Photocatalytic Degradation Of MO Research Articles

Shape-dependent synthesis and photocatalytic degradation by Cu2O nanocrystals: Kinetics and photocatalytic mechanism

In this study, Cu2O crystals with different morphologies were synthesized to investigate the effect of exposed crystalline facets on photocatalytic degradation efficiency. By adjusting the addition amount of PVP, different morphologies of Cu2O crystals were obtained, such as cubic, decahedral, octahedral, etc. XRD, SEM, and TEM characterizations were used to observe the properties of the synthesized Cu2O in terms of morphology, size, and lattice structure. The results showed that the octahedral cuprous oxide had the strongest photocatalytic degradation effect (78.3%). The study also explored the connection between different crystalline facets and MO microstructure, and the effect of crystalline facet selectivity on the pre-absorption and photocatalytic degradation of MO. Density Functional Theory (DFT) calculations were used to investigate the connection between the energy level structure of different crystalline facets of Cu2O and its photocatalytic activity. Finally, based on the experimental analysis and theoretical calculation, a new charge separation model on crystalline surface was proposed.

RETRACTED: Ionic liquid-assisted preparation of g-C3N4/RGO co-intercalated CuBi2O4 hierarchical nanoflower and enhancement of the photocatalytic activity

A new p-n type CBO/CN/RGO ternary heterojunction photocatalyst combining three-dimensional multi-stage rosette CuBi2O4 and two-dimensional g-C3N4 and RGO flakes was successfully prepared by ionic liquid-assisted hydrothermal method. The successful construction of p-n heterojunctions of CBO/CN/RGO composites was verified by means of UV–vis diffuse reflection, Mott Schottky curves and TEM, and construction the heterojunctions significantly improved that of the transfer and transport speed of photogenerated carriers. The photocatalytic degradation of MO by CBO/CN/RGO-6% reached 91.83% within 150 min, while the kinetic constants of degradation k were 9.7 and 7.9 times greater than those of single-phase CBO and g-C3N4, respectively. Three cycles of experiments demonstrated that the degradation efficiency of CBO/CN/RGO-6% composites remained above 88% for RhB, which fully proved that the CBO/CN/RGO-6% composites possessed good chemical stability. Based on its excellent photocatalytic performance and good stability, CBO/CN/RGO-6% is expected to be the preferred material for environmental wastewater treatment.

Biosynthesis of ZnO nanoparticles using Hagenia abyssinica leaf extracts; their photocatalytic and antibacterial activities

ABSTRACT This study investigates the green synthesis of ZnO NPs using an aqueous solution of hagenia abyssinica leaf extract, which acts as a reduction of zinc acetate dihydrate as a reducing agent and stabilizing agent. The synthesized ZnO NPs were characterized by various techniques such as XRD, SEM, FTIR, and UV–Vis spectroscopy. The XRD pattern confirmed that the hexagonal crystalline phase structure and average crystal size of the synthesized nanoparticle was 27.833 nm. Several functional groups were detected using the Fourier transform infrared (FTIR) method. Within 120 minutes of sunlight irradiation, 83.17% photocatalytic degradation of MO was recorded, with an initial concentration of 15 ppm and a catalyst dosage of 40 mg. The present study shows a novel, eco-friendly method to synthesize zinc oxide nanoparticles that have potential applications in water treatment and dye degradation. The disc diffusion method was used to determine antibacterial activity against gram-positive (S. aureus and S. epidermidis) and gram-negative (E. coli and K. pneumoniae) bacterial strains. The biosynthesized ZnO nanoparticles were highly effective against S. epidermidis with inhibition zones of 21 ± 1.0 mm at 30 mg/mL and less effective against E. coli with inhibition zones of 16 ± 1.0 mm at 10 mg/mL.

Biosynthesis Microwave-Assisted of Zinc Oxide Nanoparticles with Ziziphus jujuba Leaves Extract: Characterization and Photocatalytic Application

The present work is intended to biosynthesize zinc oxide nanoparticles (ZnO NPs) via facile and modern route using aqueous Ziziphus jujuba leaves extract assisted by microwave and explore their photocatalytic degradation of methyl orange anionic dye and methylene blue cationic dye under solar irradiation. The biosynthesized microwave assisted ZnO NPs were characterized and the results showed that ZnO NPs contain hexagonal wurtzite and characterized with a well-defined spherical-like shape with an outstanding band gap (2.70 eV), average particle size of 25 nm and specific surface area of 11.4 m2/g. The photocatalytic degradation of the MO and MB dyes by biosynthesized ZnO NPs under solar irradiation was studied and the results revealed the selective nature of the ZnO NPs for the adsorption and further photocatalytic degradation of the MO dye compared to the MB dye. In addition, the photocatalytic degradation of MO and MB dyes by the ZnO NPs under solar radiation was fitted by the first-order kinetics. Moreover, the photodegradation mechanism proposed that superoxide ions and hydroxyl radicals are the main reactive species.

Preparation of spherical α-Fe2O3 nanoparticles and its photocatalytic degradation of MO and MB

Preparation of spherical α-Fe2O3 nanoparticles and its photocatalytic degradation of MO and MB

Synergistic Effect of “Science” and “Education” to Cultivate Outstanding Innovative Talents under Background of National First-Class Undergraduate Majors Construction: Taking the Photocatalytic Degradation of MO with BiOI as an Example

Synergistic Effect of “Science” and “Education” to Cultivate Outstanding Innovative Talents under Background of National First-Class Undergraduate Majors Construction: Taking the Photocatalytic Degradation of MO with BiOI as an Example

Catalytic Activity and Kinetic Studies of Core@Shell Nanostructure NiFe2O4@TiO2 for Photocatalytic Degradation of Methyl Orange Dye

Current research focuses on synthesis and characterization of magnetically separable core@shell (NiFe2O4@TiO2) nanostructured photocatalyst with different weight percent (10, 20, 30, and 40) TiO2 using simple wet chemical techniques. Magnetic core with TiO2 shell was synthesized by the hydrolysis of TTIP precursor with NiFe2O4 nanoparticles. NiFe2O4 nanoparticles were synthesized by the sol-gel auto combustion method. The synthesized nanostructures were characterized for structural, morphological and magnetic behavior using XRD, TEM, SEM and VSM while the surface area was calculated using Brunauer-Emmett-Teller analyzer. Pure nickel ferrite was indexed as spinel FCC crystal structure while anatase titania was confirmed from the characteristic peaks in the indexed XRD patterns. SEM images show the uniform particle size and spherical morphology with average size of 18.85 nmand#177;2nm. The Surface area of prepared core@shell nanostructures was found as 258 m2/g for 10 wt. % TiO2 photocatalyst. A decrease in surface area has been observed with the increase in TiO2 percentage. The photo-catalytic degradation of MO was studied using UV-Visible spectroscopy under NiFe2O4-TiO2 catalyst. UV-spectra revealed degradation of methyl orange by the decrease in the characteristic peak at 460 nm. Kinetics of degradation reaction were studied by the integral method of analysis using UV absorbance data at 460 nm. The photo-catalytic activity of as synthesized catalyst was enhanced many folds as compared to the pure nickel ferrite. M-H curves obtained from VSM revealed a decrease in the magnetization of nickel ferrite with a coating of non-magnetic TiO2.

Catalytic Activity and Kinetic Studies of Core@Shell Nanostructure NiFe2O4@TiO2 for Photocatalytic Degradation of Methyl Orange Dye

Current research focuses on synthesis and characterization of magnetically separable core@shell (NiFe2O4@TiO2) nanostructured photocatalyst with different weight percent (10, 20, 30, and 40) TiO2 using simple wet chemical techniques. Magnetic core with TiO2 shell was synthesized by the hydrolysis of TTIP precursor with NiFe2O4 nanoparticles. NiFe2O4 nanoparticles were synthesized by the sol-gel auto combustion method. The synthesized nanostructures were characterized for structural, morphological and magnetic behavior using XRD, TEM, SEM and VSM while the surface area was calculated using Brunauer-Emmett-Teller analyzer. Pure nickel ferrite was indexed as spinel FCC crystal structure while anatase titania was confirmed from the characteristic peaks in the indexed XRD patterns. SEM images show the uniform particle size and spherical morphology with average size of 18.85 nmand#177;2nm. The Surface area of prepared core@shell nanostructures was found as 258 m2/g for 10 wt. % TiO2 photocatalyst. A decrease in surface area has been observed with the increase in TiO2 percentage. The photo-catalytic degradation of MO was studied using UV-Visible spectroscopy under NiFe2O4-TiO2 catalyst. UV-spectra revealed degradation of methyl orange by the decrease in the characteristic peak at 460 nm. Kinetics of degradation reaction were studied by the integral method of analysis using UV absorbance data at 460 nm. The photo-catalytic activity of as synthesized catalyst was enhanced many folds as compared to the pure nickel ferrite. M-H curves obtained from VSM revealed a decrease in the magnetization of nickel ferrite with a coating of non-magnetic TiO2.

Facile synthesis of hierarchical ZnIn2S4/CdIn2S4 microspheres with enhanced visible light driven photocatalytic activity

Hierarchical ZnIn2S4/CdIn2S4 microspheres have been synthesized by a facile chemical co-precipitation method at low temperature. The obtained samples were characterized by XRD, SEM, XPS, and UV–vis DRS. The XRD patterns of ZnIn2S4/CdIn2S4 showed the distinctive peaks of both ZnIn2S4 and CdIn2S4. The obtained ZnIn2S4 microspheres were composed of numerous large nanoplates, while CdIn2S4 microspheres possessed a relatively smooth surface. As for ZnIn2S4/CdIn2S4 composites, it was observed that partial of the ZnIn2S4 nanoplates were grown on the surface of CdIn2S4 microspheres. The absorption edge of ZnIn2S4 move toward longer wavelengths with the increment of CdIn2S4 component. In the photocatalytic degradation of MO, the ZnIn2S4/CdIn2S4 (mole ratio=1:3) photocatalyst exhibited the best activity compared with pure ZnIn2S4 and CdIn2S4. The degradation ratio of MO (10ppm) was about 99.7% after 90min of reaction, while RhB (4×10−5M) could be completely degraded within 70min over ZnIn2S4/CdIn2S4. The activity enhancement can be ascribed to the improvement of visible light adsorption and separation efficiency enhancement of photo-generated carriers. Controlled experiments proved that active species of O2−, OH, and h+ were produced in the degradation system, which played the major role in the degradation process.

Sol–gel microwave assisted synthesis of Sm-doped TiO2 nanoparticles and their photocatalytic activity for the degradation of Methyl Orange under sunlight

Samarium doped TiO2 nanoparticles were prepared by microwave assisted sol–gel method. The synthesized nanomaterials were characterized by various techniques such as XRD, SEM, EDS, TEM, UV-DRS, UV–Vis. spectrophotometer. XRD pattern of nanomaterials indicates Sm doped TiO2 primarily consist of anatase phase with spherical shape. It is also found that the crystallite size of Sm doped TiO2 is much smaller than undoped TiO2 (10 nm). The photocatalytic activity of TiO2 and Sm doped TiO2 were also investigated on the photocatalytic degradation of MO under UV and solar light irradiation. Sm doped TiO2 shows 96 and 84 % degradation of MO in 120 min under UV light and sunlight respectively. This indicates about 10 % increment in the photocatalytic activity. The effect of operational parameters such as catalyst loading, pH of dye and irradiation sources on photodegradation of MO was also investigated.

Pt-porous ZnO nanoribbon hybrid materials with enhanced catalytic performances

With the help of bio-molecule l-lysine, a seeded growth method has been developed and Pt–ZnO porous nanoribbons have been successfully obtained. For the catalytic applications of CO oxidation and the photocatalytic degradation of MO, the hybrid nanomaterial exhibits remarkably enhanced catalytic properties.

Controllable one-step synthesis of ZnO nanostructures using molybdophosphoric acid

AbstractZnO nanostructures were synthesised in a hydrothermal reaction of zinc acetate in the presence of molybdophosphoric acid (H3[PMo12O40]) as well as its vanadium-substituted acid (H4[PMo11VO40]) at various times, temperatures, and concentrations. The ZnO nanostructures were characterised by X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The results demonstrated that the synthesised products are crystalline with a zincite hexagonal phase. Various ZnO nanostructures, such as nanoparticles, microrods, and nanosheets, were produced by changing the experimental conditions. The photocatalytic degradation of methyl orange was also investigated using the ZnO nanoparticles thus prepared. These particles exhibited high performance in the photocatalytic degradation of MO and almost 100 % decolourisation occurred within only 20 min.

Green synthesis of Au/TiO2 for effective dye degradation in aqueous system

Nanocomposites of Au/TiO2 were prepared by green synthesis method using the aqueous extract of Cinnamomum tamala leaves as the reductant. The structural and morphological properties of the nanocomposites were studied by X-ray diffraction, UV–visible diffuse reflectance, FT-IR and transmission electron microscope. XRD and TEM analysis exhibits the formation of well dispersed gold nanoparticles on the surface of titania. The photocatalytic activity of the catalysts prepared by green method was evaluated for the degradation of methyl orange as a model reaction. It was found that the catalysts modified with 2wt% gold (2Au/TiO2-9-2) exhibits 2.5 times higher degradation activity towards methyl orange dye compared to Degussa P-25 TiO2 under solar light irradiation. Effect of parameters such as pH and plant extract concentration has been evaluated on the morphology of gold nanoparticles and photocatalytic degradation of MO. The dye degradation rate followed first order kinetics.

Effect of Additives on Photocatalysis of Cr(VI)-Methyl Orange

Photocatalysis technology is an efficient chemical method for wastewater treatment containing organic and inorganic pollutants. Adding additives may affect the photocatalytic process. The photocatalytic processes of 50 mL mixed solution, 40 mg/L MO-20 mg/L Cr(VI), were proceeded under λ≥420, pH=1. When adding organics (such as isopropanol, methyl alcohol, alcohol, acetone), photocatalytic efficiency of MO was restrained, and that of Cr(VI) was promoted. Adding materials such as formaldehyde with both oxidizing and reducing effects could promote photocatalytic efficiency of MO and Cr(VI) at the same time. When H2O2 added into the composite system, the influence of photocatalysis is relatively complicated. Through controlled experiment, the results show that H2O2-Cr(VI) could form Fenton reagent and speed up the photocatalytic degradation of MO. When inorganic cation (such as Na+, Cu2+, Fe3+) and inorganic anion (such as Cl-, NO2-, S2O32-) added into the composite system, there is no obvious rule. Experimental study show that adding cationics make the photocatalytic reduction of Cr(VI) inhibited, and adding anion which has the reducibility could promote the photocatalytic efficiency of Cr(VI). Since NO2- and S2O32- have simple chemical reactions with Cr(VI), photocatalytic degradation of MO under visible light also could proceed successfully.

An Active La-Doped Cu<sub>11</sub>O<sub>2</sub> (VO<sub>4</sub>)<sub>6</sub> Photocatalyst Prepared by Sol-Gel Method

A La-doped Cu11O2 (VO4)6 photocatalyst with optimum La/Cu molar ratio of 4% was prepared by sol-gel method. XRD,SEM and EDX have been employed to characterize the as-synthesized materials. During liquid phase photocatalytic degradation of MO under the UV-light, the as-prepared La/ Cu11O2 (VO4)6 exhibits higher activity than the pure Cu11O2 (VO4)6. It found that the La/ Cu11O2 (VO4)6 prepared with the La/Cu molar ratio of 4% and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 92.45% or so in 60min under 20W UV light.

Nitrogen-doped TiO2 nanotube array films with enhanced photocatalytic activity under various light sources

Highly ordered nitrogen-doped titanium dioxide (N-doped TiO2) nanotube array films with enhanced photocatalytic activity were fabricated by electrochemical anodization, followed by a wet immersion and annealing post-treatment. The morphology, structure and compostition of the N-doped TiO2 nanotube array films were investigated by FESEM, XPS, UV-vis and XRD. The effect of annealing temperature on the morphology, structures, photoelectrochemical property and photo-absorption of the N-doped TiO2 nanotube array films was investigated. Liquid chromatography and mass spectrometry were applied to the analysis of the intermediates coming from the photocatalytic degradation of MO. The experimental results showed that there were four primary intermediates existing in the photocatalytic reaction. Compared with the pure TiO2 nanotube array film, the N-doped TiO2 nanotubes exhibited higher photocatalytic activity in degradating methyl orange into non-toxic inorganic products under both UV and simulated sunlight irradiation.

The photocatalytic activity and kinetics of the degradation of an anionic azo-dye in a UV irradiated porous titania foam

A porous organic–inorganic hybrid titania foam, prepared from a long chain organic surfactant, hexadecylamine (HDA) and a semiconductor powder was characterized by microscopic and spectroscopic techniques and photocatalytically evaluated for the solution phase decomposition of methyl orange under alkaline conditions. Kinetic data obtained indicate conformity with Langmuir–Hinshelwood kinetic model at the initial stages of the degradation reaction. An attempt was made to study the effect of experimental parameters including catalyst loading and dye concentration on photocatalytic degradation of MO. Results indicate that the rate of reaction is governed by adsorption of azo-dye into the surface of the photocatalyst materials and suggests an optimum catalyst load and dye concentration for the degradation reaction. Light absorption and scattering within the substrate reaction zone and arising from differences in optical properties of catalyst material, made it impossible to interpret entire kinetic data on the basis of a simple Langmuir–Hinshelwood kinetics. However, kinetic data obtained at the initial stages of the reaction suggest conformity with first-order kinetics. The foam promises to be a versatile material in that it can be used for the treatment of low concentrations of pollutants of biological, organic and inorganic origins in water and air.