scholarly journals The Effect of AgInS2, SnS, CuS2, Bi2S3 Quantum Dots on the Surface Properties and Photocatalytic Activity of QDs-Sensitized TiO2 Composite

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 403 ◽  
Author(s):  
Anna Malankowska ◽  
Daria Kulesza ◽  
Jakub Sowik ◽  
Onur Cavdar ◽  
Tomasz Klimczuk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Photocatalytic Activity ◽  
Surface Properties ◽  
Toluene Degradation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Hot Injection

The effect of type (AgInS2, SnS, CuS2, Bi2S3) and amount (5, 10, 15 wt%) of quantum dots (QDs) on the surface properties and photocatalytic activity of QDs-sensitized TiO2 composite, was investigated. AgInS2, SnS, CuS2, Bi2S3 QDs were obtained by hot-injection, sonochemical, microwave, and hot-injection method, respectively. To characterize of as-prepared samples high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Vis spectroscopy and photoluminescence (PL) emission spectroscopy were applied. The size of AgInS2, SnS, CuS2, Bi2S3 QDs were 12; 2–6; 2–3, and 1–2 nm, respectively. The QDs and QDs-sensitized TiO2 composites obtained have been tested in toluene degradation under LEDs light irradiation (λmax = 415 nm and λmax = 375 nm). For pristine QDs the efficiency of toluene degradation increased in the order of AgInS2 < Bi2S3 < CuS < SnS under 375 nm and AgInS2 < CuS < Bi2S3 < SnS under 415 nm. In the presence of TiO2/SnS QDs_15% composite, 91% of toluene was degraded after 1 h of irradiation, and this efficiency was about 12 higher than that for pristine QDs under 375 nm. Generally, building the TiO2/AgInS2 and TiO2/SnS exhibited higher photoactivity under 375 nm than the pristine TiO2 and QDs which suggests a synergistic effect between QDs and TiO2 matrix.

Microstructure characteristics of non-monodisperse quantum dots: on the potential of transmission electron microscopy combined with X-ray diffraction

CrystEngComm ◽  
2020 ◽  
Vol 22 (21) ◽  
pp. 3644-3655
Author(s):  
Stefan Neumann ◽  
Christina Menter ◽  
Ahmed Salaheldin Mahmoud ◽  
Doris Segets ◽  
David Rafaja
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Cdse Quantum Dots ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructure Characteristics ◽  
Scale Bridging ◽  
Transmission Electron ◽  
Hot Injection

Capability of TEM and XRD to reveal scale-bridging information about the microstructure of non-monodisperse quantum dots is illustrated on the CdSe quantum dots synthesized using an automated hot-injection method.

scholarly journals Síntesis de Puntos Cuánticos de SnO2 por Precipitación Química Asistida con Radiación Ultrasónica

2018 ◽  
pp. 97-101
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Crystallite Size ◽  
Chemical Precipitation ◽  
Ultrasonic Waves ◽  
X Ray Diffraction ◽  
Rutile Structure ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy

Síntesis de Puntos Cuánticos de SnO2 por Precipitación Química Asistida con Radiación Ultrasónica P. Alvarado1, D. Acosta2, M.M. Gomez1, J.L. Solis1,2 1 Facultad de Ciencias, Universidad Nacional de Ingeniería, Lima 25, Perú 2 Laboratorio de Películas Delgadas, Instituto de Física, UNAM, Circuito de la Investigación Científica, Ciudad Universitaria, C.P. 04510, México Recibido 8 de noviembre del 2018, Revisado el 10 de diciembre de 2018. Aceptado el 12 de diciembre de 2018 DOI: https://doi.org/10.33017/RevECIPeru2018.0015/ Resumen Puntos cuánticos de SnO2 fueron preparados vía precipitación química asistida con ondas ultrasonicas. Análisis de difracción de rayos (XRD) confirmaron la estructura tetragonal tipo rutilo de los puntos cuánticos de SnO2 con tamaño de cristalito de 1,4 nm. Las micrografías de microscopia electrónica de barrido (SEM) de la muestra en polvo obtenida muestra que los puntos cuánticos de SnO2 son partículas aglomeradas alrededor de 10 nm, mientras las imágenes de microscopia electrónica de transmisión (TEM) confirman que el tamaño del cristalito es similar a la medición realizada por difracción de rayos X (XRD). El ancho de banda de energía de los puntos cuánticos de SnO2 medida por espectroscopia UV Vis de reflexión difusa fue de 4.3 eV, mostrando un significativo desplazamiento atribuido al confinamiento cuántico. Descriptores: Puntos cuánticos, ultrasónicos. Abstract SnO2 quantum dots were prepared via chemical precipitation assisted with ultrasonic waves. X-ray diffraction analysis (XRD) confirmed the tetragonal rutile structure of quantum dots SnO2 with crystallite size of 1.4 nm. The scanning electron microscopy (SEM) micrographs of the obtained powder sample show that the SnO2 quantum dots are agglomerated particles around 10 nm, while the transmission electron microscopy (TEM) images confirm that the crystallite size is similar to the measurement made by X-ray diffraction (XRD). The energy bandwidth of the quantum dots of SnO2 measured by UV Vis spectroscopy of diffuse reflection was 4.3 eV, showing a significant displacement attributed to the quantum confinement. Keywords: Quantum points, ultrasonic.

Few-Layered MoS2 Nanostructures for Highly Efficient Visible Light Photocatalysis

NANO ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. 1650114 ◽  
Author(s):  
Dan Li ◽  
Jianwei Li ◽  
Caiqin Han ◽  
Xinsheng Zhao ◽  
Haipeng Chu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
Electrochemical Impedance Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Hole Pair

Few-layered MoS2 nanostructures were successfully synthesized by a simple hydrothermal method without the addition of any catalysts or surfactants. Their morphology, structure and photocatalytic activity were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, electrochemical impedance spectra and UV-Vis absorption spectroscopy, respectively. These results show that the MoS2 nanostructures synthesized at 180[Formula: see text]C exhibit an optimal visible light photocatalytic activity (99%) in the degradation of Rhodamine B owing to the relatively easier adsorption of pollutants, higher visible light absorption and lower electron–hole pair recombination.

scholarly journals Microwave-assisted preparation of ZnS and ZnSe nanocrystals with different morphologies for photodegradation process of organic dyes

2019 ◽  
Author(s):  
Katarzyna Matras-Postolek ◽  
A. Zaba ◽  
S. Sovinska ◽  
D. Bogdal
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Organic Dyes ◽  
Zinc Sulphide ◽  
Conventional Heating ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy

Zinc sulphide (ZnS) and zinc selenide (ZnSe) and manganese-doped and un-doped with different morphologies from 1D do 3D microflowers were successfully fabricated in only a few minutes by solvothermal reactions under microwave irradiation. In order to compare the effect of microwave heating on the properties of obtained  nanocrystals, additionally the synthesis under conventional heating was conducted additionally in similar conditions. The obtained nanocrystals were systematically characterized in terms of structural and optical properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-Vis spectroscopy (DR UV-Vis), Fourier-transform infrared spectroscopy (FT-IR), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area analysis. The photocatalytic activity of ZnSe, ZnS, ZnS:Mn and ZnSe:Mn nanocrystals with different morphologies was evaluated by the degradation of methyl orange (MO) and Rhodamine 6G (R6G), respectively. The results show that Mn doped NCs samples had higher coefficient of degradation of organic dyes under ultraviolet irradiation (UV).

Optical properties and energy transfer processes in Tb3+-doped ZnSe quantum dots

2021 ◽  
Author(s):  
Nguyen Ca ◽  
N. D Vinh ◽  
Phan Van Do ◽  
N. T. Hien ◽  
Xuan Hoa Vu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Chemical Method ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Transfer Processes ◽  
Transmission Electron ◽  
Wet Chemical

Tb3+-doped ZnSe quantum dots (QDs) with Tb content in the range of 0.5 - 7% were successfully synthesized by a wet chemical method. X-ray diffraction (XRD) and transmission electron microscopy...

scholarly journals Formation of ZnO/Zn0.5Cd0.5Se Alloy Quantum Dots in the Presence of High Oleylamine Contents

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 999
Author(s):  
Yi-An Chen ◽  
Kuo-Hsien Chou ◽  
Yi-Yang Kuo ◽  
Cheng-Ye Wu ◽  
Po-Wen Hsiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Particle Size ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Average Size ◽  
Alloy Quantum Dots ◽  
First Time

To the best of our knowledge, this report presents, for the first time, the schematic of the possible chemical reaction for a one-pot synthesis of Zn0.5Cd0.5Se alloy quantum dots (QDs) in the presence of low/high oleylamine (OLA) contents. For high OLA contents, high-resolution transmission electron microscopy (HRTEM) results showed that the average size of Zn0.5Cd0.5Se increases significantly from 4 to 9 nm with an increasing OLA content from 4 to 10 mL. First, [Zn(OAc)2]–OLA complex can be formed by a reaction between Zn(OAc)2 and OLA. Then, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) data confirmed that ZnO is formed by thermal decomposition of the [Zn(OAc)2]–OLA complex. The results indicated that ZnO grew on the Zn0.5Cd0.5Se surface, thus increasing the particle size. For low OLA contents, HRTEM images were used to estimate the average sizes of the Zn0.5Cd0.5Se alloy QDs, which were approximately 8, 6, and 4 nm with OLA loadings of 0, 2, and 4 mL, respectively. We found that Zn(OAc)2 and OLA could form a [Zn(OAc)2]–OLA complex, which inhibited the growth of the Zn0.5Cd0.5Se alloy QDs, due to the decreasing reaction between Zn(oleic acid)2 and Se2−, which led to a decrease in particle size.

Facile synthesis of water-soluble graphene-based composite: Non-covalently functionalized with chitosan-ionic liquid conjugation

2016 ◽  
Vol 09 (03) ◽  
pp. 1650045 ◽  
Author(s):  
Pei-Ying Li ◽  
Kai-Yu Cheng ◽  
Xiu-Cheng Zheng ◽  
Pu Liu ◽  
Xiu-Juan Xu
Keyword(s):  
Electron Microscopy ◽  
Ionic Liquid ◽  
Chemical Reduction ◽  
Water Soluble ◽  
X Ray Diffraction ◽  
Facile Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Text Interaction

Chitosan-ionic liquid conjugation (CILC), which was prepared through the reaction of 1-(4-bromobutyl)-3-methylimidazolium bromide (BBMIB) with chitosan, was firstly used to prepare functionalized graphene composite via the chemical reduction of graphene oxide (GO). The obtained water soluble graphene-based composite was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), ultraviolet-visible (UV–Vis) spectroscopy and so on. CILC-RGO showed excellent dispersion stability in water at the concentration of 2.0 mg/mL, which was stable for several months without any precipitate. This may be ascribed to the electrostatic attraction and [Formula: see text]–[Formula: see text] interaction between CILC and graphene.

scholarly journals Hydrothermal synthesis of ZnO quantum dot/KNb3O8 nanosheet photocatalysts for reducing carbon dioxide to methanol

2017 ◽  
Vol 8 ◽  
pp. 2264-2270 ◽  
Author(s):  
Xiao Shao ◽  
Weiyue Xin ◽  
Xiaohong Yin
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Uv Light ◽  
Formation Rate ◽  
X Ray Diffraction ◽  
Methanol Production ◽  
X Ray ◽  
Transmission Electron ◽  
Methanol Formation ◽  
Zno Quantum Dots

ZnO quantum dots and KNb3O8 nanosheets were synthesized by a two-step hydrothermal method for the photocatalytic reduction of CO2 to methanol where isopropanol is simultaneously oxidized to acetone . The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and UV–vis absorption spectroscopy (UV–vis). The photocatalytic activity of the materials was evaluated by formation rate of methanol under UV light irradiation at ambient temperature and pressure. The methanol formation rate of pure KNb3O8 nanosheets was found to be 1257.21 μmol/g/h, and after deposition of 2 wt % ZnO quantum dots on the surface of KNb3O8 nanosheets, the methanol production rate was found to increase to 1539.77 μmol/g/h. Thus, the ZnO quantum dots obviously prompted separation of charge carriers, which was explained by a proposed mechanism for this photocatalytic reaction.

Hydrothermal Synthesis and Photocatalytic Properties of Flower-Like CdS Nanostructures

2011 ◽  
Vol 335-336 ◽  
pp. 460-463 ◽  
Author(s):  
Hong Mei Wang ◽  
Da Peng Zhou ◽  
Yuan Lian ◽  
Ming Pang ◽  
Dan Liu
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Sulfur Source ◽  
X Ray Diffraction ◽  
Facile Hydrothermal Method ◽  
X Ray ◽  
Transmission Electron ◽  
Cds Nanostructures

Hexagonal flower-like CdS nanostructures were successfully synthesized through a facile hydrothermal method with thiourea as sulfur source. By combining the results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), the structural and morphological characterizations of the products were performed. The photocatalytic activity of CdS nanostructures had been tested by degradation of Rhodamine B (RB) under UV light compared to commercial CdS powders, which indicated that the as-syntherized CdS nanostructures exhibited enhanced photocatalytic activity for degradation of RB. The possible growth mechanism of CdS nanostructures was proposed in the end.

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