scholarly journals In-Situ Fabrication of g-C3N4/ZnO Nanocomposites for Photocatalytic Degradation of Methylene Blue: Synthesis Procedure Does Matter

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 215 ◽  
Author(s):  
Shengqiang Zhang ◽  
Changsheng Su ◽  
Hang Ren ◽  
Mengli Li ◽  
Longfeng Zhu ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Zinc Acetate ◽  
Diffuse Reflectance Spectroscopy ◽  
Low Cost ◽  
Zno Nanorods ◽  
Light Illumination ◽  
Maximum Reaction Rate ◽  
In Situ Fabrication

The nanocomposite preparation procedure plays an important role in achieving a well-established heterostructured junction, and hence, an optimized photocatalytic activity. In this study, a series of g-C3N4/ZnO nanocomposites were prepared through two distinct procedures of a low-cost, environmentally-friendly, in-situ fabrication process, with urea and zinc acetate being the only precursor materials. The physicochemical properties of synthesized g-C3N4/ZnO composites were mainly characterized by XRD, UV–VIS diffuse reflectance spectroscopy (DRS), N2 adsorption-desorption, FTIR, TEM, and SEM. These nanocomposites’ photocatalytic properties were evaluated in methylene blue (MB) dye photodecomposition under UV and sunlight irradiation. Interestingly, compared with ZnO nanorods, g-C3N4/ZnO nanocomposites (x:1, obtained from urea and ZnO nanorods) exhibited weak photocatalytic activity likely due to a “shading effect”, while nanocomposites (x:1 CN, made from g-C3N4 and zinc acetate) showed enhanced photocatalytic activity that can be ascribed to the effective establishment of heterojunctions. A kinetics study showed that a maximum reaction rate constant of 0.1862 min-1 can be achieved under solar light illumination, which is three times higher than that of bare ZnO nanorods. The photocatalytic mechanism was revealed by determining reactive species through adding a series of scavengers. It suggested that reactive ∙O2− and h+ radicals played a major role in promoting dye photodegradation.

scholarly journals Comparison of photocatalytic activity of ZnO, Ag-ZnO, Cu-ZnO, Ag, Cu-ZnO and TPPS/ZnO for the degradation of methylene blue under UV and visible light irradiation

2021 ◽  
Author(s):  
Mahboubeh Rabbani ◽  
Javad Shokrayian ◽  
Rahmatollah Rahimi ◽  
Rezvaneh Amrollahi
Keyword(s):  
Methylene Blue ◽  
Zinc Oxide ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Diffuse Reflectance Spectroscopy ◽  
Zno Nanorods ◽  
Light Irradiation ◽  
Zinc Oxide Nanorods ◽  
Ft Ir

Abstract In this study, Zinc Oxide and Silver and Copper-doped Zinc Oxide nanorods were synthesized by a simple template-free precipitation technique. In addition, meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS4) was prepared and immobilized on ZnO nanorods (TPPS/ZnO). The synthesized photocatalysts were characterized by various techniques such as X-Ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), UV-visible Spectroscopy, Diffuse Reflectance Spectroscopy (DRS), and Fourier Transform Infrared Spectroscopy (FT-IR). The potential of the obtained photocatalysts in the degradation of methylene blue was investigated under UV and visible light irradiation. The results revealed that the photocatalytic activity of TPPS/ZnO was higher than those of the pure ZnO and doped ZnO under visible light irradiation.

scholarly journals TiO2 NANOTUBES FOR PHOTOCATALYTIC DEGRADATION OF METHYLENE BLUE

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Vladimir Ciobanu ◽  
◽  
Irina Plesco ◽  
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Low Cost ◽  
Anatase Phase ◽  
Electrochemical Anodization ◽  
Outer Diameter ◽  
Light Illumination ◽  
Vis Spectroscopy

Titanium dioxide remains one of the most studied semiconductor for photocatalytic applications due to its low cost production, reduced toxicity, ability to break down the organic pollutants and possibility to achieve complete mineralization. In this work, we report on results of the photocatalytic activity of titanium dioxide nanotubes fabricated by electrochemical anodization technique in an electrolyte solution containing a mixture of hydrofluoric acid, ethylene glycol and phosphoric acid. The morphology and crystallinity of the obtained nanotubes were investigated by means of electron microscopy and it was found that nanotubes have a constant outer diameter of 200 nm and an internal conical shape where the diameter gradually decreases from 120 nm at the wide end to 50 nm at the narrow end. The transmission electron microscopy investigation defined two different phases of titanium dioxide obtained after annealing of amorphous TiO2 in air at 650 °C and 850 °C. Photocatalytic activity of the samples have been evaluated in methylene blue solution in the presence of dispersed nanotubes under visible and UV irradiation by means of UV/Vis spectroscopy. Anatase phase TiO2 shows the best performance degrading 85 % of dye in 25 min under UV illumination, while rutile phase with anatase inclusions shows the best results with a 50 % decay of dye concentration in 25 min under visible light illumination.

scholarly journals Highly Porous and Ultra-Lightweight Aero-Ga2O3: Enhancement of Photocatalytic Activity by Noble Metals

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1985
Author(s):  
Irina Plesco ◽  
Vladimir Ciobanu ◽  
Tudor Braniste ◽  
Veaceslav Ursaki ◽  
Florian Rasch ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Noble Metals ◽  
Hybrid Structures ◽  
Blue Dye ◽  
Light Illumination ◽  
Methylene Blue Dye ◽  
Visible Light Illumination ◽  
New Type ◽  
Highly Porous

A new type of photocatalyst is proposed on the basis of aero-β-Ga2O3, which is a material constructed from a network of interconnected tetrapods with arms in the form of microtubes with nanometric walls. The aero-Ga2O3 material is obtained by annealing of aero-GaN fabricated by epitaxial growth on ZnO microtetrapods. The hybrid structures composed of aero-Ga2O3 functionalized with Au or Pt nanodots were tested for the photocatalytic degradation of methylene blue dye under UV or visible light illumination. The functionalization of aero-Ga2O3 with noble metals results in the enhancement of the photocatalytic performances of bare material, reaching the performances inherent to ZnO while gaining the advantage of the increased chemical stability. The mechanisms of enhancement of the photocatalytic properties by activating aero-Ga2O3 with noble metals are discussed to elucidate their potential for environmental applications.

Photocatalytic Degradation of Methylene Blue over Co-Ag3VO4 under Visible Light Irradiation

2011 ◽  
Vol 335-336 ◽  
pp. 1385-1390 ◽  
Author(s):  
Shuo Wiei Zhao ◽  
Hui Xu ◽  
Hua Ming Li ◽  
Yuan Guo Xu
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Absorption Edge ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Light Irradiation ◽  
Experimental Conditions ◽  
X Ray

In order to improve the photocatalytic activity, Co was successfully loaded into Ag3VO4 by using impregnation process. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectroscopy (DRS). The XRD and SEM–EDS analyses revealed that Co ion was dispersed on Ag3VO4. The DRS results indicated that the absorption edge of the Co–Ag3VO4 catalyst shifted to longer wavelength. The enhanced photocatalytic activity of Co–Ag3VO4 for Methylene Blue(MB) dye degradation under visible light irradiation was due to its wider absorption edge and higher separation rate of photo-generated electron and holes. In the experimental conditions, it is demonstrated that the MB was effectively degraded by more than 95% within 40 min when the Co–Ag3VO4 catalyst was calcined at 300°C with 1 wt.% Co content.

In-situ fabrication of Ag/P-g-C3N4 composites with enhanced photocatalytic activity for sulfamethoxazole degradation

2019 ◽  
Vol 366 ◽  
pp. 219-228 ◽  
Author(s):  
Miao Chen ◽  
Changsheng Guo ◽  
Song Hou ◽  
Linlin Wu ◽  
Jiapei Lv ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
In Situ Fabrication

scholarly journals In situ Fabrication of α-Bi2O3/(BiO)2CO3 Nanoplate Heterojunctions with Tunable Optical Property and Photocatalytic Activity

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Yu Huang ◽  
Wei Wang ◽  
Qian Zhang ◽  
Jun-ji Cao ◽  
Ru-jin Huang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Optical Property ◽  
In Situ Fabrication

scholarly journals In Situ Construction of a MgSn(OH)6 Perovskite/SnO2 Type-II Heterojunction: A Highly Efficient Photocatalyst towards Photodegradation of Tetracycline

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 53 ◽  
Author(s):  
Yuanyuan Li ◽  
Xiaofang Tian ◽  
Yaoqiong Wang ◽  
Qimei Yang ◽  
Yue Diao ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Ultraviolet Irradiation ◽  
Photocatalytic Oxidation ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Active Species ◽  
Growth Strategy ◽  
Type Ii ◽  
Highly Efficient

Using solar energy to remove antibiotics from aqueous environments via photocatalysis is highly desirable. In this work, a novel type-II heterojunction photocatalyst, MgSn(OH)6/SnO2, was successfully prepared via a facile one-pot in situ hydrothermal method at 220 °C for 24 h. The obtained heterojunctions were characterized via powder X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic performance was evaluated for photodegradation of tetracycline solution under ultraviolet irradiation. The initial concentration of tetracycline solution was set to be 20 mg/L. The prepared heterojunctions exhibited superior photocatalytic activity compared with the parent MgSn(OH)6 and SnO2 compounds. Among them, the obtained MgSn(OH)6/SnO2 heterojunction with MgCl2·6H2O:SnCl4·5H2O = 4:5.2 (mmol) displayed the highest photocatalytic performance and the photodegradation efficiency conversion of 91% could be reached after 60 min under ultraviolet irradiation. The prepared heterojunction maintained its performance after four successive cycles of use. Active species trapping experiments demonstrated that holes were the dominant active species. Hydroxyl radicals and superoxide ions had minor effects on the photocatalytic oxidation of tetracycline. Photoelectrochemical measurements were used to investigate the photocatalytic mechanism. The enhancement of photocatalytic activity could be assigned to the formation of a type-II junction photocatalytic system, which was beneficial for efficient transfer and separation of photogenerated electrons and holes. This research provides an in situ growth strategy for the design of highly efficient photocatalysts for environmental restoration.

scholarly journals Investigating Methylene Blue Adsorption and Photocatalytic Activity of ZnO/CNC Nanohybrids

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Vu Nang An ◽  
Tran T. T. Van ◽  
Ha T. C. Nhan ◽  
Le Van Hieu
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Concentration Ratio ◽  
Low Cost ◽  
Nitrogen Adsorption ◽  
Ion Concentration ◽  
Strong Absorption Band ◽  
Pure Cellulose ◽  
Nypa Fruticans ◽  
Bet Analysis

Nanohybrids of zinc oxide/cellulose nanocrystals (ZnO/CNCs) were successfully prepared by using a low cost and green method for adsorption and photocatalytic degradation of methylene blue (MB). CNCs have been derived through the hydrolysis reaction by citric/hydrochloric acid from the pure cellulose isolated from Vietnamese Nypa fruticans trunk. The influence of the Zn2+ ion concentration on the morphology, microstructure, and thermal properties as well as the photocatalytic activity of the ZnO/CNC nanohybrids was investigated in detail. Analyses of FTIR spectra, XRD, and SEM indicated that the ZnO nanocrystals with the size of 50 nm formed and loaded on the surface of CNC. Based on the DRS spectra and the nitrogen adsorption–desorption isotherms (BET) analysis, the absorption of ultraviolet light with a strong absorption band around 400 nm was found for all the ZnO/CNC nanohybrids, and the values of specific surface areas (SBET) of materials can be controlled by changing the concentration ratio of Zn2+ ion and CNC. The TGA analysis demonstrated that the ZnO loading samples (ZnO/CNC) had the thermal degradation onset temperature higher than that of neat CNC. The effect of MB removal showed the results which were contributed not only by the adsorption ability of CNC but also by the photocatalytic activity of ZnO. The photocatalytic efficiency significantly depended on the content of ZnO loading. The maximum degradation of MB was about 95% in 150 min for the ZnO/CNC-1.0 sample in which the concentration ratio of zinc-precursor Zn(NO3)2·6H2O and CNC was 1.0.

Investigation of Surface Tension Effects of a Water-Hexadecane Interface on Silicon Microparts

2011 ◽  
Author(s):  
Caroline E. Liberti ◽  
Nathan B. Crane
Keyword(s):  
Surface Tension ◽  
Low Cost ◽  
Photovoltaic Cells ◽  
In Situ Fabrication ◽  
Recent Interest

Assembly at sub-millimeter dimensions is a challenging process that is often not economically feasible. This limits many systems to in-situ fabrication from compatible materials. If freed from these limitations on processes and materials, it might be possible to improve microsystem performance. One critical application of recent interest is in the assembly of small crystalline photovoltaic cells onto low-cost and possibly flexible modules [1].

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