Photocatalyst For Degradation Research Articles

Treatment and ecotoxicity assessment of wastewater containing organic pollutants using a new CoFe2O4/biochar photocatalyst composite

ABSTRACT This is the first record on literature to use biochar as support for CoFe2O4 to applicate and evaluate it as photocatalyst for degradation of organic pollutants. The support was verified by XRD, FT-IR, SEM, EDS and band gap. Composites CFO1BQ3, CFO1BQ1, and CFO3BQ1 showed 100% degradation in 60 min. This outstanding performance can be related to the drop in band gap energy and recombination rate of e¯/h + . The composites showed better efficiency when compared to pure CoFe2O4 (∼78%). This might be associate to the fact that biochar has a high concentration of phenolic, hydroxyl and carboxylic functional groups on its surface. In this reaction h+, O2 •-, and •OH were the reactive species involved in the degradation. The toxicity of ponceau was tested before and after the treatment, through biochemical biomarkers in Danio rerio fish. In general, the treatment proved to be efficient in reducing ponceau toxicity in D. rerio fish.

Narrowing Band Gap of Zno Codoping (Al+Mn) as a Photocatalyst Candidate for Degraded Textile Dye Wastewater

Photocatalyst degradation is one method to reduce industrial textile dye pollution in water. In this study, ZnO material has been synthesized by codoping Al and Mn by chemical coprecipitation method to determine the structural properties and optical properties of the material. From this research, it was found that the structure of ZnO after codoping Al and Mn did not change the hexagonal wurtzite phase but changes in other lattice parameters. The addition of Mn and Al codoping is reported to affect the intensity of XRD peaks, especially on the 101 lattice. The higher the scattering peak, the more angular the shift, indicating the magnitude of oxygen vacancies. The reflectance confirms this result that increasing Mn concentration decreases the energy gap to 3.258 eV. From these structural properties and energy gap values, ZnO codoping Al and Mn materials can be included in candidate materials that can be used as photodegradation agents for textile dyes.

Copper doping induced band structure and morphology transformation in CaTiO3 for textile dye photodegradation applications

Semiconductor metal oxides with a wide bandgap like CaTiO3 can be exploited into an efficient visible light photocatalyst via cation doping. The type of dopant and the site of doping is known to greatly influence the photocatalytic activity of a material. Based on the intricacies of the density functional theory electronic structure study, we delve into the optimization of one-pot solvothermal synthesis to obtain Cu doped CaTiO3 nanocuboids. Doping of copper not only resulted in change in the electronic structure of the material but also led to change in the morphology. The uneven nanostep architecture resulted in increase in the surface area of the catalyst, which led to more active sites for the adsorption of the dyes and subsequent degradation. The reduced band gap and decreased recombination of charge carriers made the copper doped calcium titanate an efficient photocatalyst for degradation of both cationic (99.7% degradation of MV dye in 120 minutes) and anionic (99.8% degradation of RB in 45 minutes) dyes.

Green auto-combustion synthesis of SrNiO3/NiO/SrCO3 ferromagnetic-nanocomposites in the presence carbohydrate sugars and their application as photocatalyst for degradation of water-soluble organic-pollutants

This study utilized an environmentally-friendly method to synthesize SrNiO3/NiO/SrCO3 nanocomposites using glucose and lactose as fuels. A variety of fuel concentrations were investigated in order to determine their effects on SrNiO3/NiO/SrCO3 nanocomposites from both a pure and a morphological perspective. Various physiochemical techniques were employed to examine the crystal structure, morphology, optical, magnetic, and surface properties of the synthesized nanoparticles. These techniques included X-ray diffract, scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR), vibrating sample magnetometers, and Brunauer-Emmett-Tellers. The band gap of the as-synthesized nanoparticles was determined to be 2.5eV, suggesting that they are capable of acting as a photocatalyst under sunlight-like conditions. The photocatalytic activity of SrNiO3/NiO/SrCO3 nanocomposites was evaluated against Methyl orange (MO) and Methyl violet (MV), and the mechanism of the photocatalyst was investigated using EDTA, benzoic acid, and benzoquinone as scavengers. A comparison of photocatalytic activity in UV and sun-like light showed that maximum degradation (92%) and (84.8%) were related to degradation of MO (20 ppm) and MV in 60min, respectively. The results indicate that SrNiO3/NiO/SrCO3 nanocomposites synthesized using the auto combustion method may serve as a promising photocatalyst for the degradation of organic pollutants in the environment within a short period of time.

A highly effective PANI@(Ce-Er) dual doped ZnO (PCEZ) nanocomposite as UV-light driven photocatalyst for degradation of MB dye: synthesis and characterization

Utilizing ecologically friendly methods to address wastewater concerns is paramount. In this study, we developed novel PANI@(Ce-Er) dual-doped ZnO (PCEZ) nanocomposites using a wet impregnation approach assisted by ultrasound. These composites were thoroughly characterized using XRD, FESEM, EDX, UV-DRS, PL, and Impedance Analyzer techniques to assess their structural, optical, and electrical properties. Structural characterization was conducted to analyze the crystalline behavior and chemical composition of the synthesized samples. UV-DRS and PL spectroscopy were utilized to analyze their optical properties. Compared to PANI alone, the PCEZ heterojunction demonstrated enhanced photocatalytic stability and efficiency. Notably, in neutral media, the PCEZ heterojunction exhibited a significant photodegradation efficiency against methylene blue (MB), achieving approximately to 90.13% degradation. Morphology analysis of the synthesized samples and elemental composition was effectively performed using SEM images and EDX data. The UV-DRS investigation aimed to confirm the active contacts of dopant metals with polyaniline backbone chains and assess the energy band gap, which defines the absorption behavior of the photocatalyst. Kinetic studies of methylene blue degradation were characterized using the Pseudo First-Order relation, with the best adjusted R2 value of 0.9947 observed for 50% w/w (PANI@(Ce-Er)-ZnO). The produced PANI@(Ce-Er) dual-doped ZnO nanocomposites show promise as effective photocatalyst for the elimination of methylene blue in aqueous environments.

Synergistic effect in ZIF-67/MoS2 entrenched MWCNT photo (electro) catalyst for degradation of tetracycline and alternative to Pt counter electrode in dye-sensitized solar cells

Photocatalytic water purification is an effective environmental protection approach for removing hazardous chemicals in water, besides solar energy conversion is a trustworthy and sustainable choice for the future due to rising energy demands. The present research focus is on synthesis of Metal-Organic Framework (MOF) based composite, Zeolitic Imidazolate Framework-67/Molybdenum Disulfide (ZIF-67/MoS2) entrenched Multi-Walled Carbon Nanotubes (MWCNT) as a catalyst for photodegradation of tetracycline (TC), as well as substitute for Pt counter electrode in Dye-Sensitized Solar Cell (DSSC). The crystalline structure, optical response, shape, porosity, quantum states, and chemical configuration were determined using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-DRS), Photoluminescence spectroscopy (PL), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET), and X-ray Photoelectron Spectroscopy (XPS), respectively. The degradation efficiency of ZIF-67/MoS2/MWCNT catalyst under effect of operational parameters namely, photocatalyst dosage, solution pH, coexisting ions, TC concentrations and irradiation time were studied consecutively. ZIF-67/MoS2/MWCNT composite achieved 96.1 % degradation efficiency of TC under white light irradiation. Interestingly, when utilized as a counter electrode in DSSCs, this composite-based electrode delivered the highest Power Conversion Efficiency (PCE) of 3.86 % with a short-circuit current density (JSC) of 7.54 mA cm−2 and open-circuit voltage (VOC) of 0.79 V. The observed enhancement is attributed to lesser peak-to-peak separation (EPP), lower electron lifetime, lower charge transfer resistance (RCT) and higher exchange current density (J0). Based on these findings, ZIF-67 inclusion in MoS2/MWCNT composite is not only an effective catalyst for water treatment but also a good catalyst for I3− reduction in DSSCs.

Fabrication of tricobalt tetraoxide thinfilm photocatalyst from cobalt nitrate deposition by a novel spark method

Tricobalt tetraoxide (Co3O4) thinfilm was successfully deposited for the first time by a novel sparking method through a two-step process, which includes cobalt nitrate deposition and subsequent thermal treatment at 300 °C. The formation mechanism of Co3O4 deposition by sparking process from highly pure cobalt wire is elucidated in detail. Deposited Co3O4 thinfilms under different spark repetition rates were intensely characterized and employed as an effective photocatalyst for degradation of organic dye. Notably, the maximum degradation of organic dye was observed for the catalytic thinfilm deposited at low repetition rate owing to its low band gap and porous morphology with smaller size grains, which may lead to the contribution of more charge carriers in the photocatalytic reaction.

Photocatalytic degradation of antibiotics by N-doped carbon nanoflakes-nickel ferrite composite derived from algal biomass

This work reports the synthesis of nickel ferrite (NiFe) nanoparticles, N-doped mesoporous carbon nanoflakes (NCF) and novel nickel ferrite-carbon nanoflakes (NiFe@NCF) nanocomposite using solvothermal method. NCF was derived from a cyanobacterial consortium consisting of Anabaena, Lyngbya and Weistiellopsis, rich in carbon and nitrogen. The synthesized nanoparticles were used as heterogeneous photocatalyst for degradation of two harmful water pollutants, ciprofloxacin (CIP) and levofloxacin (LEV). 99.91% LEV and 98.86% CIP were degraded within 50 and 70 min of visible light irradiation using NiFe@NCF following pseudo first order kinetics. This improved efficiency of the nanocomposite may be attributed to its higher surface area, reduction of band gap (from 2.42 to 2.19 eV), more active sites as well as charge carrier mobility with decreasing agglomeration tendency of the magnetic nickel nanoparticles upon being embedded on NCF. N-doping improves light harvesting property, retards charge recombination and extends as well as delocalises ᴨ-conjugated system resulting in enhanced photocatalytic activity. The scavenging experiments and EPR analysis reveal that O2−• and •OH are the main active species taking part in the degradation process. The material performs well within a wide range of pH and can be effectively used up to 5 repetitive cycles. A feasible photocatalytic degradation mechanism of the antibiotics against NiFe@NCF nanocomposite is also put forwarded along with their possible degradation pathways from LCMS studies.

Synthesis of g-C3N4 decorated with ZIF-8 and CuFe2O4 as a highly efficient and magnetically separable photocatalyst for degradation of tetracycline

In this study, for the first time a magnetically recoverable zeolitic imidazolate framework-8 (ZIF-8) / graphite carbon nitride (g-C3N4)/ cooper ferrite (CuFe2O4) nanocomposite was prepared through a fast and simple wet impregnation procedure. The magnetic behavior of the ZIF-8/g-C3N4/CuFe2O4 heterostructure was used for the easy recovery of the nanocomposite by an external magnet. After studying the structural, crystallinity, magnetic, and photophysical properties of the as-syntesized sample, its application was investigated for the enhanced photodegradation of tetracycline under visible light illumination. The band gap energies for ZIF-8, g-C3N4, and CuFe2O4 were obtained 5.1 eV, 2.8 eV, and 1.3 eV, respectively. After combination of ZIF-8, g-C3N4, and CuFe2O4, the band gap energy was obtained to 2.4 eV, which indicate the improvement of photocatalytic activity of ZIF-8/g-C3N4/CuFe2O4 nanocomposite. Among the as-synthesized photocatalyst samples, the ZIF-8/g-C3N4/CuFe2O4 showed an excellent photocatalytic activity (99.15 %) for degradation of tetracycline within 65 min irradiation of visible light, solution pH of 5 and photocatalyst dosage of 0.75 g/L. The rate constant of the ZIF-8/g-C3N4/CuFe2O4 is almost 13.1, 9.9, and 15.6 times higher than that of ZIF-8, g-C3N4, and CuFe2O4, respectively. The ZIF-8/g-C3N4/CuFe2O4 heterojunction showed the effective degradation activity for four consecutive cycles, which exhibited its excellent reusability and stability. Moreover, the free radical quenching tests confirmed that holes, and hydroxyl radicals were the main reaction species for degradation of tetracycline. Altogether the preparation of novel ZIF-8/g-C3N4/CuFe2O4 provides an promise avenue for the development of high potential magtenticaly photocatalytic systems for sustainable tetracycline production with remarkable efficiencies.

Synthesis and Characterization of C/ZnO–NiO Nanoflower Composite as an Efficacious Photocatalyst for Degradation of Reactive Red 120 Dye Under Visible Light

Synthesis and Characterization of C/ZnO–NiO Nanoflower Composite as an Efficacious Photocatalyst for Degradation of Reactive Red 120 Dye Under Visible Light

Thioxanthone Functionalized NanoTiO2 Composites as Photocatalyst for Degradation of Organic Dyes.

Titanium dioxide (TiO2) photocatalytic technology has the advantages of high catalytic activity, high chemical stability, nontoxicity, and low cost. Therefore, it finds widespread applications in the degradation of organic pollutants in water, antibacterial, environmental purification, and other fields. In this study, we have obtained a photocatalyst by modifying nanoTiO2 with the photosensitizer thioxanthone. The light-harvesting units of thioxanthone and nanoTiO2 can work synergistically to capture light energy. As a heterogeneous photocatalytic material, it can efficiently degrade organic dyes such as Rhodamine B, methyl blue and methyl orange. Specifically, the degradation rate of 0.1 mmol/L Rhodamine B can reach 97% after 35 min of irradiation, and methyl blue and methyl orange can also reach 98 and 56%, respectively.

Facet-Engineered Cu2O Microparticles on Graphitic Carbon Nitride Nanosheets as Z-Scheme Heterojunction Photocatalysts for Degradation of Tetracycline

Facet-Engineered Cu₂O Microparticles on Graphitic Carbon Nitride Nanosheets as Z-Scheme Heterojunction Photocatalysts for Degradation of Tetracycline

Visible light-driven removal of Rhodamine B using indium-doped zinc oxide prepared by sol–gel method

Industrial dye contamination in wastewater poses significant environmental challenges, necessitating the development of efficient photocatalysts for degradation. In this work, we investigate the In doping effect in the photocatalytic activity of zinc oxide (ZnO) nanoparticles for effective RhB degradation. Indium-doped ZnO nanoparticles were synthesized via sol–gel method and x-ray diffraction (XRD) analysis revealed a wurtzite hexagonal structure, with the crystallite size being varying from 65 nm to 53 nm with the introduction of In content. XPS measurements on the 3% In-doped ZnO sample revealed distinct core level spectra for In 3d, Zn 2p, and O 1s regions, confirming the presence of indium, zinc, and oxygen. Brunauer–Emmett–Teller (BET) analysis revealed increased surface area and pore size, with specific surface areas escalating from 0.9 m²/g for pure ZnO to 10.1 m²/g for 3% indium-doped ZnO. Photocatalytic experiments exhibited significant RhB degradation, with degradation efficiencies reaching 93% for 3% indium-doped ZnO under visible light irradiation due to the effect of the presence of In, which causing light absorption enhancement, narrow the band gap and improve charge carrier separation. These findings underscore the potential of indium-doped ZnO nanoparticles as efficient and sustainable photocatalysts for wastewater treatment, offering a promising avenue to address environmental challenges associated with industrial dye-contaminated effluents.Graphical

GO/Bi2O2CO3/NiWO4 with Z-scheme heterojunction: Efficiently enhanced degradation of organic pollutants under visible light and DFT studies

A ternary composite of GO/Bi2O2CO3/NiWO4 (GBCNWO) was prepared via an in-situ of Bi2O2CO3 onto the surface of NiWO4 and Bi2O2CO3/ NiWO4 being warped by GO, which was thereafter untilled as catalyst in photodegradation of organic pollutants. The microstructure, and optical properties of all the prepared samples were characterized using various techniques such as XRD, FT-IR, SEM, TEM, TG-DTG, XPS, UV-Vis, ESR, and N2-adsorption. Amongst the studied samples, GBCNWO possessed the largest specific surface area, which would efficiently afford much more spaces for the exposing of active sites. Results of UV–vis and XPS suggested that GBCNWO was more efficient for the adsorption and conversion of visible light, and photocurrent conduction through graphite carbon ring could lessen the recombination rate of photoelectrons and holes. Also, the minor arc radius of GBCNWO unveiled its lowest photoresistors among the composites, indicating that the GBCNWO structured with GO, Bi2O2CO3 and NiWO4 has synergistic catalysis in the photodegradation. Importantly, 95.15 % of degradation rate was observed under the optimized conditions (pH=7, catalyst weight of 30 mg, 40 mg/L of MB, 25 °C). Additionally, the degradation rate of various substrates followed the order: MB (99.34 %) > ciprofloxacin (97.28 %) > RHB (97.01 %) > indole (27.47 %) > phenol (9.47 %). The quenching experiment and ESR test suggested that three kinds of active species (•OH, •O2− and h+) can be photogenerated during visible light radiation. Among them, •O2− was confirmed as the key species during the photocatalytic process, which could be adduced that the existence of oxygen vacancies made the receiving photoelectrons to reduce O2, forming the superoxide radical. Finally, a Z-scheme mechanism about the production of active radicals was proposed, which was also validated by DFT calculations.

A novel PANI@Er-doped ZnO (PEZ) MOFs: Synthesis, Characterization and highly efficient photocatalyst for degradation of Methylene Blue

A novel PANI@Er-doped ZnO (PEZ) MOFs: Synthesis, Characterization and highly efficient photocatalyst for degradation of Methylene Blue

Visible light responsive SiO2/g-C3N4/BiOBr/Bi heterojunction photocatalyst for degradation of rhodamine B

For the purpose of alleviating the negative influence of rhodamine B (RhB) abuse on the environment, it is imperative to design a green and efficient photocatalyst for tackling organic dye-contaminated wastewater. Herein, a novel SiO2/g-C3N4/BiOBr/Bi (denoted as Si/CN/BiOB/Bi) photocatalyst with enhanced photodegradation activity has been successfully created. The influence of variable parameters including Bi doping amount, initial concentration of RhB, photocatalyst dosage, and reaction temperature on the photocatalytic performance of Si/CN/BiOB/Bi under visible light illumination are analyzed in detail. Results indicated that the degradation rate constant of RhB over Si/CN/BiOB/Bi-0.5 is 25.1, 18.1, and 2.2 times higher than that of CN, Si/CN, and Si/CN/BiOB, respectively. The Si/CN/BiOB/Bi-0.5 photocatalyst displayed high photocatalytic performance after 5 recycled runs. The improved photocatalytic performance can be attributed to the novel morphology as well as the excellent synergetic effects of Si/CN, BiOBr, and Bi, which enables the catalysts to accelerate the separation of photogenerated carriers. In brief, a new Si/CN/BiOB/Bi photocatalyst has a great application perspective for the purification of RhB wastewater.

Biomass guided the formation of spherical catalysts for efficient photodegradation of tetracycline hydrochloride

Developing and evaluating advanced antibiotic degradation photocatalysts remains challenging owing to the lack of rational structural designs and molecular oxygen activation. In this study, a nanofluoral-biochar-modified bismuth vanadate (m-BiVO4) material with a specific structure was prepared via surface-assisted polymerization. The results show that the yeast-derived carbon material significantly broadened the capture range of n–p* visible light and improved the electron delocalization and carrier separation rates. Under visible light irradiation, m-BiVO4 exhibited a high photocatalytic degradation rate, and the degradation rate of 10 mg/L tetracycline (TC) reached 89.9 % within 180 min, almost three times that of the control group. An EPR test and free radical capture experiment showed that ·OH and ·O2– were the main active substances in the TC degradation process. Cyclic experiments also showed that the material had great stability and potential for reuse. The intermediate in the degradation pathway was identified using liquid chromatography-tandem mass spectrometry, the degradation pathway of TC in the composite system was predicted, and a corresponding degradation pathway was proposed. In this study, the synergistic effect of morphology adjustment and component cutting was realized using biomass templates, providing a new method for designing photocatalysts with specific structures.

Novel bilayer 2D V2O5 as a potential catalyst for fast photodegradation of organic dyes

Two-dimensional (2D) materials have recently drawn interest in various applications due to their superior electronic properties, high specific surface area, and surface activity. However, studies on the catalytic properties of the 2D counterpart of V2O5 are scarce. In the present study, the catalytic properties of 2D V2O5 vis-à-vis bulk V2O5 for the degradation of methylene blue dye are discussed for the first time. The 2D V2O5 catalyst was synthesized using a modified chemical exfoliation technique. A massive increase in the electrochemically active surface area of 2D V2O5 by one order of magnitude greater than that of bulk V2O5 was observed in this study. Simultaneously, ~ 7 times increase in the optical absorption coefficient of 2D V2O5 significantly increases the number of photogenerated electrons involved in the catalytic performance. In addition, the surface activity of the 2D V2O5 catalyst is enhanced by generating surface oxygen vacancy defects. In the current study, we have achieved ~ 99% degradation of 16 ppm dye using the 2D V2O5 nanosheet catalysts under UV light exposure with a remarkable degradation rate constant of 2.31 min−1, which is an increase of the order of 102 from previous studies using V2O5 nanostructures and nanocomposites as catalysts. Since the enhanced photocatalytic activity emerged from the surface and optical properties of the catalyst, the current study shows great promise for the future application of 2D V2O5 in photo- and electrocatalysis.

A new approach for synthesis of bismuth oxide derived photocatalyst for degradation of para nitrophenol

More focus has recently been placed on achieving the sustainable development objectives by 2030. As water is important and ha many purposes, it is important to have clean water. The inefficiency of different water treatment techniques restricts their widespread implementation. Furthermore, some of the procedures readily create secondary pollutants. As a result, it is critical to develop an effective and ecologically beneficial method of converting organic contaminants into non-toxic and harmless chemicals. A modified hydrothermal synthesis method was utilised for successfully producing Bi2O3 nanoparticles in this research. Fourier Transform Infrared (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy, and Energy Dispersive X-Ray were used to characterise and to find the structural, optical, morphological, and compositional aspects of the formed nanoparticles. Moreover, the formed particles were used to degrade the noxious Para-nitrophenol (PNP). PNP deterioration was performed under 3 different conditions: under halogen light, under sunlight and in the dark. The experiment showed that halogen irradiation showed better result. Due to PNP adsorption on Bi2O3, even without irradiation, a small degradation was detected but in just over an hour, under halogen light the catalyst destroyed 99.23 % of 4-nitrophenol. We also used natural lighting in our degradation studies. Natural daylight deterioration efficiency was 63.26 %. The nanoparticles that were formed turned out to be an excellent photocatalyst for the degradation of PNP in wastewater.

Synthesis of CBO (Co3O4-Bi2O3) Heterogeneous Photocatalyst for Degradation of Fipronil and Acetochlor Pesticides in Aqueous Medium

The excessive use of pesticides has led to the harmful contamination of water reservoirs. Visible-light-driven photocatalysis is one of the suitable methods for the removal of pesticides from water. Herein, the development of CBO (Co3O4-Bi2O3) as a heterogeneous catalyst for the visible light-assisted degradation of Fipronil and Acetochlor pesticides is reported. After synthesis via coprecipitation using cobalt (II) nitrate hexahydrate (Co(NO3)2·6H2O), bismuth (III) nitrate pentahydrate (Bi(NO3)3·5H2O) and sodium hydroxide (NaOH) as precursor materials, the prepared CBO was characterized using advanced techniques including XRD, EDS, TEM, SEM, FTIR, and surface area and pore size analysis. Then, it was employed as a photocatalyst for the degradation of Fipronil and Acetochlor pesticides under visible light irradiation. The complete removal of Fipronil and Acetochlor pesticides was observed over CBO photocatalyst using 50 mL (100 mg/L) of each pesticide separately within 120 min of reaction. The reaction kinetics was investigated using a non-linear method of analysis using the Solver add-in. The prepared CBO exhibited a 2.8-fold and 2-fold catalytic performance in the photodegradation of selected pesticides than Co3O4 and Bi2O3 did, respectively.