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Journal ArticleDOI

Lanthanide ions doped ZnO based photocatalysts

01 Nov 2021-Separation and Purification Technology (Elsevier)-Vol. 274, pp 118853
TL;DR: In this article, the influence of lanthanide ions dopant on the structure-optical properties of ZnO is discussed and the performance of Ln-ZnO towards the degradation of organic pollutants is discussed encompassing both the materials properties and photocatalytic reaction conditions under UV/visible and solar light.
About: This article is published in Separation and Purification Technology.The article was published on 2021-11-01. It has received 22 citations till now.
Citations
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Journal ArticleDOI
TL;DR: In this paper , the authors used sol-gel technology to synthesize pure ZnO and Rb-doped ZnOs nanoparticles, RbxZn1-xO-NPs.
Abstract: This article is dedicated to synthesizing pure ZnO and Rb-doped ZnO nanoparticles, RbxZn1-xO-NPs (x=0.0, 0.02, 0.04, 0.06 mol) using sol-gel technology. Synthesized samples have been characterized and studied utilizing X-ray...

22 citations

Journal ArticleDOI
TL;DR: In this paper , the effect of the synthesis method and conditions on the properties of ZnO is discussed, such as band gap, crystallite size, and morphology, depend on the synthesis methods and parameters employed.

11 citations

Journal ArticleDOI
TL;DR: In this paper , Dy3+:Zn2Ti3O8 nano-photocatalyst was applied to enhance the photocatalytic hydrogen generation activity from sodium borohydride hydrolysis reaction.

6 citations

Journal ArticleDOI
TL;DR: In this paper , six ZnO nanocrystals with the shapes of granule, flake, rod, porous flake and nanosheet-assembled flower were designed and synthesized to investigate the relationship between their photocatalytic activities and morphological features.

5 citations

Journal ArticleDOI
TL;DR: In this paper, a co-doped bulk Cd0.5Zn 0.5S (CZS) was fabricated by a simple hydrothermal process, and used for evaluating the catalytic activity for aquatic hydrogen production under visible light irradiation.
Abstract: Using ion doping to engineer sulfur vacancies over metal sulfides is an effective method to improve photocatalytic properties, such vacancies form the center of the electron-captured state to promote the separation and transfer of photogenerated carriers. In this research, Yb/Er co-doped bulk Cd0.5Zn0.5S (CZS) was fabricated by a one-step simple hydrothermal process, and used for evaluating the catalytic activity for aquatic hydrogen production under visible light irradiation. The results showed that the Cd0.5Zn0.5S:Yb(15%), Er obtained exhibited a higher efficient photocatalytic activity of hydrogen evolution, in which the efficiency of Cd0.5Zn0.5S:Yb(15%), Er (422.0 μmol g−1 h−1) was 2.7 times higher than that of bare Cd0.5Zn0.5S (154.7 μmol g−1 h−1). This can be attributed to the augmented active surface area, the broadened spectral absorption of visible light and the facilitation of the separated efficiency of the photogenerated carriers. This finding provides a simple way to activate the metal-chalcogenides with S-vacancies for optimizing the photocatalytic performance.

4 citations

References
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Journal ArticleDOI
TL;DR: In this article, the presence of metal ion dopants in the TiO_2 crystalline matrix significantly influences photoreactivity, charge carrier recombination rates, and interfacial electron-transfer rates.
Abstract: A systematic study of metal ion doping in quantum (Q)-sized (2-4 nm) TiO_2 colloids is performed by measuring their photoreactivities and the transient charge carrier recombination dynamics. The presence of metal ion dopants in the TiO_2 crystalline matrix significantly influences photoreactivity, charge carrier recombination rates, and interfacial electron-transfer rates. The photoreactivities of 21 metal ion-doped colloids are quantified in terms of both the conduction band electron reduction of an electron acceptor (CCl_4 dechlorination) and the valence band hole oxidation of an electron donor (CHCl_3 degradation). Doping with Fe^(3+), Mo^(5+), Ru^(3+), Os^(3+), Re^(5+), V^(4+), and Rh^(3+) at 0.1-0.5 at.% significantly increases the photoreactivity for both oxidation and reduction while Co^(3+) and Al^(3+) doping decreases the photoreactivity. The transient absorption signals upon laser flash photolysis (λ_(ex) = 355 nm) at λ = 600 nm are extended up to 50 ms for Fe^(3+)-, V^(4+)-, Mo^(5+)-, and Ru^(3+)-doped TiO_2 while the undoped Q-sized TiO_2 shows a complete "blue electron" signal decay within 200 μs. Co^(3+)- and Al^(3+)-doped TiO_2 are characterized by rapid signal decays with a complete loss of absorption signals within 5 μs. The quantum yields obtained during CW photolyses are quantitatively correlated with the measured transient absorption signals of the charge carriers. Photoreactivities are shown to increase with the relative concentration of trapped charge carriers. The photoreactivity of doped TiO_2 appears to be a complex function of the dopant concentration, the energy level of dopants within the TiO_2 lattice, their d electronic configuration, the distribution of dopants, the electron donor concentration, and the light intensity.

3,508 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used the Williamson-Hall analysis and size-strain plot method to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of ZnO-NPs.

1,784 citations

Journal ArticleDOI
TL;DR: This review encompasses several advancements made in these aspects of titania, and also some of the new physical insights related to the charge transfer events like charge carrier generation, trapping, detrapping, and their transfer to surface are discussed for each strategy of the modified titania to support the conclusions derived.
Abstract: Titania is one of the most widely used benchmark standard photocatalysts in the field of environmental applications. However, the large band gap of titania and massive recombination of photogenerated charge carriers limit its overall photocatalytic efficiency. The former can be overcome by modifying the electronic band structure of titania including various strategies like coupling with a narrow band gap semiconductor, metal ion/nonmetal ion doping, codoping with two or more foreign ions, surface sensitization by organic dyes or metal complexes, and noble metal deposition. The latter can be corrected by changing the surface properties of titania by fluorination or sulfation or by the addition of suitable electron acceptors besides molecular oxygen in the reaction medium. This review encompasses several advancements made in these aspects, and also some of the new physical insights related to the charge transfer events like charge carrier generation, trapping, detrapping, and their transfer to surface are d...

1,728 citations

Journal ArticleDOI
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

Journal ArticleDOI
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