Anatomy of a Natural Sunlight Driven CdS/CoTiO3/ZnO Ternary Photocatalyst for Efficient Optical Properties and Removal of Reactive Orange 30

2021 ◽  
Vol 25 (8) ◽  
pp. 100-109
Author(s):  
G. Divya ◽  
D. Sakthi ◽  
A. Priyadharsan ◽  
S. Boobas ◽  
S. Sivakumar

ZnO as a promising photocatalyst has gained much attention for the removal of organic pollutants from water. However, the main drawbacks of the relatively low photocatalytic activity and high recombination rate of photoexcited electron-hole pairs restrict its potential applications. Promoting the spatial separation of photoexcited charge carriers is of paramount significance for photocatalysis because the difference in the band positions makes the potential gradient at the composite boundary. In this work, binary CdS/ZnO and CoTiO3/ZnO are first prepared by dispersion method and then decorated with ZnO particles to construct CdS/CoTiO3/ZnO ternary composites. For this reason, the CdS/CoTiO3/ZnO ternary composites was effectively designed and analyzed for the crystalline structure, light absorption, photoexcitation behavior and surface morphological properties by X-ray diffraction, diffuse reflectance UV/visible absorption spectroscopy, photoluminescence spectroscopy and scanning electron micrograph respectively. The photocatalytic activity was examined by degradation of the dye solution spectrophotometrically. The results of photocatalytic degradation indicated that the CdS/CoTiO3/ZnO ternary composites are much higher than those of bare CdS, CoTiO3, ZnO and any binary composites such as CoTiO3/ZnO and ZnO/CdS. The enhanced activity could be attributed to the drop electron transfer from CdS to ZnO to CoTiO3 through the interfacial potential gradient in the ternary hybrid conduction bands. The enhanced electron transfer of CdS/CoTiO3/ZnO ternary composites was also applicable to degrade other reactive dyes.

2021 ◽  
Author(s):  
B. Yalcin ◽  
S. Ozcelik ◽  
K. Icin ◽  
K. Senturk ◽  
B. Ozcelik ◽  
...  

Abstract The synthesis of magnetic nano-size spinel ferrites has become an important area of research, due to their several potential applications. In this work, CoFe2O4 nanoparticles were synthesized by the co-precipitation method. Structural, magnetic and photocatalytic properties of cobalt ferrites were analyzed based on their chemical composition considering their biological properties. Structural and morphological properties were investigated by X-ray diffraction analysis (XRD) and SEM respectively. Lattice parameters and cell volumes were calculated from XRD data. SEM images revealed uniform surface morphology and spherical shape of nanoparticles. Magnetization measurements were measured by using Lake Shore 7304 model Vibrating Sample Magnetometer. In hemolytic activity tests, formation of a precipitate with a characteristic black color provided an explicit evidence to the formation of heme-iron complexes. Undesirable hemolytic effect of CoFe2O4 nanoparticles on human erythrocytes at both concentrations was attributed to the comparatively high amount of reactive oxygen species formed by CoFe2O4 nanoparticles. The theoretical concentration Co (theory) obtained by second-order model (0.82 mg/L) fit with the experimental value of Co (experimental) (0.95 mg/L) well in photocatalytic activity tests.


2019 ◽  
Vol 8 (1) ◽  
pp. 56-61
Author(s):  
Aneeya K. Samantara ◽  
Debasrita Dash ◽  
Dipti L. Bhuyan ◽  
Namita Dalai ◽  
Bijayalaxmi Jena

: In this article, we explored the possibility of controlling the reactivity of ZnO nanostructures by modifying its surface with gold nanoparticles (Au NPs). By varying the concentration of Au with different wt% (x = 0.01, 0.05, 0.08, 1 and 2), we have synthesized a series of (ZnO/Aux) nanocomposites (NCs). A thorough investigation of the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface has been carried out. It was observed that ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity among all concentrations of Au on the ZnO surface, which degrades the dye concentration within 2 minutes of visible light exposure. It was further revealed that with an increase in the size of plasmonic nanoparticles beyond 0.08%, the accessible surface area of the Au nanoparticle decreases. The photon absorption capacity of Au nanoparticle decreases beyond 0.08% resulting in a decrease in electron transfer rate from Au to ZnO and a decrease of photocatalytic activity. Background: Due to the industrialization process, most of the toxic materials go into the water bodies, affecting the water and our ecological system. The conventional techniques to remove dyes are expensive and inefficient. Recently, heterogeneous semiconductor materials like TiO2 and ZnO have been regarded as potential candidates for the removal of dye from the water system. Objective: To investigate the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface and the effect of the size of Au NPs for photocatalytic performance in the degradation process. Methods: A facile microwave method has been adopted for the synthesis of ZnO nanostructure followed by a reduction of gold salt in the presence of ZnO nanostructure to form the composite. Results: ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity which degrades the dye concentration within 2 minutes of visible light exposure. The schematic mechanism of electron transfer rate was discussed. Conclusion: Raspberry shaped ZnO nanoparticles modified with different percentages of Au NPs showed good photocatalytic behavior in the degradation of dye molecules. The synergetic effect of unique morphology of ZnO and well anchored Au nanostructures plays a crucial role.


2021 ◽  
Author(s):  
Yan-Lei Lu ◽  
Wen-Long Lan ◽  
Wei Shi ◽  
Qionghua Jin ◽  
Peng Cheng

Photo-induced variation of magnetism from ligand-based electron transfer have been extensively studied because of their potential applications in magneto-optical memory devices, light-responsive switches, and high-density information storage materials. In this...


2020 ◽  
Vol 10 (1) ◽  
pp. 53-61
Author(s):  
E. Mysen

AbstractA network of pointwise available height anomalies, derived from levelling and GPS observations, can be densified by adjusting a gravimetric quasigeoid using least-squares collocation. The resulting type of Corrector Surface Model (CSM) is applied by Norwegian surveyors to convert ellipsoidal heights to normal heights expressed in the official height system NN2000. In this work, the uncertainty related to the use of a CSM to predict differences in height anomaly was sought. As previously, the application of variograms to determine the local statistical properties of the adopted collocation model led to predictions that were consistent with their computed uncertainties. For the purpose of predicting height anomaly differences, the effect of collocation was seen to be moderate in general for the small spatial separations considered (< 10 km). However, the relative impact of collocation could be appreciable, and increasing with distance, near the network. At last, it was argued that conservative uncertainties of height anomaly differences may be obtained by rescaling output of a grid interpolation by \sqrt \Delta, where Δ is the spatial separation of the two locations for which the difference is sought.


2016 ◽  
Vol 4 (38) ◽  
pp. 9027-9035 ◽  
Author(s):  
Daqin Chen ◽  
Weiwei Wu ◽  
Yongjun Yuan ◽  
Yang Zhou ◽  
Zhongyi Wan ◽  
...  

Nitrogen-doped carbon dots with multi-state visible absorption and full-color blue/yellow/red emissions are synthesized, and show potential applications in solid-state-lighting.


2021 ◽  
Author(s):  
L.F. Chen ◽  
U. Arellano ◽  
J.A. Wang ◽  
L.M. Balcázar ◽  
R. Sotelo ◽  
...  

Author(s):  
Yumeng Liang ◽  
Anfu Zhou ◽  
Huanhuan Zhang ◽  
Xinzhe Wen ◽  
Huadong Ma

Contact-less liquid identification via wireless sensing has diverse potential applications in our daily life, such as identifying alcohol content in liquids, distinguishing spoiled and fresh milk, and even detecting water contamination. Recent works have verified the feasibility of utilizing mmWave radar to perform coarse-grained material identification, e.g., discriminating liquid and carpet. However, they do not fully exploit the sensing limits of mmWave in terms of fine-grained material classification. In this paper, we propose FG-LiquID, an accurate and robust system for fine-grained liquid identification. To achieve the desired fine granularity, FG-LiquID first focuses on the small but informative region of the mmWave spectrum, so as to extract the most discriminative features of liquids. Then we design a novel neural network, which uncovers and leverages the hidden signal patterns across multiple antennas on mmWave sensors. In this way, FG-LiquID learns to calibrate signals and finally eliminate the adverse effect of location interference caused by minor displacement/rotation of the liquid container, which ensures robust identification towards daily usage scenarios. Extensive experimental results using a custom-build prototype demonstrate that FG-LiquID can accurately distinguish 30 different liquids with an average accuracy of 97%, under 5 different scenarios. More importantly, it can discriminate quite similar liquids, such as liquors with the difference of only 1% alcohol concentration by volume.


2017 ◽  
Vol 41 (4) ◽  
pp. 1723-1735 ◽  
Author(s):  
Lellala Kashinath ◽  
Keerthiraj Namratha ◽  
Shivanna Srikantaswamy ◽  
Ajayan Vinu ◽  
Kullaiah Byrappa

Excellent photocatalytic activity by highly photo-responsive electron transfer from ZnS–RGO, and RGO acts as an electron reservoir and effectively suppresses charge recombination.


2012 ◽  
Vol 509 ◽  
pp. 259-265
Author(s):  
Hao Xie ◽  
Tao Zeng ◽  
Xue Lai Wang ◽  
Xiu Jian Zhao

Three-dimensionally (3D) ordered macroporous ZnO film was fabricated on a glass slide by layer-by-layer depositing and hydrolysis of Zn(CH3COO)2using 3D-ordered latex film as template followed by calcination at 450 °C for 2 h to remove the organic template. The as-prepared 3D-ordered macroporous ZnO film was characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), diffusive reflectance UV-visible absorption spectra (DRUV-VIS), photoluminescence (PL), and photoelectrochemical measurement. Its photocatalytic activity was evaluated by the photocatalytic degradation of crystal violet (CV) aqueous solution at ambient temperature under the irradiation of simulated solar light. It was found that the 3D-ordered ZnO film exhibits efficient photocatalytic activity for photodegradation of CV under the irradiation of simulated solar light.


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