scholarly journals Photocatalytic Adsorption Synergistic Degradation of Tetracycline by Z-scheme Bi2WO6/ZIF-8

2021 ◽  
Author(s):  
Xiaojun Dai ◽  
sheng feng ◽  
Wei Wu ◽  
Yun Zhou ◽  
Zhiwei Ye ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Photogenerated Electron ◽  
Utilization Efficiency ◽  
Electron Hole ◽  
Effects Of Ph ◽  
Growth Method ◽  
Synergistic Degradation ◽  
First Time

Abstract In this paper, in order to improved the photocatalytic activity of Bi2WO6, Bi2WO6 and ZIF-8 were successfully combined by in-situ growth method for the first time. The addition of ZIF-8 effectively inhibited the recombination of photogenerated electron hole pairs and further improved the electron utilization efficiency, and superoxide anion was introduced to greatly improve the photocatalytic activity. The performance of Bi2WO6/ZIF-8 in the photodegradation of tetracycline (TC) was studied under different conditions of proportions of ZIF-8, dosage of catalyst and concentration of TC. The results indicated that B/Z/5/1 (10mg) had the best photocatalytic activity, and 97.8% of TC (20mg/L) could be degraded in 80 minutes under UV light, the rate constant (k) for TC degradation was almost 3 times that of Bi2WO6. The effects of pH, HA and inorganic anions on the degradation of TC were studied in simulated real water. Further, B/Z/5/1 could be reutilized up to five cycles without reduction of efficiency and catalysis performance. Therefore, Bi2WO6/ZIF-8 heterojunction composite material can be utilized as an efficient photocatalyst for remediation of environmental pollution.

scholarly journals Bi/BiOCl Nanosheets Enriched with Oxygen Vacancies to Enhance Photocatalytic CO2 Reduction

2021 ◽  
Author(s):  
Shuqi Wu ◽  
Junbu Wang ◽  
Qingchuan Li ◽  
Zeai Huang ◽  
Zhiqiang Rao ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Noble Metals ◽  
Oxygen Vacancies ◽  
Separation Efficiency ◽  
Co2 Reduction ◽  
Photogenerated Electron ◽  
In Situ Reduction ◽  
Electron Hole

AbstractBiOCl has been used in the photoreduction of CO2, but exhibits limited photocatalytic activity. In this study, Bi was in situ reduced and deposited on the surface of (001)-dominated BiOCl nanosheets by NaBH4 to form Bi/BiOCl nanosheets enriched with oxygen vacancies. The as-prepared Bi/BiOCl nanosheets having low thickness (ca. 10 nm) showed much higher concentration of oxygen vacancies compared to Bi/BiOCl nanoplates having high thickness (ca. 100 nm). Subsequently, the photocatalytic activity of the Bi/BiOCl nanosheets enriched with oxygen vacancies for CO2 reduction was dramatically enhanced and much higher than that of BiOCl nanoplates, nanosheets, and Bi/BiOCl nanoplates. It showed that the improved photocatalytic activity in the reduction of CO2 can be attributed to the enhanced separation efficiency of photogenerated electron–hole pairs of the oxygen vacancies on BiOCl nanosheets and Bi metals. This work demonstrated that the in situ reduction of non-noble metals on the surface of BiOCl nanosheets that are enriched with oxygen vacancies is favorable for increasing photocatalytic CO2 reduction.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

In-situ cellulose-framework templates mediated monodispersed silver nanoparticles via facile UV-light photocatalytic activity for anti-microbial functionalization

2021 ◽  
pp. 118255
Author(s):  
Sung Won Ko ◽  
Ji Yeon Lee ◽  
Abdelrahman I. Rezk ◽  
Chan Hee Park ◽  
Cheol Sang Kim
Keyword(s):  
Silver Nanoparticles ◽  
Photocatalytic Activity ◽  
Uv Light

scholarly journals A Review on Metal Ions Modified TiO2 for Photocatalytic Degradation of Organic Pollutants

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1039
Author(s):  
Dafu Jiang ◽  
Tunmise Ayode Otitoju ◽  
Yuanyuan Ouyang ◽  
Noor Fazliani Shoparwe ◽  
Song Wang ◽  
...  
Keyword(s):  
Metal Ions ◽  
Active Sites ◽  
Crystal Surface ◽  
Uv Light ◽  
Photogenerated Electron ◽  
Tio2 Photocatalyst ◽  
Electron Hole ◽  
Visible Light Range ◽  
Low Toxicity ◽  
High Chemical Stability

TiO2 is a semiconductor material with high chemical stability and low toxicity. It is widely used in the fields of catalysis, sensing, hydrogen production, optics and optoelectronics. However, TiO2 photocatalyst is sensitive to ultraviolet (UV) light; this is why its photocatalytic activity and quantum efficiency are reduced. To enhance the photocatalytic efficiency in the visible light range as well as to increase the number of the active sites on the crystal surface or inhibit the recombination rate of photogenerated electron–hole pairs electrons, various metal ions were used to modify TiO2. This review paper comprehensively summarizes the latest progress on the modification of TiO2 photocatalyst by a variety of metal ions. Lastly, the future prospects of the modification of TiO2 as a photocatalyst are proposed.

Photocatalytic Removal of 2,4-D Herbicide on Lanthanum Oxide-Modified Titanium Dioxide

2015 ◽  
Vol 1112 ◽  
pp. 168-171
Author(s):  
Wai Ruu Siah ◽  
Nur Azmina Roslan ◽  
Hendrik O. Lintang ◽  
Mustaffa Shamsuddin ◽  
Leny Yuliati
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Inductively Coupled Plasma ◽  
Lanthanum Oxide ◽  
Electrochemical Impedance ◽  
Uv Light ◽  
Photogenerated Electron ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
Impregnation Method

Titanium dioxide (TiO2) has been recognized as an active photocatalyst for degradation of various organic pollutants. In this study, in order to improve the photocatalytic activity of TiO2, the effect of lanthanum oxide modification was investigated by using commercial P25 as the benchmark. Lanthanum oxide/P25 TiO2 composites with 0.1, 0.5, 1 and 5 mol% of La loadings were prepared via an impregnation method. The resultant composites were characterized by X-ray diffraction (XRD), UV-Vis absorption spectroscopy, transmission electron microscopy (TEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and electrochemical impedance spectroscopy (EIS). It was confirmed that the addition of lanthanum oxide did not much affect the crystallinity, crystal structure and the morphology of P25 TiO2. The catalytic activities of the lanthanum oxide/P25 TiO2 catalysts were tested by using 2,4-dichlorophenoxyacetic acid (2,4-D) as the test pollutant and UV light as the irradiation source. The reaction was caried out for 1 hour at room temperature and the percentage removal was determined using a UV spectrophotometer. The results showed that La loading was an important factor that influenced the photocatalytic activity of the composites. After 1 hour reaction, the best catalyst with 0.1 mol% of La loading showed 24% higher photocatalytic activity than the unmodified P25 TiO2 catalyst. It is shown by EIS that the enhanced photocatalytic activity of the composites was due to the ability of lanthanum oxide in improving the charge separation of the photogenerated electron-hole pairs in TiO2.

Photocatalytic properties of Bi/BiOCl heterojunctions synthesized using an in situ reduction method

2014 ◽  
Vol 38 (10) ◽  
pp. 4913-4921 ◽  
Author(s):  
Jiajia Hu ◽  
Guangqing Xu ◽  
Jinwen Wang ◽  
Jun Lv ◽  
Xinyi Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Reduction Method ◽  
Uv Light ◽  
Photocatalytic Properties ◽  
In Situ Reduction ◽  
Light Activity ◽  
Bi Nanoparticles

Bi nanoparticles on BiOCl nanosheets, synthesized via in situ reduction, enhance the UV light photocatalytic activity and achieve visible light activity.

scholarly journals CMOS Image Sensors and Plasma Processes: How PMD Nitride Charging Acts on the Dark Current

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5534
Author(s):  
Yolène Sacchettini ◽  
Jean-Pierre Carrère ◽  
Romain Duru ◽  
Jean-Pierre Oddou ◽  
Vincent Goiffon ◽  
...  
Keyword(s):  
Dark Current ◽  
Uv Light ◽  
Degradation Mechanism ◽  
Nitride Layer ◽  
Image Sensors ◽  
Electron Hole ◽  
Cmos Image Sensors ◽  
Depth Analysis

Plasma processes are known to be prone to inducing damage by charging effects. For CMOS image sensors, this can lead to dark current degradation both in value and uniformity. An in-depth analysis, motivated by the different degrading behavior of two different plasma processes, has been performed in order to determine the degradation mechanisms associated with one plasma process. It is based on in situ plasma-induced charge characterization techniques for various dielectric stack structures (dielectric nature and stack configuration). A degradation mechanism is proposed, highlighting the role of ultraviolet (UV) light from the plasma in creating an electron hole which induces positive charges in the nitride layer at the wafer center, and negative ones at the edge. The trapped charges de-passivate the SiO2/Si interface by inducing a depleted interface above the photodiode, thus emphasizing the generation of dark current. A good correlation between the spatial distribution of the total charges and the value of dark current has been observed.

In situ growth and optical gas adsorption performance of Zn(ii) metal–organic framework membranes at room temperature

The Analyst ◽  
2019 ◽  
Vol 144 (16) ◽  
pp. 4887-4896 ◽  
Author(s):  
Mariyemu Tuergong ◽  
Patima Nizamidin ◽  
Abliz Yimit ◽  
Rena Simayi
Keyword(s):  
Room Temperature ◽  
Gas Adsorption ◽  
Uv Light ◽  
Metal Organic Framework ◽  
Adsorption Behaviors ◽  
Uv Light Irradiation ◽  
Unit Surface ◽  
Metal Organic ◽  
First Time

The optical gas adsorption behaviors of [Zn2(bdc)2(dpNDI)]n membranes were studied for the first time. Under UV light irradiation, they exhibited a greater adsorption response to xylene gas with adsorption capacity of 6.46 μg cm−2 per unit surface.

Synthesis of TiO2-Reduced Graphene Oxide Nanocomposites Offering Highly Enhanced Photocatalytic Activity

2019 ◽  
Vol 19 (11) ◽  
pp. 7089-7096 ◽  
Author(s):  
Wufa Li ◽  
Xiaohong Yang ◽  
Haitao Fu ◽  
Xizhong An ◽  
Haiyang Zhao
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Environmental Remediation ◽  
Hydrothermal Reaction ◽  
Photogenerated Electron ◽  
Electron Hole ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
Hole Recombination

Photogenerated electron–hole recombination significantly restricts the catalytic efficiency of titanium dioxide (TiO2). Various approaches have been developed to overcome this problem, yet it remains challenging. Recently, graphene modification of TiO2 has been considered as an effective alternative to prevent electron–hole recombination and consequently enhance the photocatalytic performance of TiO2. This study reports an efficient but simple hydrothermal method utilizing titanium (IV) butoxide (TBT) and graphene oxide (GO) to prepare TiO2-reduced graphene oxide (RGO) nanocomposites under mild reaction conditions. This method possesses several advantageous features, including no requirement of high temperature for TiO2 crystallization and a one-step hydrothermal reaction for mild reduction of GO without a reducing agent, which consequently makes the production of TiO2-RGO nanocomposites possible in a green and an efficient synthetic route. Moreover, the as-synthesized nanocomposites were characterized by numerous advanced techniques (SEM, TEM, BET, XRD, XPS, and UV-vis spectroscopy). In particular, the photocatalytic activities of the synthesized TiO2-RGO nanocomposites were evaluated by degrading the organic molecules (methylene blue, MB), and it was found that the photocatalytic activity of TiO2-RGO nanocomposites is ~4.5 times higher compared to that of pure TiO2. These findings would be useful for designing reduced graphene oxide-metal oxide hybrids with desirable functionalities in various applications for energy storage devices and environmental remediation.

One-pot low-temperature synthesis of TiO2 nanowire/rGO composites with enhanced photocatalytic activity

RSC Advances ◽  
2016 ◽  
Vol 6 (96) ◽  
pp. 94092-94097 ◽  
Author(s):  
Huan Xing ◽  
Wei Wen ◽  
Jin-Ming Wu
Keyword(s):  
Photocatalytic Activity ◽  
Reaction Rate ◽  
Uv Light ◽  
Reaction Rate Constant ◽  
Light Illumination ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
One Pot ◽  
Tio2 Nanowire

In situ growth of TiO2 nanowires on graphene oxide was achieved at 80 °C in an open atmosphere. The optimized TiO2/rGO hybrid exhibited a reaction rate constant 5.5 times that of TiO2 nanowires towards photodegradations of rhodamine B in water under the UV light illumination.

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