Efficient Charge Carrier Separation in l-Alanine Acids Derived N-TiO2 Nanospheres: The Role of Oxygen Vacancies in Tetrahedral Ti4+ Sites

Chen, Yongjuan; X, Luo; Luo, Yao; Xu, Peiwen; He, Jiao; Jiang, Liang; Li, Junjie; Yan, Zhiying; Wang, Jiaqiang

doi:10.3390/nano9050698

Cited by 11 publications

(8 citation statements)

References 39 publications

(45 reference statements)

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“…The oxygen vacancies located at 0.75-1.18 eV below the conduction band edge are responsible for the long lifetime of the photoexcited carriers. [43][44][45]50] The introduction of more oxygen vacancies is also confirmed by comparing the temperature dependences of photoluminescence (PL) spectra from the samples, as shown in Figure 16. The PL spectra were measured at various sample temperatures with an excitation light of 313 nm in wavelength (4 eV in photon energy).…”

Section: Discussionmentioning

confidence: 73%

“…This suggests that the PAA contributes to reducing the concentration of residual charged carriers attributed to oxygen vacancies unintentionally present in TiO 2 . [43,44] The oxygen vacancies are known to act as shallow donors. [43][44][45] In the presence of UV irradiation, the conductivities of samples become larger because of UV-photoexcited carriers generated in the samples.…”

Section: Electrical Conductivitiesmentioning

confidence: 99%

“…[43,44] The oxygen vacancies are known to act as shallow donors. [43][44][45] In the presence of UV irradiation, the conductivities of samples become larger because of UV-photoexcited carriers generated in the samples. In particular, the UV-induced conductivity of plasma-assisted-annealed P-25 is larger than that of untreated P-25 NPs.…”

Section: Electrical Conductivitiesmentioning

confidence: 99%

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Photocatalytic Activity Enhancement of Anatase/Rutile‐Mixed Phase TiO₂ Nanoparticles Annealed with Low‐Temperature O₂ Plasma

Kawakami

Mimoto

Yanagiya

et al. 2021

Physica Status Solidi (a)

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Photodecomposition and photobactericidal activities of anatase/rutile-mixed phase TiO 2 nanoparticles annealed with low-temperature O 2 plasma are clarified by comparing them with those annealed in ambient air. The photocatalytic activities of plasma-assisted-annealed sample greatly enhance as compared with the untreated sample, under not only UV irradiation but also visible-light irradiation. The photocatalytic activities of air-annealed samples do not enhance under UV irradiation but enhance under visible-light irradiation. The enhanced photocatalytic activities due to the plasma-assisted annealing (PAA) originate from the increased photoexcited carrier concentration. This enhancement is discussed from PAA-induced characteristic factors. PAA facilitates the phase transformation to anatase, contributing directly to extending the photoexcited carrier lifetime. PAA introduces more oxygen vacancies, contributing to trapping more photogenerated electrons. PAA also introduces more bridging/terminal oxygen groups adsorbed on the surface, increasing the upward band-bending, the depletion layer width at the surface, and the charge transfer from rutile to anatase. These two introductions contribute to facilitating the separation of photoexcited carriers. Furthermore, PAA reduces the aggregate size of TiO 2 nanoparticles formed on the surface, contributing to increasing optical absorptions. More reactive oxygen species produced from the bridging/terminal oxygen groups by the photoexcited carriers will also enhance the photocatalytic activities.

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Section: Discussionmentioning

confidence: 73%

Section: Electrical Conductivitiesmentioning

confidence: 99%

Section: Electrical Conductivitiesmentioning

confidence: 99%

See 1 more Smart Citation

Photocatalytic Activity Enhancement of Anatase/Rutile‐Mixed Phase TiO₂ Nanoparticles Annealed with Low‐Temperature O₂ Plasma

Kawakami

Mimoto

Yanagiya

et al. 2021

Physica Status Solidi (a)

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“…In another study, Chen et al [110] investigated the decay kinetics of photogenerated electrons that result in recombination or carrier reactions in the synthesized N-doped TiO 2 samples using time-resolved infrared (IR) spectroscopy. The observed transient absorbance spectrum at 1910 cm −1 shown in Fig.…”

Section: Characterizations Of N-doped Tio 2 Photocatalystsmentioning

confidence: 99%

Visible Light-Responsive N-Doped TiO2 Photocatalysis: Synthesis, Characterizations, and Applications

Lian

Zhang

2021

Trans. Tianjin Univ.

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Photocatalysis based on semiconductors has recently been receiving considerable research interest because of its extensive applications in environmental remediation and renewable energy generation. Various semiconductor-based materials that are vital to solar energy utilization have been extensively investigated, among which titanium oxide (TiO2) has attracted considerable attention because of its exceptional physicochemical characteristics. However, the sluggish responsiveness to visible light in the solar spectrum and the inefficient separation of photoinduced electron–hole pairs hamper the practical application of TiO2 materials. To overcome the aforementioned serious drawbacks of TiO2, numerous strategies, such as doping with foreign atoms, particularly nitrogen (N), have been improved in the past few decades. This review aims to provide a comprehensive update and description of the recent developments of N-doped TiO2 materials for visible light-responsive photocatalysis, such as (1) the preparation of N-doped/co-doped TiO2 photocatalysts and (2) mechanistic studies on the reasons for visible light response. Furthermore, the most recent and significant advances in the field of solar energy applications of modified N-doped TiO2 are summarized. The analysis indicated the critical need for further development of these types of materials for the solar-to-energy conversion, particularly for water splitting purposes.

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“…Photocatalysis, as a potential route to relieving environmental and energy issues, has been intensively applied for pollutant degradation [1][2][3][4], water splitting [5][6][7], and solar energy conversion [8][9][10][11]. As a typical metal sulfide, ZnS, which has a large band gap (3.6~3.8 eV), exhibits excellent photocatalytic capacity, owing to its strong oxidation and high negative potentials of excited electrons [12,13].…”

Section: Introductionmentioning

confidence: 99%

N-Doped Carbon-Coated ZnS with Sulfur-Vacancy Defect for Enhanced Photocatalytic Activity in the Visible Light Region

et al. 2019

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In this work, N-doped carbon-coated ZnS with a sulfur-vacancy defect (ZnS@N-C) was performed for the visible-light-driven photodegradation of tetracycline hydrochloride (TCH). The obtained ZnS@N-C exhibited enhanced photocatalytic activity compared with ZnS for TCH removal. Among these ZnS@N-C composites, ZnS@N-C-3 with N-doped content of 3.01% (100 nm) presented the best visible-light photocatalytic activity and superior long-term photocatalytic stability after five cycle times for TCH removal in the visible light region. This may be ascribed to the interface between the N-doped carbon shell and ZnS with a sulfur-vacancy defect for efficient charge transfer and the restrained recombination of charge carriers. Electron spin resonance (ESR) results indicate that the ·O 2 radical plays a crucial role in the enhanced photocatalytic activity of ZnS@N-C-3. Nanomaterials 2019, 9, 1657 2 of 13 composites between carbon and semiconductors. To further enhance the electron transfer and extend the visible light harvesting region, carbon doped with N atoms can adjust the work function of carbon and induce charge delocalization [23-26]. Hsu et al. have reported that sandwich-like hydrogenated C-doped anatase TiO 2 nanocrystals/N-doped carbon dots@layer/rutile TiO 2 nanorod arrays have exhibited efficient photoelectron-chemical activity of water oxidation [27]. This may be attributed to the N-doped carbon dots being the photosensitizer of long wavelength light-harvesting and the N-doped carbon layer being the conductive layer of charge transport toward the current collector. Wang et al. have also confirmed that N-doped carbon dots/g-C 3 N 4 can enhance visible-light photo-degradation activity for indomethacin due to the efficient charge separation and band gap narrowing of N-doped carbon dots [28]. Core-shell structured ZnO@N-doped carbon can efficiently adsorb and photodegrade methylene blue in the visible light region [29]. Electrons generated from nitrogen are transferred from the N-doped carbon surface to adsorbed oxygen, forming reactive radicals in the photocatalytic system [30-34]. In addition, surface polarity of N-doped carbon can promote dispersion in aqueous solution. However, few works have focused on the enhanced photocatalytic activity of ZnS with sulfur-vacancy defects using N-doped carbon coating. This work focuses on the synthesis of ZnS with an N-doped carbon coating (ZnS@N-C) and its sulfur-vacancy effect on visible-light photocatalytic activity for the removal of tetracycline hydrochloride (TCH). Reported photocatalysts such as CuInS 2 /Mg(OH) 2 [35], ZnIn 2 S 4 /BiPO 4 [36], AgBr/Bi 2 WO 6 [37], BiOI/g-C 3 N 4 /CeO 2 [38], and TiO 2 / BiOCl [39] are efficient heterojunctions for the visible-light-driven degradation of TCH. Differently from these compositions, N-doped carbon serves as the electron capture, facilitating the separation of electron-hole pairs. In this strategy, N-doped carbon is generated from the decomposition of cyanamide and coated on the surface of ZnS nano-particles, which are further tr...

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Efficient Charge Carrier Separation in l-Alanine Acids Derived N-TiO2 Nanospheres: The Role of Oxygen Vacancies in Tetrahedral Ti4+ Sites

Cited by 11 publications

References 39 publications

Photocatalytic Activity Enhancement of Anatase/Rutile‐Mixed Phase TiO₂ Nanoparticles Annealed with Low‐Temperature O₂ Plasma

Photocatalytic Activity Enhancement of Anatase/Rutile‐Mixed Phase TiO₂ Nanoparticles Annealed with Low‐Temperature O₂ Plasma

Visible Light-Responsive N-Doped TiO2 Photocatalysis: Synthesis, Characterizations, and Applications

N-Doped Carbon-Coated ZnS with Sulfur-Vacancy Defect for Enhanced Photocatalytic Activity in the Visible Light Region

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Efficient Charge Carrier Separation in l-Alanine Acids Derived N-TiO2 Nanospheres: The Role of Oxygen Vacancies in Tetrahedral Ti4+ Sites

Cited by 11 publications

References 39 publications

Photocatalytic Activity Enhancement of Anatase/Rutile‐Mixed Phase TiO2 Nanoparticles Annealed with Low‐Temperature O2 Plasma

Photocatalytic Activity Enhancement of Anatase/Rutile‐Mixed Phase TiO2 Nanoparticles Annealed with Low‐Temperature O2 Plasma

Visible Light-Responsive N-Doped TiO2 Photocatalysis: Synthesis, Characterizations, and Applications

N-Doped Carbon-Coated ZnS with Sulfur-Vacancy Defect for Enhanced Photocatalytic Activity in the Visible Light Region

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Product

Resources

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Photocatalytic Activity Enhancement of Anatase/Rutile‐Mixed Phase TiO₂ Nanoparticles Annealed with Low‐Temperature O₂ Plasma

Photocatalytic Activity Enhancement of Anatase/Rutile‐Mixed Phase TiO₂ Nanoparticles Annealed with Low‐Temperature O₂ Plasma