scholarly journals Curcumin Doped SiO2/TiO2 Nanocomposites for Enhanced Photocatalytic Reduction of Cr (VI) under Visible Light

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 942
Author(s):  
Zhiying Yan ◽  
Zijuan He ◽  
Mi Li ◽  
Lin Zhang ◽  
Yao Luo ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Anatase Phase ◽  
Mesoporous Structure ◽  
Band Gap Energy ◽  
Photocatalytic Reduction ◽  
Light Irradiation ◽  
X Ray

In order to further improve the photocatalytic performance of the SiO2/TiO2 composite under visible light irradiation, curcumin-doped SiO2/TiO2 nanocomposites were synthesized via directly incorporating it into the structure of SiO2/TiO2 during the synthesis using an inexpensive and readily available natural pigment (curcumin) as doping agent. The physicochemical properties of SiO2/TiO2 nanocomposites were characterized in detail by X-ray diffraction, transmission electron microscopy, Fourier transform-infrared spectroscopy, N2 adsorption–desorption isotherms, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectroscopy. The results indicate that all SiO2/TiO2 nanocomposites exhibited an anatase phase with a typical mesoporous structure. It was found that the dope of curcumin in the SiO2/TiO2 composite could decrease the crystal size, slightly improve the specific surface areas, significantly enhance the visible light absorption, and effectively narrow the band gap energy from 3.04 to 10(eV). Compared with bare SiO2/TiO2, the curcumin-doped SiO2/TiO2 resulted in enhanced photocatalytic reduction activity for Cr(VI) under visible light irradiation, and the CTS (12) sample with the appropriate content of curcumin of 12 wt % shows the photocatalytic yield reaching 100% within 2.5 hours, which is larger than CT (12) without silica. This could be attributed to the curcumin doping and the synergetic effects of SiO2 and TiO2 in SiO2/TiO2 nanocomposites.

scholarly journals Noble metal-modified titania with visible-light activity for the decomposition of microorganisms

2018 ◽  
Vol 9 ◽  
pp. 829-841 ◽  
Author(s):  
Maya Endo ◽  
Zhishun Wei ◽  
Kunlei Wang ◽  
Baris Karabiyik ◽  
Kenta Yoshiiri ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Visible Light ◽  
Noble Metal ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Light Irradiation ◽  
Localized Surface Plasmon ◽  
Mycelium Growth ◽  
X Ray

Commercial titania photocatalysts were modified with silver and gold by photodeposition, and characterized by diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM). It was found that silver co-existed in zero valent (core) and oxidized (shell) forms, whereas gold was mainly zero valent. The obtained noble metal-modified samples were examined with regard to antibacterial (Escherichia coli(E. coli)) and antifungal (Aspergillus niger(A. niger),Aspergillus melleus(A. melleus),Penicillium chrysogenum(P. chrysogenum),Candida albicans(C. albicans)) activity under visible-light irradiation and in the dark using disk diffusion, suspension, colony growth (“poisoned food”) and sporulation methods. It was found that silver-modified titania, besides remarkably high antibacterial activity (inhibition of bacterial proliferation), could also decompose bacterial cells under visible-light irradiation, possibly due to an enhanced generation of reactive oxygen species and the intrinsic properties of silver. Gold-modified samples were almost inactive against bacteria in the dark, whereas significant bactericidal effect under visible-light irradiation suggested that the mechanism of bacteria inactivation was initiated by plasmonic excitation of titania by localized surface plasmon resonance of gold. The antifungal activity tests showed efficient suppression of mycelium growth by bare titania, and suppression of mycotoxin generation and sporulation by gold-modified titania. Although, the growth of fungi was hardly inhibited through disc diffusion (inhibition zones around discs), it indicates that gold does not penetrate into the media, and thus, a good stability of plasmonic photocatalysts has been confirmed. In summary, it was found that silver-modified titania showed superior antibacterial activity, whereas gold-modified samples were very active against fungi, suggesting that bimetallic photocatalysts containing both gold and silver should exhibit excellent antimicrobial properties.

Preparation of BiXY(2-X)O3 and its Photocatalytic Degradation of Molasses Fermentation Wastewater under Visible-Light Irradiation

2011 ◽  
Vol 287-290 ◽  
pp. 1640-1645 ◽  
Author(s):  
Min Guang Fan ◽  
Zu Zeng Qin ◽  
Zi Li Liu ◽  
Tong Ming Su
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Active Oxygen Species ◽  
Light Irradiation ◽  
X Ray

A series of BixY(2-x)O3photocatalysts were successfully prepared by a solid-state reaction and were subsequently characterized by powder X-ray diffraction, UV-vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy (XPS). The UV-vis diffuse reflectance spectra revealed that the BixY(2-x)O3samples absorbed light in the visible-light range (400-800 nm). The XPS results indicated that active oxygen species were generated on the Bi1.8Y0.2O3surface, which displayed a higher photocatalytic activity. When using photocatalytic degradation molasses fermentation wastewater as a model reaction, the Bi1.8Y0.2O3showed higher photocatalytic activity in comparison to Bi0.2Y1.8O3under visible-light irradiation.

scholarly journals Design and fabrication of Ag3VO4/g-C3N4 heterostructure photocatalyst for enhanced visible light degradation of various organic pollutants

2021 ◽  
Author(s):  
N Sujatha ◽  
M Meenachi ◽  
S Mohammed Harshulkhanb ◽  
H.H Hegazy
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Light Irradiation ◽  
X Rays ◽  
Hydrothermal Route ◽  
X Ray ◽  
Visible Light Degradation

Abstract In later years, numerous viable photocatalysts have been created in order to illuminate the issues of natural toxins. In this work, heterostructured photocatalysts Ag3VO4/g-C3N4 were prepared by effortless hydrothermal route in order to anchor Ag3VO4 on the surface of the g-C3N4 nanosheets. The prepared samples were fairly characterized using X-ray diffraction (XRD), Energy dispersive analysis of X-rays (EDAX), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-DRS), photoluminescence, and X-ray photoelectron spectroscopy (XPS) techniques. The photocatalytic activity of the samples was evaluated by degrading malachite green (MG) and 2,4 dimethyl phenol (DMP) in aqueous solution under visible light irradiation. Compared with Ag3VO4 and g-C3N4, the heterojuncted photocatalyst 50 wt% Ag3VO4/g-C3N4 exhibits the best activity such as high degradation efficiency (99%), high apparent constant (0.0923 min− 1) and long term stability towards DMP under visible light irradiation. The development of a phase scheme heterojunction between Ag3VO4 and g-C3N4 improved the photocatalytic efficiency of Ag3VO4/g-C3N4 composites. Furthermore, the porous structure of g-C3N4 and the effect of Ag surface plasmon resonance (SPR) speed up the isolation and transfer of electron-hole pairs, reducing the likelihood of recombination.

scholarly journals Enhanced Hydrogen Production over C-Doped CdO Photocatalyst in NaS/NaSO Solution under Visible Light Irradiation

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Quan Gu ◽  
Huaqiang Zhuang ◽  
Jinlin Long ◽  
Xiaohan An ◽  
Huan Lin ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Light Irradiation ◽  
X Ray ◽  
State Process ◽  
Visible Light Photocatalytic

The C-doped CdO photocatalysts were simply prepared by high-temperature solid-state process. The as-prepared photocatalysts were characterized by X-ray powder diffraction (XRD), diffuse reflectance spectroscopy (UV-Vis DRS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the carbon was doped into CdO, resulting in the red-shift of the optical absorption of CdO. The photocatalytic behavior of CdO and C-doped CdO was evaluated under the visible light irradiation by using the photocatalytic hydrogen evolution as a model reaction. The C-doped CdO photocatalysts had higher photocatalytic activity over parent CdO under visible light irradiation. The results indicated that the H2production was due to the existence of CdS and the enhancement of visible light photocatalytic activity of H2production was originated from the doping of carbon into the CdO lattice. The probably reaction mechanism was also discussed and proposed.

scholarly journals Enhanced Photoactivity of Fe + N Codoped Anatase-RutileTiO2Nanowire Film under Visible Light Irradiation

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Kewei Li ◽  
Haiying Wang ◽  
Chunxu Pan ◽  
Jianhong Wei ◽  
Rui Xiong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Synergistic Effects ◽  
Anatase Phase ◽  
Light Irradiation ◽  
Codoped Sample ◽  
X Ray ◽  
Photocatalytic Activities

Rutile-anatase phase mixedFe+Ncodoped TiO2nanowires were designed and prepared by a two-step anodic oxidation method. The results of X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy confirm that the preparedFe+Ncodoped TiO2nanowires exhibit intimately contacted anatase-rutile heterostructure with the rutile content of 21.89%. The X-ray photoelectron spectroscopy measurements show that nitrogen and iron atoms are incorporated into the titania oxide lattice, and the UV-visible absorption spectra show that the codoping of iron and nitrogen atoms could extend the absorption to visible light region. The photocatalytic activities of all the samples were evaluated by photocatalytic degradation of methylene blue under visible light irradiation. TheFe+Ncodoped sample achieves the best response to visible light and the highest photocatalytic activities. The enhancement of photocatalytic activity forFe+Ncodoped sample should be ascribed to the synergistic effects of codoped nitrogen and iron ions and the anatase-rutile heterostructure.

Cu Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity and High Temperature Anatase Stability

2018 ◽  
Author(s):  
Snehamol Mathew ◽  
Priyanka Ganguly ◽  
Stephen Rhatigan ◽  
Vignesh Kumaravel ◽  
Ciara Byrne ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Density Functional ◽  
Anatase Phase ◽  
Sol Gel ◽  
Chemical Properties ◽  
Light Irradiation ◽  
Health Concern ◽  
Bacterial Inactivation ◽  
X Ray

Indoor surface contamination by microbes is a major public health concern. A damp environment is one potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO<sub>2</sub>) can effectively curb this growing threat.<b> </b>Metal-doped titania in anatase phase has been proved as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu) doped TiO<sub>2 </sub>(Cu-TiO<sub>2</sub>) was evaluated against <i>Escherichia coli</i> (Gram-negative) and <i>Staphylococcus aureus</i> (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO<sub>2 </sub>was carried out <i>via</i> sol-gel technique. Cu-TiO<sub>2</sub> further calcined at various temperatures (in the range of 500 °C – 700 °C) to evaluate the thermal stability of TiO<sub>2</sub> anatase phase. The physico-chemical properties of the samples were characterised through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV-visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO<sub>2</sub> was maintained well, up to 650 °C, by the Cu dopant. UV-DRS results suggested that the visible light absorption property of Cu-TiO<sub>2 </sub>was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasises the introduction of Cu<sup>+</sup> and Cu<sup>2+</sup> ions by replacing Ti<sup>4+</sup> ions in the TiO<sub>2</sub> lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9%) was attained in 30 mins of visible light irradiation by Cu-TiO<sub>2</sub>.

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.

scholarly journals Photocatalytic degradation of deoxynivalenol over dendritic-like α-Fe2O3 under visible light irradiation

Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 105 ◽  
Author(s):  
Huiting Wang ◽  
Jin Mao ◽  
Zhaowei Zhang ◽  
Qi Zhang ◽  
Liangxiao Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Synthesis Method ◽  
Light Irradiation ◽  
Trichothecene Mycotoxin ◽  
X Ray

Deoxynivalenol (DON) is a secondary metabolite produced by Fusarium, which is a trichothecene mycotoxin. As the main mycotoxin with high toxicity, wheat, barley, corn and their products are susceptible to contamination of DON. Due to the stability of this mycotoxin, traditional methods for DON reduction often require a strong oxidant, high temperature and high pressure with more energy consumption. Therefore, exploring green, efficient and environmentally friendly ways to degrade or reduce DON is a meaningful and challenging issue. Herein, a dendritic-like α-Fe2O3 was successfully prepared using a facile hydrothermal synthesis method at 160 °C, which was systematically characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). It was found that dendritic-like α-Fe2O3 showed superior activity for the photocatalytic degradation of DON in aqueous solution under visible light irradiation (λ > 420 nm) and 90.3% DON (initial concentration of 4.0 μg/mL) could be reduced in 2 h. Most of all, the main possible intermediate products were proposed through high performance liquid chromatography-mass spectrometry (HPLC-MS) after the photocatalytic treatment. This work not only provides a green and promising way to mitigate mycotoxin contamination but also may present useful information for future studies.

Photocatalytic Decomposition of Methylene Blue with Lanthanum Doping TiO2 under Visible Light Irradiation

2013 ◽  
Vol 734-737 ◽  
pp. 2163-2167
Author(s):  
Guang Xiu Cao ◽  
Zhong Hou Zhang ◽  
Bin Zhai
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Light Irradiation ◽  
Photocatalytic Decomposition ◽  
Lanthanum Doping ◽  
X Ray ◽  
Degradation Rates ◽  
Vis Spectroscopy

Lanthanum doped TiO2 powders were prepared by hydrolysis of titanium tetra-n-butyl oxide and La (NO3)3 in solution. The resulting powders were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis absorption spectroscopy. The photocatalytic activities of doped samples were evaluated by the decomposition of methylene blue under visible light irradiation. The XRD results showed that the doping of lanthanum could not only efficiently inhibit the grain growth but also suppress the phase transition of anatase to rutile. UV-Vis spectroscopy of lanthanum doping TiO2 indicated that the absorption onset red-shifted to the visible light region. XPS results revealed that La2O3 had formed which could enhance the surface area. The degradation rates of methylene blue verified that the visible light photocatalytic activity of TiO2 has been enhanced by the doping of lanthanum.

Photocatalytic properties of p-n heterojunction Ag2CO3/Ag3PO4/Ni thin films under visible light

2019 ◽  
Vol 12 (06) ◽  
pp. 1950085 ◽  
Author(s):  
Di Zhao ◽  
Xuezheng An ◽  
Yaxian Sun ◽  
Guihua Li ◽  
Hongyan Liu ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Light Irradiation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Photodegradation Efficiency

p-n heterojunction Ag2CO3/Ag3PO4/Ni thin films were prepared by electrochemical co-deposition. The surface morphology and structural properties of the thin films were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). The photocatalytic (PC) properties of the Ag2CO3/Ag3PO4/Ni composite thin films were investigated by their ability to degrade rhodamine B (RhB) and Congo red (CR) under visible light irradiation. The results showed that the photodegradation efficiency of RhB by an Ag2CO3/Ag3PO4/Ni thin film under visible-light irradiation for 30[Formula: see text]min (98.84%) was 2.64 times higher than that of an Ag3PO4/Ni thin film and 3.44 times higher than of an Ag2CO3/Ni thin film. The presence of a [Formula: see text]-[Formula: see text] heterojunction greatly increased the charge conductivity of the film and its ability to photocatalytically reduce dissolved oxygen, which are the main reasons for the improved PC performance of the Ag2CO3/Ag3PO4/Ni films.

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