile and anatase phases in the electrolyte medium, manifested by the formation of a Stern-like layer at the interfaces. Our study not only confirms the efficacy of the self-consistent hybrid functional method by reliably predicting the electronic structure of photoactive interfaces, but also elucidates a potentially dramatic change in the band edge positions of TiO2 in aqueous electrolyte medium which can extensively affect its photophysical properties.

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Local Interfacial Structure Influences Charge Localization in Titania Composites: Beyond the Band Alignment Paradigm

Cited by 31 publications

References 54 publications

Intrinsic intermediate gap states of TiO2 materials and their roles in charge carrier kinetics

Intrinsic intermediate gap states of TiO2 materials and their roles in charge carrier kinetics

A Theoretical Perspective on Charge Separation and Transfer in Metal Oxide Photocatalysts for Water Splitting

Electronic Structure and Band Alignments of Various Phases of Titania Using the Self-Consistent Hybrid Density Functional and DFT+U Methods

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