Facile preparation of ZnO particles with different structures and their photocatalytic activity

2016 ◽  
Vol 13 (5) ◽  
pp. 394-398
Author(s):  
Li Bian ◽  
Meixia Li ◽  
Yiwei Lian ◽  
Yongjing Hao ◽  
Juan Xie
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Organic Pollutant ◽  
Diffraction Field ◽  
Structure Directing Agent ◽  
Simple Method ◽  
Content Type ◽  
Zno Particles ◽  
Solution Route

Purpose This paper aims to report a novel preparation method of ZnO particles with different structures and their photocatalytic activity. Design/methodology/approach ZnO powders are prepared by a facile, economical and environment-friendly aqueous solution route. X-ray diffraction, field emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy and UV-vis diffuse reflectance spectra are used to characterize the products. Photocatalytic activity of the samples is evaluated by degradation of organic pollutant pentachlorophenol under UV-vis irradiation. Findings It is found that three-dimensional ZnO hierarchical structures can be prepared via aqueous solution route without using any template or structure-directing agent, and the alkalinity of reaction solution is the key factor. All the as-prepared ZnO products have good catalytic activity under UV-vis light irradiation. Originality/value This report presents a simple method for the preparation of ZnO particles with excellent photocatalytic activity. Experimental results could provide useful reference for the treatment of chlorophenols in the future.

scholarly journals Enhanced Photocatalytic Activity of Hybrid rGO@TiO2/CN Nanocomposite for Organic Pollutant Degradation under Solar Light Irradiation

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1023
Author(s):  
Martina Kocijan ◽  
Lidija Ćurković ◽  
Tina Radošević ◽  
Matejka Podlogar
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Tio2 Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Ph Value ◽  
Organic Pollutant ◽  
Anatase Tio2 ◽  
X Ray

The three-component hybrid (rGO/TiO2/CN) nanocomposite was prepared in order to enhance the photocatalytic properties of anatase TiO2 nanoparticles (NPs) under solar-like irradiation. The rGO/TiO2/CN was prepared in a mixture of the reduced graphene oxide (rGO, 8 wt%), anatase TiO2 nanoparticles (NPs), and graphitic carbon nitride (g-C3N4, 16 wt%). It was self-assembled through the one-step hydrothermal method, followed by an annealing process. The photocatalyst was thoroughly characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunauer-Emmett-Teller (BET) nitrogen adsorption/desorption technique and UV-Vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the TiO2, TiO2/rGO, TiO2/CN and hybrid rGO/TiO2/CN nanocomposite was studied through the degradation of a rhodamine B (RhB) aqueous solution under solar-like irradiation. The results showed that the highest photocatalytic activity was achieved by the rGO/TiO2/CN mixture, which can be attributed to the synergistic effect of the incorporation of both rGO and g-C3N4 with TiO2. Further, the influence of the pH value of the RhB dye aqueous solution and different water matrix (Milli-Q, tap, and alkaline water) on the photocatalytic efficiency of the rGO/TiO2/CN nanocomposite was examined. In addition, a recycle test was performed for hybrid rGO@TiO2/CN to investigate the effectiveness of the photodegradation of RhB dye in three successive cycles. The conducted results indicate that the pH value of RhB dye aqueous solution and water matrices play an important role in the photocatalytic degradation rate.

scholarly journals Synthesis of TiO2/Pd and TiO2/PdO Hollow Spheres and Their Visible Light Photocatalytic Activity

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Jing Yan ◽  
Xiaojuan Li ◽  
Bo Jin ◽  
Min Zeng ◽  
Rufang Peng
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Hollow Spheres ◽  
Active Species ◽  
Degradation Efficiency ◽  
Diffraction Field ◽  
Transmission Electron

A series of TiO2, TiO2/Pd, and TiO2/PdO hollow sphere photocatalysts was successfully prepared via a combination of hydrothermal, sol-immobilization, and calcination methods. The structure and optical properties of the as-prepared samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Telleranalysis, Barrett-Joyner-Halenda measurement, and UV-Vis diffuse reflectance spectroscopy. The photocatalysis efficiencies of all samples were evaluated through the photocatalytic degradation of rhodamine B under visible light irradiation. Results indicated that TiO2/PdO demonstrated a higher photocatalytic activity (the photocatalytic degradation efficiency could reach up to 100% within 40 min) than the other samples and could maintain a stable photocatalytic degradation efficiency for at least four cycles. Finally, after using different scavengers, superoxide and hydroxyl radicals were identified as the primary active species for the effectiveness of the TiO2/PdO photocatalyst.

Synthesis and Recycle of ZnO Particles for Degradation of Methyl Orange Aqueous Solution

2011 ◽  
Vol 121-126 ◽  
pp. 587-591 ◽  
Author(s):  
Li Qin Wang ◽  
Xiang Ni Yang ◽  
Xiu Li Zhao ◽  
Yang Han ◽  
Rui Jun Zhang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Lamellar Structure ◽  
Degradation Rate ◽  
Mesoporous Structure ◽  
High Photocatalytic Activity ◽  
Type Iv ◽  
Zno Particles ◽  
Adsorption Desorption

The ZnO particles with mesoporous and lamellar structure were synthesized in the method of precipitation, using zinc acetate as precursor. The ZnO particles were characterized by the means of scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and N2 adsorption–desorption measurements. The photoactivity of as-prepared ZnO particles was evaluated by degradation experiment of methyl orange aqueous solution. The results showed the obtained ZnO particles were irregular polygons with lamellar structure, and the particle size was in the range of 50 nm to 300 nm. According to XRD and N2 absorption results, ZnO particles were pure and integrated crystals with high crystallinity, and adsorption-desorption isotherms correspond to the typical type IV isotherm with a hysteresis loop of type H3, which showed ZnO particles had mesoporous structure with slit pore shape. The ZnO particles had high photocatalytic activity, the maximum degradation rate of methyl orange aqueous solution can reach 99%. When reused for the fifth time, the photocatalytic activity of ZnO particles was similar with the fresh ones, and recycled for the tenth time, the degradation rate of methyl orange aqueous solution still standed by 84.7%.

scholarly journals Electrospinning Synthesis and Photocatalytic Activity of Mesoporous TiO2Nanofibers

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Jing Li ◽  
Hui Qiao ◽  
Yuanzhi Du ◽  
Chen Chen ◽  
Xiaolin Li ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
High Photocatalytic Activity ◽  
Electrospinning Technique ◽  
Obvious Effect ◽  
Simple Method ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Excellent Photocatalytic Activity

Titanium dioxide (TiO2) nanofibers in the anatase structure were successfully prepared via electrospinning technique followed by calcination process. The morphologies, crystal structure, surface area, and the photocatalytic activity of resulting TiO2nanofibers were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen sorption, and UV-vis spectroscopy. The results revealed that calcination temperature had greatly influenced the morphologies of TiO2nanofibers, but no obvious effect was noticed on the crystal structure of TiO2nanofibers. The photocatalytic properties of TiO2nanofibers were evaluated by photocatalytic degradation of rhodamine B (RhB) in water under visible light irradiation. It was observed that TiO2nanofibers obtained by calcination at 500°C for 3 hours exhibited the most excellent photocatalytic activity. We present a novel and simple method to fabricate TiO2nanofibers with high-photocatalytic activity.

scholarly journals Enhancement of Visible-Light Photocatalytic Activity of Mesoporous Au-TiO2Nanocomposites by Surface Plasmon Resonance

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Minghua Zhou ◽  
Jun Zhang ◽  
Bei Cheng ◽  
Huogen Yu
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Surface Plasmon Resonance ◽  
Visible Light ◽  
Hydroxyl Radicals ◽  
Rhodamine B ◽  
Au Nanoparticles ◽  
Photocatalytic Decolorization ◽  
Visible Light Photocatalytic

Mesoporous Au-TiO2nanocomposite plasmonic photocatalyst with visible-light photoactivity was prepared by a simple spray hydrolytic method using photoreduction technique at90∘C. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2adsorption-desorption isotherms. The formation of hydroxyl radicals (•OH) on the surface of visible-light illuminated Au-TiO2nanocomposites was detected by the luminescence technique using terephthalic acid as probe molecules. The photocatalytic activity was evaluated by photocatalytic decolorization of Rhodamine-B (RhB) aqueous solution under visible-light irradiation (λ >  420 nm). The results revealed that the TiO2could be crystallizedviaspray hydrolysis method, and the photoreduction technique was facilitated to prepare Au nanoparticles in the mesoporous TiO2at90∘C. The light absorption, the formation rate of hydroxyl radicals, and photocatalytic decolorization of Rhodamine-B aqueous solution were significantly enhanced by those embedded Au nanoparticles in the Au-TiO2nanocomposites. The prepared Au-TiO2nanocomposites exhibit a highly visible-light photocatalytic activity for photocatalytic degradation of RhB in water, and their photocatalytic activity is higher than that of the pristine TiO2nanoparticles due to the surface plasmon resonance.

Preparation of Nano-Co3O4 by Direct Thermal Decomposition of Cobalt(II) Nitrate Hexahydrate for Electrochemical Water Oxidation

2018 ◽  
Vol 14 (2) ◽  
pp. 154-159 ◽  
Author(s):  
Mohammed Ameen Ahmed Qasem ◽  
Md. Abdul Aziz ◽  
Abbas Saeed Hakeem ◽  
Sagheer A. Onaizi
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Filter Paper ◽  
Water Oxidation ◽  
Diffraction Field ◽  
Nitrate Hexahydrate ◽  
Carbon Electrode ◽  
Simple Method ◽  
Normal Filter ◽  
Electrocatalytic Properties

Background: Nano-Co3O4 has been used in various technological areas and applications such as electrochemical sensors and electrochemical water splitting. Even though many efforts have been expended to prepare nano-Co3O4, the development of novel methods to prepare Co3O4 using simple processes and at low cost remain a topic of interest. Besides, it could be economic and useful if the synthesized nanoparticle could be applied as efficient electrocatalyst upon its immobilization on a cheap base electrode material by very simple method for various practical applications including renewable energy. Method: We prepared nano-Co3O4 by a direct thermal decomposition of an inexpensive, simple and widely available cobalt inorganic precursor, such as Co(NO3)2·6H2O without any type of prereaction or processing. The nano-Co3O4 was immobilized on filter-paper-derived carbon electrode by drop-drying method for applying as electrode materials toward water electrooxidation. Results: The X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy analysis confirmed the formation of short nanorods of single-phase Co3O4 upon thermal decomposition of Co(NO3)2·6H2O at 520°C. The electrocatalytic properties of the nano- Co3O4 were evaluated after immobilizing it on a cheap carbon electrode derived from normal filter paper. The modified electrode showed good electrocatalytic properties toward water oxidation in an alkaline solution. Conclusion: In conclusion, we developed a very simple, straight-forward and economic method for preparation of nano-Co3O4 and immobilized it on very cheap carbon electrode for evaluating its electrocatalytic properties. Due to the high electrocatalytic properties, the prepared nano-Co3O4 could potentially play an important role in various practical fields.

Enhancement of PMS activation in an UV/ozone process for cyanide degradation: a comprehensive study

2020 ◽  
Vol 49 (5) ◽  
pp. 409-414
Author(s):  
Zahra Goodarzvand Chegini ◽  
Hessam Hassani ◽  
Ali Torabian ◽  
Seyed Mehdi Borghei
Keyword(s):  
Aqueous Solution ◽  
Complete Removal ◽  
The Novel ◽  
Simple Method ◽  
Content Type ◽  
Cyanide Degradation ◽  
Catalytic Role ◽  
Nitrite Nitrate ◽  
Optimized Conditions ◽  
Uv Ozone

Purpose This paper aims to study peroxymonosulfate (PMS) activation in the ultraviolet (UV)/ozone process for toxic cyanide degradation from aqueous solution by a novel and simple method. Design/methodology/approach Photocatalytic degradation of cyanide (CN-) was carried out using a bench-scale photoreactor. Optimization of the UV/ozone process for the highest removal of cyanide was obtained. The effect of parameters such as ozone concentration, PMS concentration, temperature, cations (Cu2+, Co2+ and Fe2+), cyanide concentration, anions (bicarbonate, carbonate, chloride, nitrite, nitrate and sulfate [SO42−]) and scavengers (ethanol [EtOH], humic acid, TBA and NaN3) was investigated for CN- degradation. Findings Complete removal of 50 mg/L cyanide was obtained in 4 min in an ozone/UV/PMS process. The cyanide removal increased from 49.3% to 100% by adding the persulfate dosage up to 100 mg/L. The effect of various cations (II) on the cyanide degradation was enhanced in the order Cu2+ > Co2+ > Fe2+. Hydroxyl radical based on different radical quenchers such as salicylic acid proved as the main oxidizing radical for oxidation. The application of ozone/UV/PMS to treat wastewater containing cyanide shows high degradation efficiency. Research limitations/implications The ozone/UV/PMS system could be a process for degradation and detoxification of cyanide. Practical implications This study provided a simple and effective method for degradation of cyanide from aqueous solution. This method was applicable to protect environment from a huge amount of toxic cyanide wastewater produced by different industrial processes. Originality/value The PMS activation is done via a simple and effective method, which is carried out with the ozone/UV system. There are two main innovations. One is that the novel catalytic role of bimetallic ions in the ozone reaction with cyanide and the further decomposition of intermediate products is investigated. The other is that the optimized conditions were obtained for the removal of cyanide as a water contaminant. Furthermore, predominant oxidizing species by PMS activation are identified.

A simple method to prepare carbon nanotubes from sunflower seed hulls and sago and their application in supercapacitor

2015 ◽  
Vol 44 (1) ◽  
pp. 7-12 ◽  
Author(s):  
H.Y. Zhang ◽  
H.J. Niu ◽  
Y.M. Wang ◽  
C. Wang ◽  
X.D. Bai, ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Sunflower Seed ◽  
Electrochemical Impedance ◽  
Cyclic Voltammograms ◽  
Production Scale ◽  
Simple Method ◽  
Content Type ◽  
X Ray

Purpose – The purpose of this paper was to provide a simple method for the preparation of carbon nanotubes (CNTs) by pyrolysing sunflower seed hulls and sago and to evaluate the application of such CNTs in supercapacitors. Design/methodology/approach – The CNTs were obtained by pyrolysing sunflower seed hulls and sago at 800°C. The prepared CNTs were studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, cyclic voltammograms, galvanostatic charge and discharge and electrochemical impedance spectra methods. Findings – The CNTs had large surface areas as determined by the methylene blue method and the Brunauer – Emmett – Teller method. And the CNTs that were prepared by pyrolysing the natural sunflower seed hulls (denoted as CNTs-1) and sago (denoted as CNTs-2) had capacitances of 86.9 F/g and 26.7 F/g, respectively. Research limitations/implications – The capacitances of CNTs can be further improved. Practical implications – The exceptional electronic and mechanical properties of CNTs prepared lend the CNTs to diverse applications including electrocatalysts, hydrogen storage, photovoltaic devices actuators, energy storage, field-emitting flat panel displays and composites. Originality/value – Currently, CNTs have not yet been used in the industry at a mass production scale due to high costs associated. The outcomes of the study reported in this article could provide a convenient method in aid of industrialisation of the production of CNTs.

scholarly journals Enhancement of Photocatalytic Activity on TiO2-Nitrogen-Doped Carbon Nanotubes Nanocomposites

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Lingling Wang ◽  
Long Shen ◽  
Yihuai Li ◽  
Luping Zhu ◽  
Jiaowen Shen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Photocatalytic Activity ◽  
Organic Pollutant ◽  
Scanning Calorimetry ◽  
Nitrogen Doped ◽  
Photogenerated Electrons ◽  
Transmission Electron ◽  
Effective Transfer ◽  
Nitrogen Doped Carbon

TiO2-nitrogen-doped carbon nanotubes (TiO2-CNx) nanocomposites are successfully synthesized via a facile hydrothermal method. The prepared photocatalysts were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric and differential scanning calorimetry analyses (TGA-DSC). The results show that the TiO2nanoparticles with a narrow size of 7 nm are uniformly deposited on CNx. The photocatalytic activity of the nanocomposite was studied using methyl orange (MO) as a model organic pollutant. The experimental results revealed that the strong linkage between the CNx and TiO2played a significant role in improving photocatalytic activity. However, the mechanical process for CNx and TiO2mixtures showed lower activity than neat TiO2. Moreover, TiO2-CNx nanocomposites exhibit much higher photocatalytic activity than that of neat TiO2and TiO2-CNTs nanocomposites. The improved photodegradation performances are attributed to the suppressed recombination of electrons and holes caused by the effective transfer of photogenerated electrons from TiO2to CNx.

scholarly journals Магнитные нанокомпозиты MgFe-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=-/SiO-=SUB=-2-=/SUB=- типа ядро/оболочка для биомедицинских применений: синтез и свойства

2018 ◽  
Vol 60 (9) ◽  
pp. 1707
Author(s):  
А.С. Камзин ◽  
H. Das ◽  
N. Wakiya ◽  
А.А. Валиуллин
Keyword(s):  
Electron Microscopy ◽  
Silicon Dioxide ◽  
Spherical Particles ◽  
Diffraction Field ◽  
Core Shell ◽  
Total Size ◽  
Simple Method ◽  
Transmission Electron ◽  
Biological Compatibility ◽  
Field Emission Electron Microscopy

AbstractMagnetic core/shell (CS) nanocomposites (MNCs) are synthesized using a simple method, in which a magnesium ferrite nanoparticle (MgFe_2O_4) is a core, and an amorphous silicon dioxide (silica SiO_2) layer is a shell. The composition, morphology, and structure of synthesized particles are studied using X-ray diffraction, field emission electron microscopy, transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), scattering electrophoretic photometer, thermogravimetric analysis (TGA), and Mössbauer spectroscopy. It is found that the MgFe_2O_4/SiO_2 MNC has the core/shell structure formed by the Fe‒O–Si chemical bond. After coating with silica, the MgFe_2O_4/SiO_2 MNC saturation magnetization significantly decreases in comparison with MgFe_2O_4 particles without a SiO_2 shell. Spherical particles agglomerated from MgFe_2O_4 nanocrystallites ∼9.6 and ∼11.5 nm in size function as cores coated with SiO_2 shells ∼30 and ∼50 nm thick, respectively. The total size of obtained CS MNCs is ∼200 and 300 nm, respectively. Synthesized CS MgFe_2O_4/SiO_2 MNCs are very promising for biomedical applications, due to the biological compatibility of silicon dioxide, its sizes, and the fact that the Curie temperature is in the region required for hyperthermal therapy, 320 K.

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