Investigation of g-C3N4/ZnAl2O4 and ZnO/ZnAl2O4 nanocomposites: From synthesis to photocatalytic activity of pollutant dye model

The fabrication of nanocomposite photocatalytsts with excellent photocatalytic activity is an important step in the improved degradation of organic dyes. A series of nanocomposite photocatalysts was synthesized with g-C₃N₄ and ZnO loading contents of 10, 20 and 30%. The nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). The optical band gaps of g-C₃N₄, ZnO and ZnAl₂O₄ were about 2.79, 3.21 and 3.55 eV, respectively. Methylene blue (MB) was degraded over the prepared photocatalysts under UV irradiation. Photocatalytic activity was about 9.1 and 9.6 times higher, respectively, on 20%g-C₃N₄/ZnAl₂O₄ and 20%ZnO/ZnAl₂O₄ nanocomposite photocatalysts than on pure ZnAl₂O₄ spinel powders. Recycling experiments showed that 20%g-C₃N₄/ZnAl₂O₄ and 20%ZnO/ZnAl₂O₄ nanocomposite photocatalysts exhibited good stability after five cycles of use.     

Photosensitization of Fe3O4/ZnO by AgBr and Ag3PO4 to fabricate novel magnetically recoverable nanocomposites with significantly enhanced photocatalytic activity under visible-light irradiation

In this paper, novel quaternary Fe₃O₄/ZnO/AgBr/Ag₃PO₄ nanocomposites with different weight percents of Ag₃PO₄ were successfully prepared through refluxing method at 96 °C. The as-prepared products were characterized with XRD, EDX, SEM, TEM, UV-vis DRS, FT-IR, PL, and VSM techniques to determine their phase structure, purity, morphology, spectroscopic, and magnetic properties. Photocatalytic degradation of rhodamine B under visible-light irradiation indicated that the nanocomposite with 20% of Ag₃PO₄ has the best activity. Photocatalytic activity of this nanocomposite is nearly 68, 5.0, and 3.4-folds greater than those of the Fe₃O₄/ZnO, Fe₃O₄/ZnO/AgBr, and Fe₃O₄/ZnO/Ag₃PO₄ samples in degradation of rhodamine B, whereas 17, 6.7, and 2.8-folds greater in degradation of methylene blue, respectively. The activity enhancement was mainly ascribed to the enhanced visible-light absorption ability and formation of tandem n-n heterojunctions between counterparts of the nanocomposites, which facilitate the generation and separation of charge carriers. An additional advantage of these photocatalysts is magnetic recoverability using external magnetic field. In addition, using different scavengers, superoxide ion radicals were identified as the main oxidative species in the degradation reaction of rhodamine B. Finally, photocatalytic stability of the nanocomposite was evaluated for six cycles.     

Fe3O4/ZnO/CoWO4 nanocomposites: Novel magnetically separable visible-light-driven photocatalysts with enhanced activity in degradation of different dye pollutants

A series of novel magnetically separable Fe₃O₄/ZnO/CoWO₄ nanocomposites with different contents of CoWO₄ were fabricated using a facile refluxing method at 96 °C followed by a calcination step. The structure, purity, morphology, spectroscopic, and magnetic properties of the prepared samples were characterized by XRD, EDX, SEM, TEM, UV–vis DRS, FT-IR, PL, and VSM techniques. Photocatalytic activity of the nanocomposites was investigated by degradation of rhodamine B, methylene blue, methyl orange, and fuchsine under visible-light irradiation. The results showed remarkably enhanced activity for the Fe₃O₄/ZnO/CoWO₄ (30%) nanocomposite relative to the Fe₃O₄/ZnO and Fe₃O₄/CoWO₄ samples. The degradation rate constant of RhB over the optimal nanocomposite is nearly 24 and 5 times higher than those of the Fe₃O₄/ZnO and Fe₃O₄/CoWO₄ samples, respectively. The intensive absorption of visible light and separation efficiency of the photogenerated electron–hole pairs in the ternary nanocomposites were confirmed by UV–vis DRS and PL techniques, respectively. In addition, a plausible mechanism for separation of the electron–hole pairs based on p–n heterojunction was proposed.     

Dual Z-scheme heterojunction g-C3N4/Ag3PO4/AgBr photocatalyst with enhanced visible-light photocatalytic activity

Recently, there has been a significant interest in developing high-performance photocatalysts for removing organic pollutants from water environment. Herein, a ternary graphitic C₃N₄ (g-C₃N₄)/Ag₃PO₄/AgBr composite photocatalyst is synthesized using an in-situ precipitation-anion-exchange process and characterized by several spectroscopic and microscopic techniques. During the photocatalytic reaction, X-ray photoelectron spectroscopy clearly illustrated the formation of metallic Ag on the g-C₃N₄/Ag₃PO₄/AgBr composite surface. The ternary composite photocatalyst demonstrated an increased photoactivity under visible light (>420 nm), achieving a complete decolorization of methyl orange (MO) in 5 min. The ternary g-C₃N₄/Ag₃PO₄/AgBr hybrid was also applied to the 2-chlorophenol degradation under visible light, further confirming its excellent photocatalytic activity. In addition, quenching experiments revealed that holes (h⁺) and O₂^?– were the major attack species in the decolorization of MO. The enhanced photoactivity of g-C₃N₄/Ag₃PO₄/AgBr results from the efficient transfer/separation of photoinduced charges with the dual Z-scheme pathway and the charge recombination sites on the formed Ag particles.     

Fabrication of magnetically recoverable Fe3O4/CdS/g-C3N4 photocatalysts for effective degradation of ciprofloxacin under visible light

Photocatalytic technology is an environmentally safe method of eliminating organic pollutants and antibiotics in wastewater. In this research, the performance of Fe₃O₄/CdS/g-C₃N₄ (FCN) photocatalyst for degradation of antibiotics was studied. The composite photocatalysts with different concentrations of g-C₃N₄ were prepared. FCN has better photocatalytic activity than degradation dyes in removal of antibiotics under visible light. This indicates that FCN could effectively hinder the recombination of carriers, and the addition of g-C₃N₄ increases the optical response range of CdS. At the same time, the introduction of Fe₃O₄ magnetic nanoparticles overcomes the problem of difficulty in recovery of the powder photocatalyst. The photocatalytic activity is not reduced to any significant after three cycles of use.     

Novel g-C3N4 nanosheets/CDs/BiOCl photocatalysts with exceptional activity under visible light

We fabricated novel ternary nanocomposites through integration of C-dots (carbon dots), BiOCl, and nanosheets of graphitic carbon nitride (g-C₃N₄ nanosheets) by a cost-effective route. The fabricated photocatalysts were subsequently characterized by XRD, EDX, TEM, HRTEM, XPS, FT-IR, UV-vis DRS, TGA, BET, and PL methods to gain their structure, purity, morphology, optical, textural, and thermal properties. In addition, the degradation intermediates were identified by gas chromatography-mass spectroscopy (GC-MS). Photocatalytic performance of the synthesized samples was studied by photodegradations of three cationic (RhB, MB, and fuchsine), one anionic (MO) dyes, one colorless (phenol) pollutant and removal of an inorganic pollutant (Cr(VI)) under visible light. It was revealed that the ternary nanocomposite with loading 20% of BiOCl illustrated superlative performances in the selected photocatalytic reactions compared with the corresponding bare and binary photocatalysts. Visible-light photocatalytic activity of the g-C₃N₄ nanosheets/CDs/BiOCl (20%) nanocomposite was 42.6, 27.8, 24.8, 20.2, and 15.9 times higher than the pure g-C₃N₄ for removal of RhB, MB, MO, fuchsine, and phenol, respectively. Likewise, the ternary photocatalyst showed enhanced activity of 15.3 times relative to the g-C₃N₄ in photoreduction of Cr(VI). Moreover, the ternary nanocomposite exhibited excellent chemical stability and recyclability after five cycles. Finally, the mechanism for improved photocatalytic performance was discussed based on the band potential positions.     

Ag/αFe2O3-rGO novel ternary nanocomposites: Synthesis,characterization, and photocatalytic activity

In this research, novel ternary Ag/αFe₂O₃-rGO nanocomposites with various contents of GO were synthesized via a facile one-pot hydrothermal method. Ag/αFe₂O₃-rGO nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrometer (EDX), photoluminescence (PL) spectroscopy, and Fourier transform infrared (FTIR). The results showed that hematite nanoparticles and Ag nanoparticles were well decorated on the graphene surface. Photocatalytic activity of Ag/αFe₂O₃-rGO ternary nanocomposites and pure Ag/αFe₂O₃ was investigated for photodegradation of Congo red dye solution as a model pollutant under UV light irradiation. The ternary nanocomposite with 1.8?mg/ml GO aqueous solution concentration shows higher degradation efficiency under UV light irradiation than the pure Ag/αFe₂O₃ and the nanocomposites with other GO aqueous solution concentrations. It was observed that the adsorption of the dyes on the nanocomposites surface is dependent on the graphene content due to a decrease in the recombination rate, particles size, and increase charge carrier transfer. The results show that the Ag/αFe₂O₃-rGO nanocomposite can be used as an excellent photocatalytic material for degradation of Congo red dye in wastewater. A possible photocatalytic mechanism was proposed for degradation of Congo red dye.     

Au nanoparticles-doped g-C3N4 nanocomposites for enhanced photocatalytic performance under visible light illumination

Surface and bandgap engineering of graphitic carbon nitride (g-C₃N₄) could be vital in enhancing photocatalytic performance by suppressing the recombination rate of photogenerated electron-hole pairs. The present report investigated the doping effects of various wt.% (0.2–5.0%) of gold nanoparticles (Au NPs) to g-C₃N₄ (Au/g-C₃N₄) for the enhancement of the photocatalytic efficiency of g-C₃N₄ nanocomposites. A straightforward and cost-effective synthesis methodology has been applied for the desired nanocomposites. Relevant characterization tools such as XRD, XPS, TEM, FTIR, and UV–Vis were utilized to analyze various physicochemical properties. The TEM images clearly show that spherical Au NPs were homogeneously distributed into the thin carbon nitride graphitic layers, confirming the successful doping of Au. The higher-magnification TEM image confirms that the sizes of the Au NPs varied from 15 to 25 nm. The photoactivity of the newly designed Au/g-C₃N₄ nanocomposites has been evaluated for the degradation of both methylene blue dye and the drug gemifloxacin mesylate, and their efficiencies were compared with that of bare g-C₃N₄. Our findings revealed that Au/g-C₃N₄ nanocomposites with various Au contents had superior photocatalytic activity compared to bare g-C₃N₄. However, the 1%Au/g-C₃N₄ nanocomposite could be considered the optimum photocatalyst, producing 95.13% destruction of the target dye molecule in 90 min, in contrast to the 69% achieved with bare g-C3N4, under the clean energy of visible light illumination. Additionally, the photodegradation rate of the 1%Au/g-C₃N₄ nanocomposite is 2.69 times higher than the rate of bare g-C₃N₄. This report might open a new gateway towards a straightforward and cost-effective synthesis approach for Au/g-C₃N₄ nanocomposites and provides a smooth and robust platform for the utilization of this new nanocomposite for environmental remediation processes.     

Assembled porous Fe3O4@g-C3N4 hybrid nanocomposites with multiple interface polarization for stable microwave absorption

Magnetic/dielectric composites can offer good electromagnetic impendence. However, the strategy for embodying strong absorbing ability and broad effective absorption band simultaneously is a significant challenge. Therefore, assembled porous Fe₃O₄@g-C₃N₄ hybrid nanocomposites have been designed and synthesized, in which porous Fe₃O₄ nanospheres assembled by ~ 3?nm Fe₃O₄ nanoparticles are surrounded by g-C₃N₄. The introduction of g-C₃N₄ improves dielectric loss ability at 2–18?GHz and magnetic loss ability at 2–10?GHz, and enhances attenuation constant, and increases electromagnetic impedance degree. These merits ensure that assembled porous Fe₃O₄/g-C₃N₄ hybrid nanocomposites deliver superior microwave absorption performance, such as effective absorption bandwidth, f_E, (reflection loss less ??10?dB) exceeding 5?GHz at 2.0–2.3?mm, the maximal f_E of 5.76?GHz and minimal reflection loss of at least ??20?dB with thickness ranging from 2.3 to 10.0?mm, avoiding the sensitivity of absorption properties to absorbing layer thickness. Stable microwave absorbing performance originates from multi-interfacial polarization, multi-reflection, enhanced electromagnetic loss capability, and good electromagnetic impedance. Our study offers a new idea for stable microwave absorber at 2–18?GHz.     

Insight into the adsorption and photocatalytic properties of in-situ synthesized g-C3N4/SnS2 nanocomposite

In this paper, a novel g-C₃N₄/2 wt% SnS₂ nanocomposite was successfully synthesized using an in-situ growth of SnS₂ on g-C₃N₄. X-ray diffraction (XRD), atomic force microscopy (AFM), Brunauer-Emmett-Teller (BET) method, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectrometer were used to characterize the photocatalysts. Exploring adsorption behavior, as an importatnt stage during photocatalytic reactions, is of great importance. Hence, both adsorption and photocatalytic performance of the synthesized photocatalysts have been investigated in detail. The adsorption isotherm fittings exhibited that Freundlich and Langmuir-Freundlich models can be applied to the methylene blue (MB) adsorption on the photocatalysts, indicating surface heterogeneity should be considered. A pseudo-second-order model was fitted to explore the adsorption kinetics. According to the observed redshift in the Fourier transform infrared spectroscopy (FTIR) result of g-C₃N₄/SnS₂ nanocomposite, π-π interaction was dominant during MB adsorption. Also, a slight redshift and significant PL intensity reduction in g-C₃N₄/SnS₂ nanocomposite led to 96% photocatalytic efficiency after 180 min under visible light radiation. The kinetics of photodegradation over g-C₃N₄/SnS₂ was about 9 and 3 times higher than those of g-C₃N₄ and SnS₂ photocatalysts, respectively. The superoxide and hydroxyl radicals were the main reactive species in the photocatalytic degradation with a Z-scheme charge transfer mechanism. The g-C₃N₄/SnS₂ nanocomposite was found to be remarkably stable after three consecutive cycles of MB degradation.     

Studies on highly conducting Polypyrrole/Fe3O4 nanocomposites

Polypyrrole (PPy)/Fe₃O₄ nanocomposites were in situ synthesized using chemical oxidative polymerization in an aqueous solution of FeCl₃.6H₂O, in presence of different Fe₃O₄ loadings (0%–16.52%). These composites were characterized through a 4 Probe electrical conductivity measurement technique, Fourier Transform infrared spectroscopy, energy dispersive X‐ray spectroscopy, scanning electron microscopy, X‐ray diffraction, thermo gravimetric analysis, and vibrating sample magnetometer. Results showed maximum electrical conductivity of 75.28 S/cm for the 2.52% Fe₃O₄ loaded nanocomposite and with improved thermal stability compared with the host PPy. Furthermore, a linear relationship between saturated magnetization M_s and % composition of Fe₃O₄ in the above nanocomposites was observed, showing 6.34 emu/g at 16.52% Fe₃O₄/PPy nanocomposite. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Structure and magnetic properties of regenerated cellulose/Fe3O4 nanocomposite films

Cellulose nanocomposites containing high contents of Fe₃O₄ nanoparticles were successfully prepared with regenerated cellulose films as a matrix and mixture solutions of Fe²⁺/Fe³⁺ as precursors. The structure and properties of the magnetic nanocomposite films were investigated with X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and vibrating sample magnetometry. Fe₃O₄ nanoparticles as prepared were irregular spheres and were homogeneously dispersed in the cellulose matrix. With an increase in the concentration of precursors from 0.2 to 1.0 mol/L, the content of Fe₃O₄ nanoparticles in the dried nanocomposites increased from 12 to 39 wt %, and the particle diameter increased from 32 to 64 nm. The cellulose nanocomposite films demonstrated superparamagnetic behavior, and their saturation magnetizations were in the range 4.2–21.2 emu/g, which were related to the increase in Fe₃O₄ nanoparticle content. With increasing nanophase content, the nanocomposite films displayed significantly anisotropic magnetic properties in the parallel and perpendicular directions. This study provided a green and facile method for the preparation of biobased nanocomposite films with high nanophase content and excellent magnetic properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Facile Synthesis of FeCo/Fe3O4 Nanocomposite with High Wave-Absorbing Properties

The FeCo/Fe₃O₄ nanocomposite was synthesized using the hydrothermal approach, in which the FeCo alloy and Fe₃O₄ are formed by one step. The structure of the FeCo/Fe₃O₄ nanocomposite was characterized by means of Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray energy-dispersive spectrometer spectroscopy (EDX). They show that the mass ratio of FeCo/Fe₃O₄ strongly depends on the reaction temperature. Such various architectures follow a stepwise growth mechanism of the composites prepared in various reaction temperatures were also discussed. It indicates that this strategy is facile, effective and controllable for the synthesis of FeCo/Fe₃O₄ by the one-step method. Furthermore, the magnetic and wave-absorbing properties of the nanocomposites with various structures were investigated in detail. The results show that the FeCo/Fe₃O₄ with higher mass ratio has higher magnetic properties. Moreover, the FeCo/Fe₃O₄ nanocomposite shows high wave-absorbing properties (e.g., −37.9 dB), which are expected to apply in microwave absorbing materials.     

Mesoporous BiVO4/2D-g-C3N4 heterostructures for superior visible light-driven photocatalytic reduction of Hg(II) ions

In this contribution, a Z-scheme mesoporous BiVO₄/g-C₃N₄ nanocomposite heterojunction with a considerable surface area and high crystallinity was synthesized by a simple soft and hard template-assisted approach. This material demonstrates superior visible light-driven photocatalysis for the photoreduction of Hg(II) ions. TEM and XRD results show that the mesoporous BiVO₄ NPs, with a monoclinic phase and an ellipsoid-like shape, are highly dispersed onto the porous 2D surfaces of g-C₃N₄ nanosheets with a particle size of 5–10 nm. The obtained BiVO₄/g-C₃N₄ nanocomposites with a p-n heterojunction show significantly enhanced Hg(II) photoreduction efficiency compared to the mesoporous BiVO₄ NPs and pristine g-C₃N₄. Among all synthesized photocatalysts, the 1.2% BiVO₄/g-C₃N₄ nanocomposite indicated the highest photoreduction of Hg(II) performance, reaching ~ 100% within 60 min; this result is 3.9 and 4.5 –fold larger than that of the BiVO₄ NPs and pristine g-C₃N₄. The Hg(II) photoreduction rates highly increase to 208.90, 314.95, 411.23 and 418.68 μmol g⁻¹min⁻¹ for the mesoporous 0.4, 0.8, 1.2 and 1.6% BiVO₄/g-C₃N₄ nanocomposites, respectively. The reduction rate of the mesoporous 1.2% BiVO₄/g-C₃N₄ nanocomposite demonstrated a 5.2 and 3.8 times larger increase than that of the pristine g-C₃N₄ nanosheets and pure BiVO₄ NPs. The superior Hg(II) photoreduction efficiency was ascribed to decreased carrier recombination and the improved utilization of visible light by constructing BiVO₄/g-C₃N₄ nanocomposites with a p-n junction. Transient photocurrent measurement and photoluminescence spectra were employed to confirm the possible Hg(II) photoreduction mechanism over these BiVO₄/g-C₃N₄ photocatalysts. This research provides an accessible route for the nanoengineered design of mesoporous BiVO₄/g-C₃N₄ heterostructures that demonstrated unique photocatalytic performance.     

Preparation and photocatalytic activity of g-C3N4/TiO2 heterojunctions under solar light illumination

The solar light sensitive g-C₃N₄/TiO₂ heterojunction photocatalysts containing 20, 50, 80, and 90 wt% graphitic carbon nitride (g-C₃N₄) were prepared by growing Titania (TiO₂) nanoparticles on the surfaces of g-C₃N₄ particles via one step hydrothermal process. The hydrothermal reactions were allowed to take place at 110 °C at autogenous pressure for 1 h. Raman spectroscopy analyses confirmed that an interface developed between the surfaces of TiO₂ and g-C₃N₄ nanoparticles. The photocatalyst containing 80 wt% g-C₃N₄ was subsequently heat treated 1 h at temperatures between 350 and 500 °C to improve the photocatalytic efficiency. Structural and optical properties of the prepared g-C₃N₄/TiO₂ heterojunction nanocomposites were compared with those of the pristine TiO₂ and pristine g-C₃N₄ powders. Photocatalytic activity of all the nanocomposites and the pristine TiO₂ and g-C₃N₄ powders were assessed by the Methylene Blue (MB) degradation test under solar light illumination. g-C₃N₄/TiO₂ heterojunction photocatalysts exhibited better photocatalytic activity for the degradation of MB than both pristine TiO₂ and g-C₃N₄. The photocatalytic efficiency of the g-C₃N₄/TiO₂ heterojunction photocatalyst heat treated at 400 °C for 1 h is 1.45 times better than that of the pristine TiO₂ powder, 2.20 times better than that of the pristine g-C₃N₄ powder, and 1.24 times better than that of the commercially available TiO₂ powder (Degussa P25). The improvement in photocatalytic efficiency was related to i) the generation of reactive oxidation species induced by photogenerated electrons, ii) the reduced recombination rate for electron-hole pairs, and iii) large specific surface area.     

Construction of g-C3N4/TiO2/Ag composites with enhanced visible-light photocatalytic activity and antibacterial properties

In this study, the multifunctional carbon nitride based composite graphitic-C₃N₄ (g-C₃N₄)/TiO₂/Ag was prepared through a simple and efficient vacuum freeze-drying route. TiO₂ and Ag nanoparticles were demonstrated to decorate onto the surface of g-C₃N₄ sheet. In the ultraviolet–visible absorption test, a narrower band gap and red-shift of light absorption edge were observed for g-C₃N₄/TiO₂/Ag compared to pristine g-C₃N₄ and single-component modified g-C₃N₄/TiO₂. The photodegradation property of g-C₃N₄/TiO₂/Ag was investigated toward the degradation of methylene blue (abbreviated as MB) under the irradiation of visible light. These results indicated that the degradation performance of organic dyes for g-C₃N₄/TiO₂/Ag was obviously improved compared with g-C₃N₄/TiO₂ and g-C₃N₄. The reaction rate constant of MB degradation for g-C₃N₄/TiO₂/Ag was 4.24 times higher than that of pristine g-C₃N₄. In addition, such rationally constructed nanocomposite presented evidently enhanced antibacterial performance against the Gram-negative Escherichia coli. Concentration dependent antibacterial performance was systematically investigated. And 84% bacterial cell viability loss had been observed at 500 μg/mL g-C₃N₄/TiO₂/Ag within 2 h visible light irradiation.     

Facile synthesis of WO3 nanorods/g-C3N4 composites with enhanced photocatalytic activity

In this paper, WO₃ nanorods (NRs)/g-C₃N₄ composite photocatalysts were constructed by assembling WO₃ NRs with sheet-like g-C₃N₄. The as-synthesized photocatalysts were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, UV–vis diffuse reflectance spectroscopy and photoluminescence. The photocatalytic activity of the photocatalysts was evaluated by degradation of Rhodamine B (RhB) under simulated sunlight irradiation. Compared to pristine WO₃ NRs and g-C₃N₄, WO₃ NRs/g-C₃N₄ composites exhibit greatly enhanced photocatalytic activities. The enhanced performance of WO₃ NRs/g-C₃N₄ composite photocatalysts was mainly ascribed to the synergistic effect between WO₃ NRs and g-C₃N₄, which improved the photogenerated carrier separation. A possible degradation mechanism of RhB over the WO₃ NRs/g-C₃N₄ composite photocatalysts was proposed.     

Graphene/Fe3O4 nanocomposite: Interplay between photo-Fenton type reaction,and carbon purity for the removal of methyl orange

Graphene/Fe₃O₄ nanocomposites obtained via soft chemical methodis have been characterized for their crystallinity, morphology, microstructure,optical bandgap, vibrational modes and magnetic properties. Graphenesheets decorated with magnetite nanoparticles are employed to investigatetheir photocatalytic response against methyl orange. The study revealsthat the conducting nature of graphene, engineered bandgap and photoFenton like reaction synergistically govern the efficient photocatalyticactivity of nanocomposite. Interestingly, it is observed that methylorange can be completely removed i.e., upto 99.24% by graphene/Fe₃O₄ nanocomposite, whereas the removal efficiency is 43% for Fe₃O₄ nanoparticles, alone. The presence of graphene endows the delay in chargecarriers' recombination whereas, photo Fenton like reaction stimulatesthe generation of reactive oxygen species. This ultimately leads to thehighly enhanced photocatalytic activity and complete removal of methylorange. The magnetically separable photocatalyst, presented in thiswork, offers great prospects for fast and economical decontamination of dye polluted water.     

Magnetically recoverable Fe3O4@SBA-15: An improved catalyst for three component coupling reaction of aldehyde,amine and alkyne

We have synthesized Fe₃O₄ nanoparticles on mesoporous SBA-15 by an “in situ” approach. The synthesized nanocomposite material was well characterized using wide and low angle XRD, N₂ adsorption–desorption isotherm, TEM, FTIR, XPS, and VSM analysis. The Fe₃O₄@SBA-15 nanocomposite material was used as a magnetically recoverable catalyst (MRC) for three component coupling reaction of aldehyde, amine and alkyne. The reported catalyst was recycled up to five times without significant loss in its catalytic activity.     

Preparation of g-C3N4/MoS2 Composite Material and Its Visible Light Catalytic Performance

The g-C₃N₄ nanosheet was prepared by calcination method, the MoS₂ nanosheet was prepared by hydrothermal method. The g-C₃N₄/MoS₂ composites were prepared by ultrasonic composite in anhydrous ethanol. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible spectroscopy, and photoluminescence techniques were used to characterize the materials. The photocatalytic degradation of Rhodamine B (Rh B) by g-C₃N₄/MoS₂ composites with different mass ratios was investigated under visible light. The results show that a small amount of MoS₂ combined with g-C₃N₄ can significantly improve photocatalytic activity. The g-C₃N₄/MoS₂ composite with a mass ratio of 1:8 has the highest photocatalytic activity, and the degradation rate of Rh B increases from 50 to 99.6%. The main reason is that MoS₂ and g-C₃N₄ have a matching band structure. The separation rate of photogenerated electron–hole pairs is enhanced. So the g-C₃N₄/MoS₂ composite can improve the photocatalytic activity. Through the active material capture experiment, it is found that the main active material in the photocatalytic reaction process is holes, followed by superoxide radicals.