Atomic and electronic structures of Mg-doped perfect SrTiO3 and crystals containing oxygen vacancies from first principles

Zeng, Wen; Liu, Tian-mo; Lv, Chengling; Liu, Dejun

doi:10.1016/j.physb.2011.01.042

Cited by 13 publications

(5 citation statements)

References 27 publications

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“…SrTiO 3 is an ABO 3 ‐type perovskite oxide containing an alkaline‐earth cation on the A site and a tetravalent transient‐metal cation on the B site . For these structures it is usually accepted that introducing new heteroatoms on either an A or B site will lead to changes in 3d electron interactions, eventually tuning the valence state and electronic structure of the perovskite material . For example, through tuning the La 3+ /Sr 2+ ratio in La 1− x Sr x BO 3 and La 1− x Sr x BO 4 (B=Fe, Co, Mn, or Ni) oxides, Patzke and co‐workers demonstrated that even a transition from insulating to metal‐like behavior can be achieved.…”

Section: Introductionmentioning

confidence: 99%

“…For example, through tuning the La 3+ /Sr 2+ ratio in La 1− x Sr x BO 3 and La 1− x Sr x BO 4 (B=Fe, Co, Mn, or Ni) oxides, Patzke and co‐workers demonstrated that even a transition from insulating to metal‐like behavior can be achieved. Hence, as a typical perovskite oxide, SrTiO 3 is susceptible to tuning of its chemical and physical properties by altering its composition . Naturally introducing new heteroatoms can also be expected to drastically alter the capabilities of SrTiO 3 in photocatalytic water splitting.…”

Section: Introductionmentioning

confidence: 99%

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Promoting Photocatalytic Overall Water Splitting by Controlled Magnesium Incorporation in SrTiO₃ Photocatalysts

et al. 2017

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SrTiO3 is a well‐known photocatalyst inducing overall water splitting when exposed to UV irradiation of wavelengths <370 nm. However, the apparent quantum efficiency of SrTiO3 is typically low, even when functionalized with nanoparticles of Pt or Ni@NiO. Here, we introduce a simple solid‐state preparation method to control the incorporation of magnesium into the perovskite structure of SrTiO3. After deposition of Pt or Ni@NiO, the photocatalytic water‐splitting efficiency of the Mg:SrTiOx composites is up to 20 times higher compared to SrTiO3 containing similar catalytic nanoparticles, and an apparent quantum yield (AQY) of 10 % can be obtained in the wavelength range of 300–400 nm. Detailed characterization of the Mg:SrTiOx composites revealed that Mg is likely substituting the tetravalent Ti ion, leading to a favorable surface–space–charge layer. This originates from tuning of the donor density in the cubic SrTiO3 structure by Mg incorporation and enables high oxygen‐evolution rates. Nevertheless, interfacing with an appropriate hydrogen evolution catalyst is mandatory and non‐trivial to obtain high‐performance in water splitting.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Promoting Photocatalytic Overall Water Splitting by Controlled Magnesium Incorporation in SrTiO₃ Photocatalysts

et al. 2017

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“…Earlier reports suggest that the removal of one oxygen atom should introduce n-type carriers in SrTiO 3 and the Fermi level shifts into the conduction band, giving rise to a semiconductorto-metal transition. 47,53 In the present study, oxygen vacancy shifts the Fermi level into the CB with the occupied Ti−O hybrid states lying below and at E F , separated from the rest of the CB by a 0.5 eV gap. Both references did not report this gap in CB.…”

Section: Acsmentioning

confidence: 54%

Probing Photoexcited Charge Carrier Trapping and Defect Formation in Synergistic Doping of SrTiO₃

Koshi

Murthy

Chakraborty

et al. 2021

ACS Appl. Energy Mater.

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Strontium titanate (SrTiO3) is widely used as a promising photocatalyst due to its unique band edge alignment with respect to the oxidation and reduction potential corresponding to oxygen evolution reaction and hydrogen evolution reaction. However, further enhancement of the photocatalytic activity in this material could be envisaged through the effective control of oxygen vacancy states. This could substantially tune the photoexcited charge carrier trapping under the influence of elemental functionalization in SrTiO3, corresponding to the defect formation energy. The charge trapping states in SrTiO3 decrease through the substitutional doping in Ti sites with p-block elements like Aluminum (Al) with respect to the relative oxygen vacancies. With the help of electronic structure calculations based on density functional theory (DFT) formalism, we have explored the synergistic effect of doping with both Al and Iridium (Ir) in SrTiO3 from the perspective of defect formation energy, band edge alignment, and the corresponding charge carrier recombination probability to probe the photoexcited charge carrier trapping that primarily governs the photocatalytic water splitting process. We have also systematically investigated the ratio-effect of Ir:Al functionalization on the position of acceptor levels lying between Fermi and conduction band in oxygen deficient SrTiO3, which governs the charge carrier recombination and therefore the corresponding photocatalytic efficiency.

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“…When ST was loaded with CdS, Fermi energy level entered the conduction band with the behavior of changing from semiconductor to metal. [ 44 ] Relative to ST, the valence band moved toward the high energy region, and the bandgap decreased to 1.17 eV. Figure a shows the calculation total density of states (TDOS) and partial density of states (PDOS) of STC heterojunction.…”

Section: Resultsmentioning

confidence: 99%

Oxygen Vacancies‐Induced Dendritic SrTiO₃/CdS p–n Heterostructures Photocatalyst for Ultrahigh Hydrogen Evolution

Yu,

Li,

Duan

et al. 2023

Solar RRL

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Generally, hydrogen is regarded as one of the cleanest green energy sources, which can replace fossil fuels in the future due to its efficient energy release and zero-emission characteristics. [1] Photocatalytic water splitting is a promising method of hydrogen energy production. [2] As one of the most important solar technologies, semiconductor photocatalytic hydrogen production has attracted the attention of many researchers because of its environmental friendliness, stability, and economy. [3] Photosynthesis of natural plants can convert solar energy into other biological energy. The large specific surface area of the branches facilitates adequate photosynthesis, while it also requires the outside world to provide the necessary raw materials, such as dewdrops that can provide water for plants. However, there are still many challenges in the actual photocatalytic process. For example, the faster-photogenerated electron and hole complexation rates reduce the efficiency of photocatalysis, which in turn limits the practical applications of photocatalysis. [4,5] For this reason, numerous modification strategies including metal or nonmetal doping, [6,7] loading cocatalysts, [8] and construction of heterostructures [9,10] have been explored to improve photocatalytic efficiency, but there is still a huge potential for the development of lowering the carrier complexation rate in photocatalysis. Therefore, it is necessary to develop new methods to improve photocatalytic performance.SrTiO 3 is a perovskite oxide, which has a suitable band structure, high stability, superb electronic and optical performance, low toxicity, and inexpensive. [11,12] However, the broadband gap (%3.2 eV) of SrTiO 3 allows to make it merely absorb UV light, and the fast recombination of photo-generated charges carriers leads to a low usage rate of solar energy. [13] Oxygen vacancies can avoid the rapid recombination of photogenerated carriers and provide trapping sites at the same time. [14] Noticeably, oxygen vacancies can not only build a surface energy state but also expand the light absorbance to lower energy wavelengths. [15] Zhou [16] et al. found that hydrogen-treated SrTiO 3 can produce H 2 under UV light in absence of cocatalyst, due to the formation of appropriate oxygen vacancies by synergistic interaction of hydroxylation. Tan [17] et al. prepared surface oxygen vacancies on SrTiO 3 by the reaction with NaBH 4 . However, the practical application of SrTiO 3 has been greatly limited due to the low amount of hydrogen production. As a result of, it is of great meaning to explore a simple method to improve the photocatalytic hydrogen performance of SrTiO 3 .As a member of the metal sulfide family, CdS has a suitable bandgap (E g = 2.3 eV) with strong visible light absorption. [18][19][20] The inherent defects of CdS limit its practical application, such as easy photocorrosion and the high recombination rate

show abstract

Atomic and electronic structures of Mg-doped perfect SrTiO3 and crystals containing oxygen vacancies from first principles

Cited by 13 publications

References 27 publications

Promoting Photocatalytic Overall Water Splitting by Controlled Magnesium Incorporation in SrTiO₃ Photocatalysts

Promoting Photocatalytic Overall Water Splitting by Controlled Magnesium Incorporation in SrTiO₃ Photocatalysts

Probing Photoexcited Charge Carrier Trapping and Defect Formation in Synergistic Doping of SrTiO₃

Oxygen Vacancies‐Induced Dendritic SrTiO₃/CdS p–n Heterostructures Photocatalyst for Ultrahigh Hydrogen Evolution

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Atomic and electronic structures of Mg-doped perfect SrTiO3 and crystals containing oxygen vacancies from first principles

Cited by 13 publications

References 27 publications

Promoting Photocatalytic Overall Water Splitting by Controlled Magnesium Incorporation in SrTiO3 Photocatalysts

Promoting Photocatalytic Overall Water Splitting by Controlled Magnesium Incorporation in SrTiO3 Photocatalysts

Probing Photoexcited Charge Carrier Trapping and Defect Formation in Synergistic Doping of SrTiO3

Oxygen Vacancies‐Induced Dendritic SrTiO3/CdS p–n Heterostructures Photocatalyst for Ultrahigh Hydrogen Evolution

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Promoting Photocatalytic Overall Water Splitting by Controlled Magnesium Incorporation in SrTiO₃ Photocatalysts

Promoting Photocatalytic Overall Water Splitting by Controlled Magnesium Incorporation in SrTiO₃ Photocatalysts

Probing Photoexcited Charge Carrier Trapping and Defect Formation in Synergistic Doping of SrTiO₃

Oxygen Vacancies‐Induced Dendritic SrTiO₃/CdS p–n Heterostructures Photocatalyst for Ultrahigh Hydrogen Evolution