Degradation Rate Of MB Research Articles

Enhancement of catalytic performance by regulating the surface properties of Fe3O4 composites

Abstract As magnetic catalyst material, great studies have been made to improve the catalytic performance of Fe3O4 nanoparticles by changing the structure, but little attention has been paid to the relationship between the surface properties (the electronegativity, electron transport capacity) and the catalytic performance of Fe3O4 nanoparticles. Therefore, this work was devoted to the investigation of the relationship by loading Fe3O4 nanoparticles on graphene oxide(GO) grafted with N,N,N',N'-Tetrakis (2-hydroxyethy)ethylenediamine (THEED), which was denoted as TG@Fe3O4. N atoms in THEED and GO have strong electronegativity and electron mobility respectively, which greatly change the surface properties of the Fe3O4 composite. A large number of characterization methods have proved that the original structure of the produced Fe3O4 nanoparticles has not been changed, and the Zeta potential and cyclic voltammetry curves confirmed that the surface properties of Fe3O4 composite have been improved. In the Fenton degradation experiment of MB, TG@Fe3O4 can make the degradation rate of MB reach 100% in 8 min, which verified that the strong electronegativity and electron transport capacity were beneficial to the improvement of the catalytic performance of Fe3O4 composite.

New branch on old tree: Green-synthesized RGO/Fe3O4 composite as a photo-Fenton catalyst for rapid decomposition of methylene blue

Abstract We report herein the facile fabrication of reduced graphene oxide (RGO) loaded with Fe3O4 nanocomposites (consisting of gauze-like RGO nanosheets and Fe3O4 nanoparticles) through a simple, low-cost and environmental-friendly procedure that employs a brown alga (Sargassum thunbergii) as the solely reducing agent. The RGO/Fe3O4 nanocomposites could work as novel catalytic materials with magnetic and photo-Fenton catalytic properties. In the presence of Sargassum thunbergii, the spherical-shaped Fe3O4 nanoparticles with an average diameter of 7 nm have uniformly anchored on the RGO nanosheets. The material has displayed excellent performance in terms of dye degradation (methylene blue, MB), showing a 96% degradation rate of MB after 120 min irradiation under almost neutral pH environment, and room temperature conditions. After the reaction, the RGO/Fe3O4 nanocomposite could be easily separated and recycled due to its excellent ferromagnetism and superior stability. Our study provides a strong validation of RGO/Fe3O4 remarkable capacity toward visible-light-driven degradation of organic contaminates.

A Facile One‐Step Synthesis of Fe‐Doped g‐C3N4 Nanosheets and Their Improved Visible‐Light Photocatalytic Performance

AbstractA simple one‐step pyrolysis process (compared with the routine method of liquid exfoliation and impregnation) was designed to synthesize Fe‐doped graphitic carbon nitride (g‐C3N4) nanosheets with NH4Cl as dynamic gas template and FeCl3 as the Fe source. Results of XPS and DRS indicated that the Fe species might exist at the state of Fe3+ and form Fe−N bonds with N atoms, thereby expanding visible light absorption regions and reducing the band gap of g‐C3N4 nanosheets. Doping certain amounts of Fe could promote the exfoliation and further increase the specific surface area, while excessive Fe might break the sheet structure. The specific surface area of the optimized Fe‐doped g‐C3N4 nanosheets reached 236.52 m2 g−1, which was 2.5 times higher than that of g‐C3N4 nanosheets. Among various photocatalysts prepared, the sample (0.5 wt % FeCl3) exhibited maximum photocatalytic performance in degradation of Methylene Blue and water splitting under visible light irradiation. The degradation rate of MB was about 1.4 and 1.7 times higher than that of pure g‐C3N4 nanosheets and bulk g‐C3N4, respectively. The H2 production rate was 536 μmol h−1 g−1, which was 1.8 and 6 times higher than that of pure g‐C3N4 nanosheets and bulk g‐C3N4, separately.

Photocatalytic Properties of Graphene ZnNiAl-LDO Composites

In order to realize the heterogeneous phase of complex catalyst, nanoparticles immobilization and expansion application of graphene in the field of photocatalysis, through situ synthesis, graphene @ZnNiAl-LDO composite materials are produced, and with the use of XRD, FTIR, Raman, UV-vis and other characterization methods, this paper explores the differences of situ synthesis ZnNiAl-LDHs and pure ZnNiAl-LDHs structure and morphology in graphene oxide. The results show that the pure ZnNiAl-LDHs shape is micron particles in small disc. However, the situ growing ZnNiAl-LDHs in graphene oxide, its growing process is inhibited by the graphene and thus nano grain is formed. After calcination, the graphene @ZnNiAl-LDO composites were significantly improved compared with the original ZnNiAl-LDO samples in the whole UV-vis range. The absorption experiment showed that the @ZnNiAl-LDO had stronger adsorption performance of Cr(VI). Through the photocatalytic experiments, in MB and Cr (VI) coexisting solution, the visible light photocatalytic degradation rate of MB was significantly higher than that of pure MB solution, and the existence of Cr (VI) has a synergistic effect on graphene /ZnNiAl-LDO composite photocatalytic oxidation organic matter. As a result, it shows that graphene /ZnNiAl-LDO composites can be effectively used in the treatment of organic / heavy metal contaminated water.

Tailored synthesis of CuS nanodisks from a new macrocyclic precursor and their efficient catalytic properties on methylene blue dye degradation

In this study, CuS nanodisks have been synthesized from a tetraaza (N4) macrocyclic complex precursor by a facile wet chemical method. The crystallinity and morphology of the as-synthesized products were characterized by X-ray diffraction and transmission electron microscopy, which confirm a phase pure crystalline CuS nanostructures with ~15 to 20 nm in dimension with ~5 nm thickness. A possible formation mechanism and growth process of the CuS nanodisks are discussed using thiourea and tetraaza ligand as the sulfur donor and stabilizing agent, respectively. Cyclic N4 ligand also acts as a binding agent to template-guide the oriented growth of CuS nanodisks. The optimized geometry of ligands and complexes was calculated using B3YLP functional, which indicates that the HOMO in the complex located on metal center and N atoms are weakly bonded to the metal center. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than under dark in the presence of H2O2. The C t/C 0 plot as a function of time displays the higher MB degradation activity of CuS nanoparticles with H2O2. The recycle stability of CuS nanoparticles was even found to be >80 % after five cycles studied by repeating the MB degradation with same CuS nanoparticles sample. CuS nanostructures synthesized from a tetraaza macrocyclic complex precursor show the disk-like registry with average lateral dimension between 15 and 20 nm and thickness of 5 nm. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than in dark in the presence of H2O2.

A simple process to prepare few-layer g-C3N4 nanosheets with enhanced photocatalytic activities

Graphitic carbon nitride (g-C3N4) nanosheets with few-layer and single-layer structures were prepared by a simple chemical exfoliation method. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, UV–vis absorption spectroscopy and photoluminescence spectroscopy, respectively. The investigations indicated that the bulk g-C3N4 can be easily exfoliated into g-C3N4 nanosheets with few-layer structure under the assistance of HNO3. The specific surface area of few-layer g-C3N4 reached 179.5m2g−1, which was about 10.3 times higher than that of bulk g-C3N4 (17.4m2g−1). The absorption edge of few-layer g-C3N4 nanosheets showed a blue shift from 486nm to 458nm, corresponding to an increase in the band gap from 2.55eV to 2.70eV compared with that of bulk g-C3N4. In addition, the position of the emission peak of few-layer g-C3N4 was blue shifted from 461nm to 439nm. The photocatalytic performance of samples was evaluated by the degradation of methylene blue and the photocatalytic water splitting under visible light irradiation. The experimental results indicated that the degradation rate of MB on few-layer g-C3N4 nanosheets was about 1.3 times higher than that of bulk g-C3N4, the H2 production rate reached 110.68μmolg−1h−1 over g-C3N4 nanosheets, which was 1.22 times higher than that of bulk g-C3N4.

Three-dimensional flower-like hybrid BiOI–zeolite composites with highly efficient adsorption and visible light photocatalytic activity

Three-dimensional flower-like hybrid BiOI–zeolite composites were synthesized via a simple, facile and environmentally-benign hydrothermal method. And the synthetic mechanism of the flower-like BiOI–zeolite hierarchical structures was discussed. The as-obtained BiOI–zeolite samples exhibited excellent performance in the degradation of methylene blue solution under visible light irradiation. The influence of different Bi/I molar ratios and surfactants was studied. The degradation rate of MB by BiOI–zeolite composite photocatalysts can reach 94.8% under visible light irradiation for 10 min, when the Bi/I molar ratio is 1:1 and is surfactant free. This implies its huge application potential as photocatalysts in degradation of pollutants under visible light.

Heterostructured Er3+ doped BiVO4 with exceptional photocatalytic performance by cooperative electronic and luminescence sensitization mechanism

Er-BiVO4 has been synthesized by means of mw-assisted hydrothermal method having good photoactivity under sun-like excitation. It is stated that the precursor addition sequence plays a critical role which determine the further structural feature of BiVO4. From the structural and morphological characterization, it can be demonstrated that the presence of Er3+ would induce the stabilization of the tetragonal phase probably due to the formation of tetragonal-ErVO4 seeds previous to BiVO4 formation. The best photocatalytic performance is attained for the sample with 0.75at% Er3+ content. At this dopant loading a mixture of tetragonal and monoclinic phase (70% tetragonal) is obtained. The dramatic increase in the photocatalytic activity for 0.75at% Er-BiVO4 is related to the occurrence of such heterostructure. For this system, the MB degradation rate constant appears drastically higher as bare m-BiVO4. Furthermore, activities of photocatalysts for visible-light-driven O2 evolution have been evaluated, demonstrating that the photocatalytic activity of this Er-doped system (O2 evolution rate, 1014μmolg−1h−1) is 20 times as that of undoped m-BiVO4 (O2 evolution rate, 54μmolg−1h−1). From the obtained results, the cooperative conjunction of electronic and luminescence mechanism involved in the reaction is proposed to be the origin of the enhanced photocatalytic efficiencies of such systems.

Simultaneous Photocatalytic Removal of Cr(IV) Ions and Methylene Blue Using InVO<sub>4</sub>/TiO<sub>2</sub> Nanocomposites under the Sunlight Irradiation

InVO4/TiO2 nanocomposites were synthesized via a sol-gel process, and their microstructure and morphology were characterized by XRD and FESEM. XRD analysis indicated that incorporation of InVO4 with low content (In:Ti mole ratio of 1:200) could not change the crystallinity of anatase TiO2. The photocatalytic activity of anatase TiO2 increased for more than 2 folds by incorporating small amount of InVO4 into TiO2. The MB degradation rate kapp increased from 1.147×10-2 to 1.75×10-2 min-1 while the added Cr(IV) concentration was 5mg/L. The results indicated that simultaneous removal of aqueous Cr(IV) ions and organic compounds was feasible in the photocataltyic reactions under sunlight irradiation.

A preliminary research on V/N–TiO2 self-cleaning thin film by sol–gel method under the guidance of first principle method density functional theory (DFT)

A series of Ti1−xVxO2−yNy self-cleaning thin films, which can be activated driven by visible-light (VL), have been successfully immobilized on quartz glasses by sol–gel and dip-coating methods. The First Principle Method acts as guidance and reference for getting the critical (up-limitation) vanadium doping quantity in accordance with the binding energy change. Results of the band structure calculations and the doped density of states (DOS) reveal that localized impurity bands obviously existed in the band gap of TiO2 when the V doping quantity was ca.6at%, this film possesses the optimal visible light absorption by facilitating the transition of electron from the localized impurity band to the conduction band. Anatase crystalline phase was detected by the characterization of X-ray diffraction (XRD). TG/DTA, AFM, XPS, UV–vis, MB degradation and surface contact angle (CA) tests were also conducted for the film structural and optical properties. It is found that the mean square root (RMS) roughness of Ti0.94V0.06O1.94N0.06 (13.9nm) is ca.33 times than the others, the V, N mono-doping can increase visible light absorption (403nm), while V/N co-doping can greatly enhance absorption in lower frequency visible region (496nm). The MB degradation rate of Ti0.94V0.06O1.94N0.06 is 7.7×10−3molL−1min−1, while the rates of N-doped and pure TiO2 film were (1.94×10−3molL−1min−1) (0.8×10−3molL−1min−1), respectively. The CA on this kind of film can approach to ca. 5°. All these results indicated that the Ti1−xVxO1.94N0.06 does well in photocatalysis and photohydrophilicity within the region of visible light. It would be a promising practical self-cleaning function and application.

Facile Synthesis, Characterization and Photocatalytic Activity of MWCNT-Supported Metal Sulfide Composites under Visible Light Irradiation

This paper reported a simple deposition?precipitation method, introducing the metal (Ni, Ag and Sn) and Na2S· 5H2O to preparedispersion metal sulfide nanoparticles on the surface of the Multi-walled carbon nanotube for synthesis of CNT-MxSy (NiS2, Ag2S, SnS) composite photocatalysts. The characterization of the prepared CNT-MxSy (NiS2, Ag2S, SnS) composites was performed by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis and BET analysis. Furthermore, the MB degradation rate constant for CNT-SnS composite was 5.68 × 10?3 under visible light irradiation, which was much higher than the corresponding values for other samples. The detailed formation and photocatalytic mechanism are also provided here.

Spectroscopic and kinetic studies on the degradation of methylene blue using the supramolecular coordination polymer [(Ph3Sn)4Fe(CN)6] as catalyst

The structure of the supramolecular coordination polymer (SCP), [(Ph3Sn)4Fe(CN)6], 1, consists of octahedral [Fe(CN)6]4− building blocks which are connected by the TBPY-5 configured Ph3Sn(CN…)2 fragments creating 3D-network structure that contains terminal cyanide groups. The catalytic behavior of the SCP 1 was utilized for Fenton and photo-Fenton degradation of methylene blue dye (MB). The plot of kinetic degradation indicates pseudo first-order rate with respect to the MB dye concentration, Kobs.=0.071min−1. On the other hand, the observed rate constant of the photo catalytic degradation of MB equals to 1.45min−1 indicating that irradiation enhances, significantly, the rate of degradation of MB dye. Discoloration of the dye was obtained in less than 3h. Meanwhile, the conjugated structure and the phenyl rings of the MB molecule were destroyed or even broken down into small organic acids and inorganic ions, as indicated by FT-IR spectra. Disodium salt of terephthalic acid photoluminescence probing technology and radical scavenging measurements were carried out to identify the reactive oxygen species. The different parameters that affect MB degradation rate were evaluated. Moreover, the efficiency of recycled the SCP 1 and the mechanism of degradation of MB dye was investigated.