scholarly journals Improving the Performance of ZnS Photocatalyst in Degrading Organic Pollutants by Constructing Composites with Ag2O

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1451
Author(s):  
Dequan Yu ◽  
Hao Fang ◽  
Peikai Qiu ◽  
Fancong Meng ◽  
Haixia Liu ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Organic Pollutants ◽  
Catalytic Mechanism ◽  
Radical Scavenging ◽  
Light Response ◽  
High Catalytic Activity ◽  
Mechanism Study ◽  
Catalytic Rate Constant ◽  
Response Range ◽  
Composite Photocatalysts

ZnS is a promising photocatalyst in water purification, whereas its low photon efficiency and poor visible-light response restrict its application. Constructing composites may help solve these problems. In this work, Ag2O was introduced to ZnS for the first time based on their energy band characteristics to form a novel ZnS/Ag2O composite photocatalyst. In the model reaction of degrading methylene blue, the as-designed catalyst exhibited high catalytic activity among a series of ZnS-based composite photocatalysts under similar conditions. The catalytic rate constant was up to 0.138 min−1, which is 27.4- and 15.6-times higher than those of ZnS and Ag2O. This composite degraded 92.4% methylene blue in 50 min, while the ratios were 31.9% and 68.8% for ZnS and Ag2O. Catalytic mechanism study based on photoluminescence and radical-scavenging experiments revealed that the enhanced photocatalytic activity was attributed to the composite structure of ZnS/Ag2O. The structure not only facilitated the separation and transmission of photogenerated carriers but also extended the light response range of the catalyst. The as-designed ZnS/Ag2O composite is promising in degrading organic pollutants in water.

scholarly journals Efficient Oxidative Removal of Organic Pollutants by Ordered Mesoporous Carbon-Supported Cobalt Phthalocyanine

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yi Chen ◽  
Yan Gu ◽  
Nan Li ◽  
Wangyang Lu ◽  
Wenxing Chen
Keyword(s):  
Organic Pollutants ◽  
Mesoporous Carbon ◽  
Catalytic Mechanism ◽  
Epoxy Compound ◽  
Ordered Mesoporous Carbon ◽  
High Catalytic Activity ◽  
Trimethylammonium Chloride ◽  
Catalytic Systems ◽  
Ordered Mesoporous ◽  
Resonance Spin

Ordered mesoporous carbon (OMC) materials have received attention for use as supports in highly efficient catalytic systems because of their excellent properties. We used epoxy compound 2,3-epoxypropyl trimethylammonium chloride (EPTAC) to modify cobalt tetraaminophthalocyanine (CoTAPc) and obtained a novel catalyst (OMC-CoTAPc-EPTAC) based on OMC-bonded CoTAPc-EPTAC that could oxidize Acid Red 1 (AR1) dyes by hydrogen peroxide (H2O2) activation under neutral conditions. OMC enhanced the catalytic performance of OMC-CoTAPc-EPTAC, which resulted in the combined high catalytic activity and high stability. Because of its large surface area and tunable pore texture, OMC has high substrate accessibility, and the modification of the catalyst with EPTAC could promote adsorption of the target substrate into OMC, which achieved the aim of in situ catalytic oxidation with enrichment of the target substrate and improved the catalytic efficiency significantly. Electron paramagnetic resonance spin-trap experiments confirmed that the OMC-CoTAPc-EPTAC/H2O2system had a nonradical catalytic mechanism, and the high-valent cobalt-oxo intermediates and generated holes were speculated to act as dominant oxidation species for the catalytic degradation of AR1. These results demonstrated a new strategy for the elimination of low-concentration organic pollutants.

scholarly journals Facile One-Step Hydrothermal Fabrication of (Sr0.6Bi0.305)2Bi2O7/SnO2 Heterojunction with Excellent Photocatalytic Activity

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 321 ◽  
Author(s):  
Di Zhu ◽  
Xinling Wang ◽  
Huiting An ◽  
Yan Zhong ◽  
Dianhui Wang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Dominant Role ◽  
Light Response ◽  
Photocatalytic Efficiency ◽  
Response Range ◽  
Structure Morphology ◽  
Excellent Photocatalytic Activity ◽  
Pyrochlore Type ◽  
One Step

The pyrochlore-type (Sr0.6Bi0.305)2Bi2O7 (SBO), containing Bi3+ and Bi5+ mixed valent states, was recently found to be used as a new visible light responsive photocatalyst. Novel SBO/SnO2 heterostructured composites were synthesized through a facile one-step hydrothermal method. The phase structure, morphology, chemical composition, and optical properties of the obtained samples were characterized by XRD, SEM, TEM, XPS, and UV-vis DRS. Compared to pure SBO and SnO2, the synthesized SBO/SnO2 composites exhibited significantly enhanced photocatalytic efficiency. The results indicated that the photoinduced holes and superoxide radicals play a dominant role and are the main reactive species during the degradation of Methylene Blue (MB) solution under visible light irradiation. Heterojunctions, formed in samples, directly contribute to the improvement of photocatalytic efficiency of SBO/SnO2 composites, since it not only broadens the light response range, but also accelerates the separation of photogenerated carriers.

scholarly journals CeO2/CdS Heterojunctions Decorated Cotton Fabrics as Facile Recyclable Photocatalysts for Highly Efficient Visible Light Driven Degradation of Methylene Blue

2021 ◽  
Author(s):  
Rui Zou ◽  
Linhua Li ◽  
Lin Yang ◽  
jianwu lan ◽  
Hongyu Liu ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Cotton Fabric ◽  
Low Cost ◽  
Light Response ◽  
Cotton Fabrics ◽  
Degradation Efficiency ◽  
Cds Nanoparticles ◽  
Composite Photocatalysts ◽  
Visible Light Driven

Abstract In this work, visible light response CeO2/CdS decorated cotton fabrics as durable and facile recyclable composite photocatalysts were fabricated for photo-degradation of methylene blue (MB). First of all, amino-functionalized CeO2/CdS nanoparticles were synthesized through a fast, efficient and low-cost coprecipitation method. Subsequently, the as-prepared CeO2/CdS nanoparticles were immobilized on aldehyde-functionalized cotton fabric surfaces as composite photocatalysts via "amine-aldehyde" chemical reaction. The surface microstructure and chemical composition of the CeO2/CdS decorated cotton fabric (CeO2/CdS-CF) were characterized by SEM, FTIR and XPS, respectively. The results showed that CeO2/CdS nanoparticles were successfully anchored on the surface of cotton fabric, and distributed uniformly. As expected, the as-prepared CeO2/CdS-CF exhibited excellent photocatalytic activity, which can degrade MB within 90 min with a degradation efficiency of 93.8% under simulated sunlight irradiation, due to the CeO2/CdS heterostructure with the efficient photo-generated charge transfer and separation. In addition, the degradation efficiency remained above 90.3% after five successive degradation cycles, indicating that the obtained CeO2/CdS-CF possessed excellent stability and recyclability. This work opened up a facile preparation way for the fabrication of durable and recyclable composite photocatalysts, and has a promising application in treating dye contaminated wastewater.

Modification of BiOCl Nanosheets with Bi2O3 Nanoparticles by a Facile Two Step Method and the Enhanced Photocatalytic Performance of the Composites

2017 ◽  
Vol 46 ◽  
pp. 203-211 ◽  
Author(s):  
Zhan Kui Cui ◽  
Er Kang Hu ◽  
Sen Lin Li
Keyword(s):  
Reaction Rate ◽  
Photocatalytic Performance ◽  
Light Response ◽  
Step Method ◽  
Response Range ◽  
Composite Photocatalysts ◽  
Photocatalytic Activities ◽  
Carrier Separation ◽  
Improved Performance

Bi2O3/BiOCl composite photocatalysts were produced by a facile two step method, including ultrasonically modifying BiOCl nanosheets with Bi nanoparticles first and the subsequent in situ thermal oxidation process. The samples were characterized by XRD, SEM, UV-vis and photoluminescence techniques. The photocatalytic activities were evaluated by photodegrading Rhodamine B under Xe light irradiation. The abilities of generating hydroxyl radicals during photocatalysis were tested by fluorescence method. The results show that Bi2O3 NPs were randomly distributed on the surface of BiOCl nanosheets. The photocatalytic efficiency was enhanced after modification and the best photocatalytic activity was obtained when the mole ratio of Bi2O3 to BiOCl was 0.24. The corresponding photochemical reaction rate of Bi2O3/BiOCl was 7 times that of BiOCl nanosheets and 5 times that of Bi2O3 nanoparticles. The improved performance of the composites was considered to associate with the extended light response range and the promoted charge carrier separation.

scholarly journals Fe3O4@C Nanoparticles Synthesized by In Situ Solid-Phase Method for Removal of Methylene Blue

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 330
Author(s):  
Hengli Xiang ◽  
Genkuan Ren ◽  
Yanjun Zhong ◽  
Dehua Xu ◽  
Zhiye Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Solid Phase ◽  
Raw Materials ◽  
Phase Method ◽  
Maximum Adsorption Capacity ◽  
High Catalytic Activity ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
High Concentrations

Fe3O4@C nanoparticles were prepared by an in situ, solid-phase reaction, without any precursor, using FeSO4, FeS2, and PVP K30 as raw materials. The nanoparticles were utilized to decolorize high concentrations methylene blue (MB). The results indicated that the maximum adsorption capacity of the Fe3O4@C nanoparticles was 18.52 mg/g, and that the adsorption process was exothermic. Additionally, by employing H2O2 as the initiator of a Fenton-like reaction, the removal efficiency of 100 mg/L MB reached ~99% with Fe3O4@C nanoparticles, while that of MB was only ~34% using pure Fe3O4 nanoparticles. The mechanism of H2O2 activated on the Fe3O4@C nanoparticles and the possible degradation pathways of MB are discussed. The Fe3O4@C nanoparticles retained high catalytic activity after five usage cycles. This work describes a facile method for producing Fe3O4@C nanoparticles with excellent catalytic reactivity, and therefore, represents a promising approach for the industrial production of Fe3O4@C nanoparticles for the treatment of high concentrations of dyes in wastewater.

scholarly journals Real roles of perylene diimides for improving photocatalytic activity

RSC Advances ◽  
2020 ◽  
Vol 10 (39) ◽  
pp. 23024-23037 ◽  
Author(s):  
Fengxia Zhang ◽  
Wenjing Li ◽  
Tianyi Jiang ◽  
Xuemei Li ◽  
Yuanyuan Shao ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Hydrothermal Method ◽  
Perylene Diimides ◽  
Photodegradation Rate ◽  
Composite Photocatalysts ◽  
Visible Light Driven

Three novel visible-light-driven composite photocatalysts were synthesized by hydrothermal method. The effects of introducing PDIs with different structures into TiO2 were evaluated by assaying the photodegradation rate of methylene blue.

scholarly journals Application of BiOX Photocatalysts in Remediation of Persistent Organic Pollutants

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 604 ◽  
Author(s):  
Robert Arthur ◽  
John Ahern ◽  
Howard Patterson
Keyword(s):  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Radical Scavenging ◽  
Flow Chemistry ◽  
Active Species ◽  
Effective Strategies ◽  
Degradation Of Dyes ◽  
Bismuth Oxyhalides ◽  
Electron Holes

Bismuth oxyhalides have recently gained attention for their promise as photocatalysts. Due to their layered structure, these materials present fascinating and highly desirable physicochemical properties including visible light photocatalytic capability and improved charge separation. While bismuth oxyhalides have been rigorously evaluated for the photocatalytic degradation of dyes and many synthesis strategies have been employed to enhance this property, relatively little work has been done to test them against pharmaceuticals and pesticides. These persistent organic pollutants are identified as emerging concerns by the EPA and effective strategies must be developed to combat them. Here, we review recent work directed at characterizing the nature of the interactions between bismuth oxyhalides and persistent organic pollutants using techniques including LC-MS/MS for the determination of photocatalytic degradation intermediates and radical scavenging to determine active species during photocatalytic degradation. The reported investigations indicate that the high activity of bismuth oxyhalides for the breakdown of persistent organic pollutants from water can be largely attributed to the strong oxidizing power of electron holes in the valence band. Unlike conventional catalysts like TiO2, these catalysts can also function in ambient solar conditions. This suggests a much wider potential use for these materials as green catalysts for industrial photocatalytic transformation, particularly in flow chemistry applications.

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