Mechanism and active site of photocatalytic water splitting on titania in aqueous surroundings

Zhao, Weina; Liu, Zhi-Pan

doi:10.1039/c3sc53385a

Cited by 95 publications

(78 citation statements)

References 68 publications

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“…Zero-point energies for the OER intermediates were obtained from the vibrational frequencies after structural optimization and those of free gas-phase molecules were obtained from thermodynamics database [32][33][34][35][36][37]. While for the intermediates adsorbed on the surface, the entropy was set to zero since intermediates lose the translational and rotational degrees of freedom upon adsorption.…”

Section: Thermodynamics and Photocatalysis For Oermentioning

confidence: 99%

Mechanistic insight into the water photooxidation on pure and sulfur-doped g-C3N4 photocatalysts from DFT calculations with dispersion corrections

Lin

Gao

et al. 2015

Journal of Molecular Catalysis A: Chemical

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Section: Thermodynamics and Photocatalysis For Oermentioning

confidence: 99%

Mechanistic insight into the water photooxidation on pure and sulfur-doped g-C3N4 photocatalysts from DFT calculations with dispersion corrections

Lin

Gao

et al. 2015

Journal of Molecular Catalysis A: Chemical

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“…the band gap and the valence band position relative to the H + /H 2 and H 2 O/O 2 levels). 26 Thus, great challenges exist for the computation of photocatalytic reaction kinetics as driven by excess holes/electrons accumulated on the catalyst surfaces. Using the projected augmented wave (PAW) method…”

Section: Introductionmentioning

confidence: 99%

C-, N-, S-, and Fe-Doped TiO₂ and SrTiO₃ Nanotubes for Visible-Light-Driven Photocatalytic Water Splitting: Prediction from First Principles

et al. 2015

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The ground state electronic structure and the formation energies of both TiO 2 and SrTiO 3 nanotubes (NTs) containing C O , N O , S O , and Fe Ti substitutional impurities are studied using first-principles calculations. We observe that N and S dopants in TiO 2 NTs lead to an enhancement of their visible-light-driven photocatalytic response, thereby increasing their ability to split H 2 O molecules. The differences between the highest occupied and lowest unoccupied impurity levels inside the band gap (HOIL and LUIL, respectively) are reduced in these defective nanotubes down to 2.4 and 2.5 eV for N and S doping, respectively. The band gap of an N O +S O co-doped titania nanotube is narrowed down to 2.2 eV (while preserving the proper disposition of the gap edges relatively to the reduction and oxidation potentials, so that HOIL < O 2 /H 2 O < H + /H 2 < LUIL ), thus decreasing the photon energy required for splitting of H 2 O molecule. For C-and Fe-doped TiO 2 NTs, some impurity levels lie in the interval between both redox potentials, which would lead to electron-hole recombination. Our calculations also reveal in sulfur-doped SrTiO 3 NTs a suitable band distribution for the oxygen evolution reaction, although the splitting of water molecules would be hardly possible due to an unsuitable conduction band position for the hydrogen reduction reaction. KeywordsDensity Functional Theory, SrTiO 3 and TiO 2 nanotubes, single-and double-atom dopants, atomic structure, electronic structure, photocatalytic properties. the influence of solar light on semiconducting photoelectrodes in aqueous electrolyte is a potentially clean and renewable source for hydrogen fuel. The process is often considered as artificial photosynthesis, and as such is an attractive and challenging research topic in the field of chemistry and renewable energy. 1-3The efficiency of the water splitting reactions 4 depends on the relative position of the semiconductor band edges (hole and electron energies) with respect to the redox levels, which are defined as measure of the affinity of the semiconducting substance for electrons (its electronegativity) compared with hydrogen. Redox couples in electrochemical reactions are characterized by molecules or ions in a solution which can be reduced and oxidized by a pure electron transfer. 5 This requires the semiconductors to exhibit a proper band alignment relative to the water redox potentials, e.g., the conduction band minimum of the p-type photocathode should be higher than the water reduction potential H + /H 2 , while the valence band maximum of the n-type photoanode, should be lower than the water oxidation potential O 2 /H 2 O. 6 Major limitations for the solar light conversion by photocatalysis relate to the band gap position in the corresponding photocatalytic materials and their stability in an aqueous environment.A number of binary and ternary metal oxide semiconductors have been intensively studied so far. 3,4,6 SrTiO 3 and, especially, TiO 2 (which distinguishes itself due to its superior chemica...

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“…Unfortunately, continuous curved surface has been scarcely discovered in artificial single crystals. As an important semiconductor, TiO 2 crystals have attracted intense research interests owing to its potential applications in a wide range of fields such as catalysis, photovoltaic cells, photochromic devices and gas sensors [17][18][19][20][21][22][23][24][25][26][27][28] . For TiO 2 crystals in the anatase phase, the equilibrium shape built through Wulff construction is a slightly truncated tetragonal bipyramid enclosed by eight thermodynamically stable {101} facets and two {001} facets [29][30][31] .…”

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confidence: 99%

Titania single crystals with a curved surface

et al. 2014

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Owing to its scientific and technological importance, crystallization as a ubiquitous phenomenon has been widely studied over centuries. Well-developed single crystals are generally enclosed by regular flat facets spontaneously to form polyhedral morphologies because of the well-known self-confinement principle for crystal growth. However, in nature, complex single crystalline calcitic skeleton of biological organisms generally has a curved external surface formed by specific interactions between organic moieties and biocompatible minerals. Here we show a new class of crystal surface of TiO 2 , which is enclosed by quasi continuous high-index microfacets and thus has a unique truncated biconic morphology. Such single crystals may open a new direction for crystal growth study since, in principle, crystal growth rates of all facets between two normal {101} and {011} crystal surfaces are almost identical. In other words, the facet with continuous Miller index can exist because of the continuous curvature on the crystal surface.

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Mechanism and active site of photocatalytic water splitting on titania in aqueous surroundings

Abstract: Photocatalytic water oxidation is both phase and surface structure-sensitive due to the heat-driven first-step of O–H bond breaking.

Cited by 95 publications

References 68 publications

Mechanistic insight into the water photooxidation on pure and sulfur-doped g-C3N4 photocatalysts from DFT calculations with dispersion corrections

Mechanistic insight into the water photooxidation on pure and sulfur-doped g-C3N4 photocatalysts from DFT calculations with dispersion corrections

C-, N-, S-, and Fe-Doped TiO₂ and SrTiO₃ Nanotubes for Visible-Light-Driven Photocatalytic Water Splitting: Prediction from First Principles

Titania single crystals with a curved surface

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Mechanism and active site of photocatalytic water splitting on titania in aqueous surroundings

Abstract: Photocatalytic water oxidation is both phase and surface structure-sensitive due to the heat-driven first-step of O–H bond breaking.

Cited by 95 publications

References 68 publications

Mechanistic insight into the water photooxidation on pure and sulfur-doped g-C3N4 photocatalysts from DFT calculations with dispersion corrections

Mechanistic insight into the water photooxidation on pure and sulfur-doped g-C3N4 photocatalysts from DFT calculations with dispersion corrections

C-, N-, S-, and Fe-Doped TiO2 and SrTiO3 Nanotubes for Visible-Light-Driven Photocatalytic Water Splitting: Prediction from First Principles

Titania single crystals with a curved surface

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C-, N-, S-, and Fe-Doped TiO₂ and SrTiO₃ Nanotubes for Visible-Light-Driven Photocatalytic Water Splitting: Prediction from First Principles