scholarly journals Photocatalytic activity enhancement for removal of dye molecules based on plasmonic Ag grafted TiO2 nanocubes under visible light driven

2020 ◽  
Vol 23 (4) ◽  
pp. 743-751
Author(s):  
Ton Nu Quynh Trang ◽  
Le Thi Ngoc Tu ◽  
Tran Van Man ◽  
Vu Thi Hanh Thu
Keyword(s):  
Visible Light ◽  
Environmental Remediation ◽  
High Efficiency ◽  
Uv Light ◽  
Synergistic Effects ◽  
Light Response ◽  
Ag Nps ◽  
X Ray ◽  
Visible Light Driven ◽  
Carrier Separation

Introduction: Finding a novel photocatalyst for photocatalytic degradation operating in the wavelength range from UV to visible light has been considered a great potential for environmental remediation. Herein, TiO2 nanocubics (NCs) decorated Ag nanoparticles (NPs) with various concentrations were developed. Methods: The crystal structure, morphological and chemical characteristics of prepared photocatalysts were thoroughly analyzed by a series of main analyses (X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and UVVis spectra). Results: The results revealed that a significantly promoting visible-light photocatalytic behavior of TiO2NCs@Ag photocatalyst was observed. The photocatalytic methyl orange (MO) degradation of the as-synthesized Ag anchored TiO2NCs photocatalyst (85% and 62% under UV light and visible light, respectively) exhibited outstanding photocatalytic efficacy compared with pristine TiO2 NCs. The achieved results could be assigned to the synergistic effects between TiO2NCs and Ag- NPs, leading to enhanced charge carrier separation and improved absorption ability in visible-light response. Conclusion: This work facilitates designing and developing high-efficiency heterostructure photocatalysts for practical works related to environmental deterioration.

scholarly journals Core-Shell Heterostructured and Visible-Light-Driven Titanoniobate/TiO2 Composite for Boosting Photodegradation Performance

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1503 ◽  
Author(s):  
Chao Liu ◽  
Xin Gao ◽  
Zitong Han ◽  
Yao Sun ◽  
Yue Feng ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Environmental Remediation ◽  
Synergistic Effects ◽  
Light Response ◽  
Core Shell ◽  
Photogenerated Electrons ◽  
Visible Light Driven ◽  
Degradation Activity ◽  
Calcination Method

Herein, we report a one-dimensional (1D) S-doped K3Ti5NbO14@TiO2 (STNT) core-shell heterostructured composite with an enhanced photocatalytic degradation activity under visible light, which was prepared by a simple reassembly-calcination method using thiourea as the S source. The anisotropically shaped rods are favorable for the rapid transport of photogenerated charge carriers. The substitution of Ti4+ by S6+ is primarily incorporated into the lattice of the TiO2 shell so as to create an intra-band-gap state below the conduction band (CB) position, giving rise to Ti−O−S bonds and thus the visible light response. The presence of electron-deficient S atoms is of benefit to the decreased recombination rate of photogenerated electrons and holes by capturing electrons (e−). Meanwhile, a tight close interface between K3Ti5NbO14 and TiO2 was formed to achieve a nano-heterojunction structure, leading to the fostered separation of its interfacial photogenerated electrons and holes. The visible-light-driven photocatalytic degradation of methylene blue (MB) by STNT composites is higher than that by pure K3Ti5NbO14, owing to the synergistic effects of S doping and heterojunction. A possible photocatalytic mechanism was proposed with a reasonable discussion. This work may provide an insight into constructing highly efficient core-shell photocatalysts used toward sustainable environmental remediation and resource shortages.

scholarly journals Photocatalytic Decomposition of Gaseous HCHO over Ag Modified TiO2 Nanosheets at Ambient Temperature

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 338 ◽  
Author(s):  
Xueding Jiang ◽  
Weicheng Xu ◽  
Lian Yu
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Oxidation ◽  
Synergistic Effects ◽  
Resonance Effect ◽  
Light Response ◽  
Photocatalytic Decomposition ◽  
Metallic State ◽  
Ag Nps ◽  
Tio2 Nanosheets

Ag nanoparticles loaded onto TiO2 nanosheets with exposed {001} facets were synthesized by solvothermal hydrolysis and photoreduction deposition methods. The results suggested that Ag NPs were uniformly dispersed on the surface of anatase TiO2 NSs with a metallic state. The Raman scattering and visible light absorption performances of Ag/TiO2 NSs were enhanced by Ag NPs due to their surface plasmon resonance effect. Photocatalytic oxidation experiments for HCHO were carried out under visible light, and the enhanced photocatalytic activity of Ag/TiO2 NSs can be attributed to the synergistic effects of the following factors: (1) the {001} facets, which possessed higher surface energy, showed higher photocatalytic activity; (2) the Ag NPs, the increased oxygen vacancies, and O2 adsorption on {001} facets can trap photoelectrons, thus inhibiting the recombination of photoelectrons and holes; (3) the Ag NPs can extend the light response range of TiO2 into visible light. The in situ FTIR results showed that higher mineralization efficiency of HCHO was achieved on Ag/TiO2 NSs than on Ag/TiO2 NPs. Additionally, the mechanism for HCHO photocatalytic oxidation was also discussed.

scholarly journals Photocatalytic Degradation of Diazinon with a 2D/3D Nanocomposite of Black Phosphorous/Metal Organic Framework

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 679
Author(s):  
Philani V. Hlophe ◽  
Langelihle N. Dlamini
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Environmental Remediation ◽  
Electrochemical Impedance ◽  
Solar Spectrum ◽  
Black Phosphorus ◽  
X Ray ◽  
Visible Light Driven ◽  
Metal Organic

Metal–organic frameworks (MOFs) are promising materials for the removal and photodegradation of pesticides in water. Characteristics such as large surface area, crystalline structure and catalytic properties give MOFs an advantage over other traditional adsorbents. The application of MOFs in environmental remediation is hindered by their ability to only absorb in the UV region. Therefore, combining them with an excellent charge carrier 2D material such as black phosphorus (BP) provides an attractive composite for visible-light-driven degradation of pesticides. In the study, a nanocomposite of black phosphorus and MIL-125(Ti), defined as BpMIL, was prepared using a two-stage hydrothermal and sonication route. The as-prepared composite was characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) spectroscopy. These techniques revealed that the circular and sheet-like morphology of the nanocomposites had minimum charge recombination, allowing them to be effective photocatalysts. Furthermore, the photocatalysts exhibited extended productive utilization of the solar spectrum with inhibited recombination rate and could be applied in visible-light-driven water treatment. The photodegradation of diazinon in water was studied using a series of BpMIL (4%, 6% and 12% by mass) nanocomposites as a photocatalyst. The optimal composite was determined to be 4%BpMIL. The degradation parameters were optimized and these included photocatalyst dosage, initial diazinon concentration and pH of the solution. The optimal conditions for the removal and degradation of diazinon were: neutral pH, [diazinon] = 20 mg/L, photocatalyst dosage = 0.5 g/L, achieving 96% removal of the pesticide after 30 min with 4%BpMIL, while MIL-125(Ti) showed 40% removal. The improved photodegradation efficiency of the 4%BpMIL composite was attributed to Ti3+-Ti4+ intervalence electron transfer and the synergistic effect between MIL-125(Ti) and BP. The photodegradation followed pseudo-first-order kinetics with a rate constant of 1.6 × 10−2 min−1.

scholarly journals N-Doped K3Ti5NbO14@TiO2 Core-Shell Structure for Enhanced Visible-Light-Driven Photocatalytic Activity in Environmental Remediation

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 106 ◽  
Author(s):  
Xin Gao ◽  
Chen Wang ◽  
Qixiang Xu ◽  
Hongjie Lv ◽  
Ting Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Environmental Remediation ◽  
Titanium Isopropoxide ◽  
Core Shell ◽  
Xps Spectra ◽  
X Ray ◽  
Visible Light Driven ◽  
N Doping

A novel N-doped K3Ti5NbO14@TiO2 (NTNT) core-shell heterojunction photocatalyst was synthesized by firstly mixing titanium isopropoxide and K3Ti5NbO14 nanobelt, and then calcinating at 500 °C in air using urea as the nitrogen source. The samples were analyzed by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis absorption spectroscopy and X-ray photoelectron spectroscopic (XPS) spectra. Anatase TiO2 nanoparticles were closely deposited on the surface of K3Ti5NbO14 nanobelt to form a nanoscale heterojunction structure favorable for the separation of photogenerated charge carriers. Meanwhile, the nitrogen atoms were mainly doped in the crystal lattices of TiO2, resulting in the increased light harvesting ability to visible light region. The photocatalytic performance was evaluated by the degradation of methylene blue (MB) under visible light irradiation. The enhanced photocatalytic activity of NTNT was ascribed to the combined effects of morphology engineering, N doping and the formation of heterojunction. A possible photocatalytic mechanism was proposed based on the experimental results.

scholarly journals Facile Synthesis of Heterojunctioned ZnO/Bi2S3 Nanocomposites for Enhanced Photocatalytic Reduction of Aqueous Cr(VI) under Visible-Light Irradiation

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 624 ◽  
Author(s):  
Xiaoya Yuan ◽  
Xue Wu ◽  
Zijuan Feng ◽  
Wen Jia ◽  
Xuxu Zheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Environmental Remediation ◽  
High Efficiency ◽  
Diffuse Reflectance Spectroscopy ◽  
Structured Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Facile Solvothermal Method

Heterojunctioned ZnO/Bi2S3 nanocomposites were prepared via a facile solvothermal method. The obtained photocatalysts were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), and Photoelectrochemical and Photoluminescence spectroscopy (PL), respectively. The results showed that ZnO/Bi2S3 composites exhibited the sandwiched-like structure, where ZnO nanoparticles were randomly embedded between Bi2S3 nanoflakes. The performance of photocatalytic Cr(VI) reduction under visible light indicated that ZnO/Bi2S3 composites exhibited high-efficiency photocatalytic activity in comparison with either Bi2S3 or ZnO. The 5%-ZnO/Bi2S3 photocatalyst removed 96% of Cr(VI) within 120 min at 20 mg/L initial concentration of Cr(VI). The enhanced performance of ZnO/Bi2S3 photocatalysts could be ascribed to the increased light harvesting and the effective separation and transfer of the photogenerated charge carriers across the heterojunction interface of the ZnO/Bi2S3 composite. This work could pave the way for the design of new hetero-structured materials and has great potential in environmental remediation.

Au nanoparticle homogeneously decorated C@TiO2 for enhanced visible-light-driven photocatalytic activity

RSC Advances ◽  
2015 ◽  
Vol 5 (126) ◽  
pp. 103790-103796 ◽  
Author(s):  
Yan-Zhen Zheng ◽  
Yan-Yan Xu ◽  
Hua-Bin Fang ◽  
Yuan Wang ◽  
Xia Tao
Keyword(s):  
Photocatalytic Activity ◽  
Charge Carrier ◽  
Visible Light ◽  
Light Response ◽  
Au Nanoparticle ◽  
Transport Efficiency ◽  
Response Characteristics ◽  
Visible Light Response ◽  
Visible Light Driven ◽  
Carrier Separation

A Au–C@TiO2 photocatalyst shows excellent visible-light response characteristics and promotes charge carrier separation and transport efficiency.

scholarly journals Improved Visible-Light Photocatalytic Activity of g-C3N4/CuWO4 Nanocomposite for Degradation of Methylene Blue

Proceedings ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 43
Author(s):  
Afsaneh Rashidizadeh ◽  
Hossein Ghafuri ◽  
Zeynab Rezazadeh
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Solar Energy ◽  
Visible Light ◽  
Environmental Remediation ◽  
High Efficiency ◽  
Hydrothermal Process ◽  
Co2 Reduction ◽  
High Rate ◽  
Visible Light Driven

In recent years, heterogeneous semiconductor photocatalysts have attracted great attention in the arena of environmental remediation and solar energy conversion; because, sunlight energy is a renewable, cheap, and accessible source of energy and also converting solar energy to chemical energy can be declined the energy crisis and global warming. Development of visible light heterogeneous photocatalysts with high efficiency and chemical stability is important for catalysis researchers. Among different types of semiconductor material, polymeric graphitic carbon nitride (g-C3N4) with a medium band gap of about 2.7 eV has been widely applied in photodegradation of organic pollutants, water splitting, CO2 reduction, solar cells, energy storage, and organic synthesis. Unfortunately, due to the high rate recombination of photoinduced carriers, the photocatalytic performance of the bare g-C3N4 is still poor. Hence, many strategies including metal doping, noble metal deposition, and coupling with semiconductor composites have been employed to modify g-C3N4. Herein, we report the synthesis of g-C3N4/CuWO4 nanocomposite via a hydrothermal process. The prepared visible-light-driven nanocomposite exhibited an enhanced photocatalytic activity compared with bare g-C3N4 for the degradation of methylene blue (MB) under LED light irradiation.

Construction of hollow In2S3/CdIn2S4 heterostructures with high efficiency for Cr(vi) reduction

2021 ◽  
Author(s):  
Cheng Cheng ◽  
Dongyun Chen ◽  
Najun Li ◽  
Hua Li ◽  
Qingfeng Xu ◽  
...  
Keyword(s):  
Visible Light ◽  
High Efficiency ◽  
Visible Light Driven

A hollow constructed photocatalyst, In2S3/CdIn2S4, was synthesized for visible-light-driven Cr(vi) reduction.

Green synthesized Ag-TiO2 for degradation of organic dye through visible light driven photo-reactor and its kinetics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Titikshya Mohapatra ◽  
Sakshi Manekar ◽  
Vijyendra Kumar Sahu ◽  
Ashwini Kumar Soni ◽  
Sudip Banerjee ◽  
...  
Keyword(s):  
Visible Light ◽  
Mangifera Indica ◽  
Band Gap Energy ◽  
Photo Degradation ◽  
X Ray ◽  
Green Approach ◽  
Vis Spectroscopy ◽  
Rate Of Reaction ◽  
Visible Light Driven ◽  
Modification Of Titanium

Abstract This study reports a green approach for the modification of titanium dioxide (TiO2) nanoparticles with immobilization of silver nanoparticles. One of the natural sources i.e., Mangifera indica leaf extract was utilized as reducing and capping agent for the fabrication of Ag-TiO2 nanocatalyst. Further, the surface morphology and band-gap energy of prepared Ag-TiO2 were analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and UV–Vis spectroscopy. Also, it was characterized by X-ray Powder Diffraction (XRD) which provides the information regarding the crystallinity of the Ag-TiO2. Subsequently, photo activity of Ag-TiO2 was investigated for the degradation of methylene blue (MB) dye wastewater through visible light driven photoreactor. The Ag-TiO2 provided highest (68%) of photo-degradation efficiency within 110 min for 7.81 × 10−5 mol/L initial MB concentration at pH 8 by using 0.19 g/L photocatalyst. Further, addition of 10 mM H2O2 boost up the MB photodegradation to 74%. The kinetic study confirmed the MB degradation followed first order rate of reaction.

scholarly journals Ionic Liquid-Assisted Synthesis of Ag3PO4 Spheres for Boosting Photodegradation Activity under Visible Light

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 788
Author(s):  
Beibei Zhang ◽  
Lu Zhang ◽  
Yulong Zhang ◽  
Chao Liu ◽  
Jiexiang Xia ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Visible Light ◽  
High Efficiency ◽  
Chemical Precipitation ◽  
Active Species ◽  
Precipitation Method ◽  
Dihydrogen Phosphate ◽  
Xrd Pattern ◽  
Simple Chemical ◽  
Visible Light Driven

In this work, a simple chemical precipitation method was employed to prepare spherical-like Ag3PO4 material (IL-Ag3PO4) with exposed {111} facet in the presence of reactive ionic liquid 1-butyl-3-methylimidazole dihydrogen phosphate ([Omim]H2PO4). The crystal structure, microstructure, optical properties, and visible-light photocatalytic performance of as-prepared materials were studied in detail. The addition of ionic liquids played a crucial role in forming spherical-like morphology of IL-Ag3PO4 sample. Compared with traditional Ag3PO4 material, the intensity ratio of {222}/{200} facets in XRD pattern of IL-Ag3PO4 was significantly enhanced, indicating the main {111} facets exposed on the surface of IL-Ag3PO4 sample. The presence of exposed {111} facet was advantageous for facilitating the charge carrier transfer and separation. The light-harvesting capacity of IL-Ag3PO4 was larger than that of Ag3PO4. The photocatalytic activity of samples was evaluated by degrading rhodamine B (RhB) and p-chlorophenol (4-CP) under visible light. The photodegradation efficiencies of IL-Ag3PO4 were 1.94 and 2.45 times higher than that of Ag3PO4 for RhB and 4-CP removal, respectively, attributing to a synergy from the exposed {111} facet and enhanced photoabsorption. Based on active species capturing experiments, holes (h+), and superoxide radical (•O2−) were the main active species for visible-light-driven RhB photodegradation. This study will provide a promising prospect for designing and synthesizing ionic liquid-assisted photocatalysts with a high efficiency.

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