Synthesis, characterization and visible-light driven photocatalysis by differently structured CdS/ZnS sandwich and core–shell nanocomposites

Qutub, Nida; Pirzada, Bilal Masood; Umar, Khalid; Mehraj, Owais; Muneer, M.; Sabir, Suhail

doi:10.1016/j.physe.2015.06.023

Cited by 46 publications

(11 citation statements)

References 48 publications

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“…The appearance of peaks related to alone CdS and absence of peaks corresponding to core (ZnS) suggest the creation of the core/shell structure of the reverse ZnS@CdS type‐I QDs. This is good in accordance with the previous report on core@shell nanostructures, that as the shell diameter extends, the shell diffraction pattern prevails . In addition, the diffraction peaks in ZnS@CdS are shifted to the lower angle compared with that of CdS, which further confirm the formation CdS shell on the cubic zinc blende phase of ZnS core.…”

Section: Resultssupporting

confidence: 92%

Excitons with Reverse Rectifying Characteristics for Superior Solar Photocatalysis

Samadi‐Maybodi

Shariati

2018

ChemistrySelect

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This study demonstrates an inverted energy‐gradient hybrid nanoparticle architecture that supports the formation of 2D excitons in the nanoshell domain. The developed geometry places a wide‐gap semiconductor quantum dot (ZnS, Eg= 3.68 eV) at the core of the nanocomposite particle in order to funnel the photoinduced energy into the low‐gap (CdS, Eg= 2.42 eV) shell layer. This inverted band regime helps to extract the photogenerated excitons into the shell and hence increases the exciton transport quantum efficiency, hereby leading to the superior photocatalytic efficiency for photoredox reactions over the nanohybrid. To demonstrate bandgap engineering and photoinduced charge carrier delocalization, we employed steady‐state and time‐resolved emission and absorption techniques in the presence and absence of an electron quencher (4‐nitrophenol) and hole quencher (4‐methoxyphenol). The significant suppression of band‐edge emissions and the decrement of the fluorescence lifetimes demonstrated the key role of nanoshell on the transfer of photogenerated charge carriers from core to the surface of the photocatalyst. Detailed investigations of the photocatalytic activity of ZnS@CdS and kinetic study of the reactions were also carried out under solar radiation. The contribution of O2•− and •OH to photocatalytic reactions revealed respectively via luminol chemiluminescence and terephthalic acid photoluminescence techniques.

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Section: Resultssupporting

confidence: 92%

Excitons with Reverse Rectifying Characteristics for Superior Solar Photocatalysis

Samadi‐Maybodi

Shariati

2018

ChemistrySelect

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“…The complete absence of core (magnetite) peaks and the presence of shell (CdS) peaks indicate the core–shell structure of the magnetite@CdS NHs. This is in good agreement with previous reports on core–shell systems, for which, as the shell diameter increases, the diffraction pattern of the shell material prevails . Additionally, the observed shift in the 2 θ position of the XRD reflection peaks of Fe 3 O 4 @CdS NHs to higher reflection angles can be correlated with the decrease in interplanar separation of the crystal lattice and formation of compressive strain in the samples, owing to the Miller mismatch between Fe 3 O 4 and CdS.…”

Section: Resultsmentioning

confidence: 99%

“…This is in good agreement with previousr eports on core-shell systems, for which,a st he shell diameter increases, the diffraction pattern of the shell material prevails. [29,30] Additionally,t he observed shift in the 2 q position of the XRD reflection peaks of Fe 3 O 4 @CdS NHs to higher reflection anglesc an be correlated with the decrease in interplanar separation of the crystal lattice and formation of compressive strain in the samples, owing to the Miller mismatch between Fe 3 O 4 and CdS. In the proposed core-shell NHs, ac ompressive strain is inducedo nt he CdS crystal planes by the Fe 3 O 4 crystal with smaller d spacing.…”

Section: Resultsmentioning

confidence: 99%

Magnetically Separable Fe₃O₄@CdS Type‐II Nanohybrids with Excellent Photocatalytic Activity and Antibacterial Properties

2018

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A magnetically separable Fe3O4@CdS type‐II core–shell nanohybrid (NH) photocatalyst, with excellent antibacterial properties and photocatalytic activity, was synthesized and characterized by means of structural, elemental, and morphological analyses. Steady‐state and time‐resolved emission and absorption spectroscopy were also exploited to realize the location of charge‐carrier wave functions in the NHs. The antibacterial activity of NHs was then evaluated against Escherichia coli (1.4×108 CFU mL−1; CFU=colony forming units) and Staphylococcus saprophyticus (1.2×108 CFU mL−1) as model strains of Gram‐negative and ‐positive microbes. Compared with CdS and Fe3O4, the as‐synthesized Fe3O4@CdS composite exhibited highly improved bactericidal activity and recyclability. Concentration values of 5.0 and 4.0 mg mL−1 were required for Fe3O4@CdS NHs to inhibit the growth of E. coli and S. saprophyticus, respectively. The contribution of OH. radicals to photocatalysis at the Fe3O4@CdS surface was also considered. Moreover, thiobarbituric acid reactive substances and protein carbonyl assay protocols have been exploited to monitor levels of oxidative damage to lipids and proteins in cells. Additionally, the photocatalytic activity of Fe3O4@CdS NHs was monitored for the degradation of xylenol orange dye. Compared with CdS and Fe3O4, as‐synthesized Fe3O4@CdS displayed superior performances in the photodegradation of xylenol orange. Possible mechanisms involved in the degradation of xylenol orange are also discussed.

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“…Temperature variation is one of the major affecting parameters in the growth of zinc salt nanoparticles which was not considered in details in [22]. Synthesis and characterization of differently structured CdS/ZnS sandwich and core-shell nanocomposites was recently investigated in [23]. A simple and modified chemical precipitation method under ambient conditions was used for the fabrication of those nanocomposites.…”

Section: Background Of the Previous Workmentioning

confidence: 99%

A Novel Thermochemical Method for Fabrication and Theoretical Explanation of High Luminescent Mn-Doped CdS Nanoparticles

Darvishi¹,

Nikfarjam²

2018

MSCE

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In this paper, fabrication and characterization of bare and doped CdS nanoparticles as well as investigating the luminescence properties of these particles as an important II-VI semiconductor are presented. A novel Thermochemical method was used for synthesis of these quantum dots. Thiols were used as the capping agent to prevent further growth during fabrication process. The application of TGA as a capping agent instead of TG was studied as a novel idea in this paper and was used practically in the synthesis of semiconductor nanoparticles. Using this process resulted in particles with sizes between 3 -7 nm. Several samples were synthesized and characterized under various Mn ions doping ratio from 1:10 to 1:180, different temperatures from 40˚C to 96˚C and different pH values from 6 to 10. Synthesis of CdS nanoparticles with high Mn ions concentration resulted in luminescence decrement, while luminescence of nanoparticles was increased by decreasing Mn/Cd doping ratio until Mn:Cd = 1:180. The best fabrication temperature was obtained at 96˚C and the highest luminescence was observed at the pH value of 9. A theoretical explanation for the behavior of fabricated high luminescent quantum dots is presented based on the principles of quantum mechanics. Among semiconductor nano-materials, CdS nanoparticles have attracted considerable attention due to their unique properties, which do not present in their bulk materials [2]. These unique properties introduce them as the important and useful materials for various applications such as solar cells, photodetectors, light-emitting diodes, photoelectrolysis and biological labels [3] [4] [5] [6].Nanoparticles have been grown in a variety of ways, namely precipitation in the solid phase [7] [8], using porous materials as templates [9], growth in nano-sized micelles and precipitation in the liquid phase [10] [11].

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Synthesis, characterization and visible-light driven photocatalysis by differently structured CdS/ZnS sandwich and core–shell nanocomposites

Cited by 46 publications

References 48 publications

Excitons with Reverse Rectifying Characteristics for Superior Solar Photocatalysis

Excitons with Reverse Rectifying Characteristics for Superior Solar Photocatalysis

Magnetically Separable Fe₃O₄@CdS Type‐II Nanohybrids with Excellent Photocatalytic Activity and Antibacterial Properties

A Novel Thermochemical Method for Fabrication and Theoretical Explanation of High Luminescent Mn-Doped CdS Nanoparticles

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Synthesis, characterization and visible-light driven photocatalysis by differently structured CdS/ZnS sandwich and core–shell nanocomposites

Cited by 46 publications

References 48 publications

Excitons with Reverse Rectifying Characteristics for Superior Solar Photocatalysis

Excitons with Reverse Rectifying Characteristics for Superior Solar Photocatalysis

Magnetically Separable Fe3O4@CdS Type‐II Nanohybrids with Excellent Photocatalytic Activity and Antibacterial Properties

A Novel Thermochemical Method for Fabrication and Theoretical Explanation of High Luminescent Mn-Doped CdS Nanoparticles

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Magnetically Separable Fe₃O₄@CdS Type‐II Nanohybrids with Excellent Photocatalytic Activity and Antibacterial Properties