Preparation of highly efficient Al-doped ZnO photocatalyst by combustion synthesis
TL;DR: In this article, Al-doped ZnO (AZO) photocatalysts with different Al concentrations (0.5e6.0 mol%) were prepared through a facile combustion method and followed by calcination at 500 � C for 3 h.
About: This article is published in Current Applied Physics.The article was published on 2013-06-01. It has received 294 citations till now. The article focuses on the topics: Fourier transform infrared spectroscopy & Absorption spectroscopy.
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TL;DR: This paper presents a critical review of recent achievements in the modification of ZnO photocatalyst for organic contaminants degradation and recommends improvements in the heterogeneous photocatalysis under UV/visible/solar illumination.
1,646 citations
TL;DR: In this paper, the photo-degradation mechanisms of persistent organic pollutants (POPs) and the recent progress in ZnO nanostructured fabrication methods including doping, heterojunction and modification techniques as well as improvements of ZnOs as a photocatalyst are reviewed.
Abstract: Persistent organic pollutants (POPs) are carbon-based chemical substances that are resistant to environmental degradation and may not be completely removed through treatment processes. Their persistence can contribute to adverse health impacts on wild-life and human beings. Thus, the solar photocatalysis process has received increasing attention due to its great potential as a green and eco-friendly process for the elimination of POPs to increase the security of clean water. In this context, ZnO nanostructures have been shown to be prominent photocatalyst candidates to be used in photodegradation owing to the facts that they are low-cost, non-toxic and more efficient in the absorption across a large fraction of the solar spectrum compared to TiO 2 . There are several aspects, however, need to be taken into consideration for further development. The purpose of this paper is to review the photo-degradation mechanisms of POPs and the recent progress in ZnO nanostructured fabrication methods including doping, heterojunction and modification techniques as well as improvements of ZnO as a photocatalyst. The second objective of this review is to evaluate the immobilization of photocatalyst and suspension systems while looking into their future challenges and prospects.
1,551 citations
TL;DR: In this article, the effect of dopant type, ionic size and its concentration on the crystal structure, electronic property and morphology of doped ZnO with a narrower band gap is reviewed systematically.
509 citations
TL;DR: In this paper, the use of TiO2 photocatalysis for water and waste treatment, treating contaminants of emerging concern (CECs), pesticides, endocrine disrupters (EDs) and bacteria using both UV and visible light irradiations is discussed.
Abstract: Advanced Oxidation technologies (AOTs) are gaining attention as an effective waste water treatment methodology capable of degrading diverse spectrum of recalcitrant organic contaminants and microbes. Undoubtedly, photocatalysis is a promising AOT to alleviate the problem of water pollution. Despite recent research into other photocatalysts (e.g. ZnO, ZnS, Semiconductor-Graphene composites, perovskites, MoS2, WO3 and Fe2O3), titanium dioxide (TiO2) remains the most popular photocatalyst due to its low cost, nontoxicity and high oxidising ability. Moreover, titania photocatalysts can easily be immobilized on various surfaces and be scaled up for large scale water treatment. The current review aims to highlight recent advancements in photocatalytic AOTs with main emphasis on TiO2 photocatalysis. This review also discusses the use of TiO2 photocatalysis for water and waste treatment, treating contaminants of emerging concern (CECs), pesticides, endocrine disrupters (EDs) and bacteria using both UV and visible light irradiations. It was concluded that with efficient photoreactor configuration and further studies on the photocatalyst regeneration, TiO2 photocatalysis is a viable option for the reclamation of agricultural/irrigational waste water. Novel doped photocatalysts such as ZnS-CuS-CdS, carbon spheres/CdS, g-C3N4-Au-CdS, ZnS-WS2-CdS, C3N4-CdS and Pd-Cr2O3-CdS have also been discussed. Finally, the advances in the actively studied metal organic framework based photocatalysts that are emerging as effective alternate for metal oxide based photocatalysts is also discussed in detail.
488 citations
TL;DR: The review provides a systematic and comprehensive understanding of the influence of different ZnO ETMs on PSCs performance and potentially motivates further development of Pscs by extending the knowledge of ZnNO-based P SCs to TiO2 -based PSC’s.
Abstract: Perovskite solar cells (PSCs) have developed rapidly over the past few years, and the power conversion efficiency of PSCs has exceeded 20%. Such high performance can be attributed to the unique properties of perovskite materials, such as high absorption over the visible range and long diffusion length. Due to the different diffusion lengths of holes and electrons, electron transporting materials (ETMs) used in PSCs play a critical role in PSCs performance. As an alternative to TiO2 ETM, ZnO materials have similar physical properties to TiO2 but with much higher electron mobility. In addition, there are many simple and facile methods to fabricate ZnO nanomaterials with low cost and energy consumption. This review focuses on recent developments in the use of ZnO ETM for PSCs. The fabrication methods of ZnO materials are briefly introduced. The influence of different ZnO ETMs on performance of PSCs is then reviewed. The limitations of ZnO ETM-based PSCs and some solutions to these challenges are also discussed. The review provides a systematic and comprehensive understanding of the influence of different ZnO ETMs on PSCs performance and potentially motivates further development of PSCs by extending the knowledge of ZnO-based PSCs to TiO2 -based PSCs.
316 citations
References
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TL;DR: Film and powders of TiO2-x Nx have revealed an improvement over titanium dioxide (TiO2) under visible light in optical absorption and photocatalytic activity such as photodegradations of methylene blue and gaseous acetaldehyde and hydrophilicity of the film surface.
Abstract: To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Films and powders of TiO 2- x N x have revealed an improvement over titanium dioxide (TiO 2 ) under visible light (wavelength 2 has proven to be indispensable for band-gap narrowing and photocatalytic activity, as assessed by first-principles calculations and x-ray photoemission spectroscopy.
11,402 citations
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09 Jun 2013
TL;DR: In this article, X-Rays and Diffraction Lattices and Crystal Structures and Hexagonal Structures are used for X-Ray Diffraction Experimental Modules: Crystal structure determination, I: Cubic Structures Crystal Structure Determination, II: Hexagonal structures Precise Lattice Parameter Measurements Phase Diagram Determination Detection of Long-Range Ordering Determination of Crystallite Size and Lattite Strain Quantitative Analysis of Powder Mixtures Identification of an Unknown Specimen: Appendices: Plane-Spacing Equations and Unit
Abstract: Basics: X-Rays and Diffraction Lattices and Crystal Structures Practical Aspects of X-Ray Diffraction Experimental Modules: Crystal Structure Determination, I: Cubic Structures Crystal Structure Determination, II: Hexagonal Structures Precise Lattice Parameter Measurements Phase Diagram Determination Detection of Long-Range Ordering Determination of Crystallite Size and Lattice Strain Quantitative Analysis of Powder Mixtures Identification of an Unknown Specimen: Appendices: Plane-Spacing Equations and Unit Cell Volumes Quadratic Forms of Miller Indices for the Cubic System Atomic and Ionic Scattering Factors of Some Selected Elements Summary of Structure Factor Calculations Mass Absorption Coefficients mu/rho (cm2/g) and Densities rho (g/cm3) of Some Selected Elements Multiplicity Factors Lorentz-Polarization Factor Physical Constants and Conversion Factors JCPDS-ICDD Card Numbers for Some Common Materials Index
1,594 citations
TL;DR: In this article, the photocatalytic activity of commercial ZnO powder has been investigated and compared with that of Degussa P25 TiO2 in terms of surface area, particle size and crystallinity.
1,458 citations
TL;DR: In this article, the authors have synthesized chemically modified titanium dioxide photocatalysts in which S (S4+) substitutes for some of the lattice titanium atoms, which showed strong absorption for visible light and high activities for degradation of methylene blue, 2-propanol in aqueous solution and partial oxidation of adamantane under irradiation at wavelengths longer than 440nm.
Abstract: Although titanium dioxide photocatalysts having anatase phase are a promising substrate for photodegradation of pollutants in water and air, their photocatalytic activities show only under ultraviolet (UV) light. For us to utilized a wide range of incident light such as solar light, development of the photocatalysts whose activities show under visible light is one of the most important strategies. We have synthesized chemically modified titanium dioxide photocatalysts in which S (S4+) substitutes for some of the lattice titanium atoms. They show strong absorption for visible light and high activities for degradation of methylene blue, 2-propanol in aqueous solution and partial oxidation of adamantane under irradiation at wavelengths longer than 440 nm. The oxidation state of the S atoms incorporated into the TiO2 particles is determined to be mainly S4+ from X-ray photoelectron spectra (XPS) spectra.
1,226 citations
TL;DR: Experiments combined with the density functional theory (DFT) calculation have been performed to understand the underlying photocatalysis mechanism of the nitrogen-doped titania nanobelts, finding that nitrogen doping allows visible-light-responsive photocatalytic activity but lowers UV- light-responsive photochemical activity.
Abstract: Experiments combined with the density functional theory (DFT) calculation have been performed to understand the underlying photocatalysis mechanism of the nitrogen-doped titania nanobelts. Nitrogen-doped anatase titania nanobelts are prepared via hydrothermal processing and subsequent heat treatment in NH3. Both the nitrogen content and the oxygen vacancy concentration increase with increasing the NH3 treatment temperature. Nitrogen doping leads to an add-on shoulder on the edge of the valence band, the localized N 2p levels above the valence band maximum, and the 3d states of Ti3+ below the conduction band, which is confirmed by DFT calculation and X-ray photoelectron spectroscopy (XPS) measurement. Extension of the light absorption from the ultraviolet (UV) region to the visible-light region arises from the N 2p levels near the valence band and from the color centers induced by the oxygen vacancies and the Ti3+ species. Nitrogen doping allows visible-light-responsive photocatalytic activity but lowers U...
1,098 citations