Simple Microwave Irradiation Method Research Articles

Hydrophobic ionic liquid (IL)-based magnetic adsorbents: the way forward to remediate water pollution

In this investigation, bare and hydrophobic IL-modified FeO nanoparticles (NPs) have been synthesized using microwave irradiation.

A strategy of adjusting band alignment to improve photocatalytic degradation and photocatalytic hydrogen evolution of CuSbS2

Photocatalytic technology based on heterojunction structure has been proved to be an effective way to solve environmental pollution and energy crisis. The effective carrier concentration plays an important role in improving the performance of heterojunction photocatalyst. In this work, CuSbS2 (CAS)-CdS-ZnO was prepared by simple 3-steps microwave irradiation method to reveal the influence of energy band structure on photocatalytic performance. Adding CdS could regulate band alignment to translate the “cliff-like” conduction band offset of CAS-ZnO to “spike-like”. That could effectively reduce the carrier recombination rate to improve the photocatalytic degradation activity, which could completely degraded Rhodamine B (RhB) after 80 min under a solar simulation, highest rate constant (0.02028 min−1) and good stability. Furthermore, the transformation of charge transfer mechanism from the Z-type to Ⅱ-type by adding CdS were confirmed by experiments and density functional theory (DFT) calculations. This change could raise the energy level of photoelectrons, resulting in CAS-CdS-ZnO with a certain photocatalytic hydrogen evolution capacity (42.37 μmol g−1 h−1). This work reveals the important role of band structure in photocatalytic properties and applications of heterojunction.

Microwave assisted Acetylation of Amines using Imidazole Hydrochloride under solvent-free condition

A simple and novel microwave irradiation method has been developed for N-acetylation of both aliphatic and aromatic amines with N,N-dimethylacetamide via Nacetyl imidazole by using Imidazole hydrochloride under solvent-free condition. The method proved more eco-friendly and economic.

Microwave-assisted synthesis of ZnAl-LDH/g-C3N4 composite for degradation of antibiotic ciprofloxacin under visible-light illumination

Ciprofloxacin (CIP) is a fluoroquinolone family antibiotic pollutant. CIP existence in water environment has been rising very fast in day-to-day life and subsequently, it gives enormous health issues for humans because of its potent biological activity. To encounter this, current researchers are focusing on the development of highly efficient visible light semiconductor nanocomposites with potential photocatalytic activity. In the present work, we have successfully synthesized highly efficient zinc-aluminum layered double hydroxides with graphitic carbon nitride (ZALDH/CN) composites via a simple microwave irradiation method first time for the degradation of CIP under visible light. The fabricated materials are subsequently characterized by various spectroscopic techniques. UV–Vis DRS, TRFL, XRD, FT-IR, BET, FE-SEM, TEM, and XPS for optical, crystal structure, morphological, and elemental analysis. The main reactive intermediates which are formed during the photocatalytic degradation process were analyzed by LC-MS analysis. It is worth to note that, the optimized ZALDH/CN-10 composite showed the highest photo-degradation rate constant of 1.22 × 10−2 min−1 with 84.10% degradation is higher than bare CN and ZALDH photocatalysts. Based on the electron-hole pair trapping experiment results, possible CIP photo-degradation mechanism was also explained in the present study. With all results, this work demonstrates the ZALDH/CN composite materials showed a high synergistic effect with more specific surface area. Highest specific surface area leads to enhanced visible light adsorption capacity. Subsequently improved number of catalytically active sites. Furthermore, as compared with pure materials, composites of ZALDH/CN are having low electron-hole pair recombination. Consequently, the composites ZALDH/CN showed superior photocatalytic activity for antibiotic pollutant CIP degradation under visible-light illumination.

Incorporation of trimetallic nanoparticles to the SiO2 matrix for the removal of methylene blue dye from aqueous medium

The removal of toxic dyes from the wastewater is a serious concern. One of the commonly employed dyes in the textile industry is methylene blue (MB). Its presence in water not only reduces the aesthetic value of the water but also affects aquatic life. Considering this, we have worked on the designing of Bi2O3-SrO-FeO@SiO2 nanocomposite using a simple microwave irradiation method. The synthesized Bi2O3-SrO-FeO@SiO2 nanocomposite was characterized by various techniques such as scanning electron microscope, transmission electron microscope, X-Ray diffractometer, elemental mapping, Energy- dispersive X-Ray, and X-ray photoelectron spectrophotometer. The adsorption technique was utilized for the effective removal of MB using Bi2O3-SrO-FeO@SiO2 nanocomposite. Effects of various factors such as the concentration of MB, amount of Bi2O3-SrO-FeO@SiO2 nanocomposite, and reaction time were undertaken for getting some optimized parameters for the further experiments. Adsorption isotherm models such as Langmuir, Freundlich, and Temkin were employed for the adsorption data. Besides, adsorption kinetic models such as Pseudo- first order and Pseudo- second-order were also studied for determining the rate of the undertaken adsorption process. At last, the reusability of the Bi2O3-SrO-FeO@SiO2 nanocomposite was studied for six consecutive cycles for elaborating the practical application of the synthesized adsorbent.

A green synthesis of calcium silicate nanopowders from silica fume and marble sawing dust by a microwave irradiation-assisted route

Calcium silicate nanopowders have been successfully synthesized from solution mixtures of silica fume and marble sawing dust via a simple, fast and eco-friendly microwave irradiation method.

Honeycomb-like open-edged reduced-graphene-oxide-enclosed transition metal oxides (NiO/Co3O4) as improved electrode materials for high-performance supercapacitor

• Honeycomb reduced graphene oxide (HOrGO) serves as an efficient conductive network. • The HOrGO/TMOs (NiO/Co 3 O 4 ) hybrids were synthesized via microwave-assisted method. • The micron-sized (~100 μm) open edges of HOrGO NSs hold the NiO/Co 3 O 4 nanoparticles. • The HOrGO/TMOs hybrids deliver specific capacitance 910 F/g at scan rate 20 mV/s. • The HOrGO/TMOs hybrids exhibited high retention with stabile performance. Honeycomb-like open edges reduced graphene oxide nanosheets (HOrGO NSs) filled with transition metal oxides (TMOs) as NiO/Co 3 O 4 nanoparticles (NPs) has been synthesized by a simple and cost-effective microwave irradiation method. The microwave irradiation assisted synthesized HOrGO filled with NiO/Co 3 O 4 NPs (HOrGO/TMOs) hybrids exhibits high specific capacitance with improved cycling stability as excellent electrode materials for supercapacitors (SCs). The HOrGO NSs contains high surface area (~570 m 2 g −1 ) due to highly exfoliated nanostructure comprising open edges enriched morphology. In HOrGO/TMOs hybrids, the several micron-sized (~100 μm) open edges of HOrGO NSs holds the NiO/Co 3 O 4 NPs with finely separated thin few-layer graphene NSs. The structural/ morphological analysis of synthesized HOrGO NSs and HOrGO/TMOs hybrids were extensively characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectra, thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area. The HOrGO/TMOs hybrids deliver high specific capacitance of 910 F g −1 and high robust cycling stability with capacitance retention as 89.9% after continuous 2000 cycles. The proposed mechanism explain the microwave irradiation assisted formation of HOrGO/TMOs hybrids and provides a general and low-cost approach to synthesized high quality graphene hybrids materials for SCs application.

Expeditious and eco-friendly synthesis of spinel LiMn2O4 and its potential for fabrication of supercapacitors

Abstract Spinel LiMn2O4 has been gaining more attention for supercapacitor applications due to its abundance, low cost, environmental friendliness, and high energy density as well as good rate capability. In this work nanostructured multimetal oxide LiMn2O4 was synthesized using expeditious, eco-friendly, glucose mediated simple microwave irradiation method. A detailed study has been performed to correlate the phase structure, surface morphology, redox reaction at the electroactive species and its potential impact on the electrochemical performance as the electrode material. The synthesized spinel LiMn2O4 electrode exhibits a good specific capacitance of 276 F g −1 and 220 F g−1 in aqueous (KOH) and non-aqueous (LiClO4/ethylene carbonate (EC)) electrolytes respectively at a scan rate of 20 mV s−1. In aqueous electrolyte, the reaction kinetics of supercapacitors became very fast which is responsible for the exhibited high capacitance. Excellent capacitance retention of 90% even after 2000 cycles was achieved for this spinel structure. This indicates that the aqueous electrolyte and unique spinel structure are favourable for superfast redox kinetics of the prepared LiMn2O4 due to its higher ionic conductivity and electrochemical stability.

Hydrogen production and photocatalytic activity of g‐C3N4/Co‐MOF (ZIF‐67) nanocomposite under visible light irradiation

Herein, cobalt (Co)‐based metal–organic zeolitic imidazole frameworks (ZIF‐67) coupled with g‐C3N4 nanosheets synthesized via a simple microwave irradiation method. SEM, TEM and HR‐TEM results showed that ZIF‐67 were uniformly dispersed on g‐C3N4 surfaces and had a rhombic dodecahedron shape. The photocatalytic properties of g‐C3N4/ZIF‐67 nanocomposite were evaluated by photocatalytic dye degradation of crystal violet (CV), 4‐chlorophenol (4‐CP) and photocatalytic hydrogen (H2) production. In presence of visible light illumination, the photocatalytic dye results showed that 95% CV degradation and 53% 4‐CP degradation within 80 min. The H2 production of the g‐C3N4/ZIF‐67 composite was 2084 μmol g−1, which is 3.84 folds greater than that of bare g‐C3N4 (541 μmol g−1).

Rapid and Facile Microwave-Assisted Synthesis of Palladium Nanoparticles and Evaluation of Their Antioxidant Properties and Cytotoxic Effects Against Fibroblast-Like (HSkMC) and Human Lung Carcinoma (A549) Cell Lines.

We report here a simple microwave irradiation method (850 W, 3 min) for the synthesis of palladium nanoparticles (Pd NPs) using ascorbic acid (as reducing agent) and sodium alginate (as stabilizer agent). The synthesized nanoparticles were characterized using transmission electron microscopy (TEM), energy dispersive X-ray (EDX), X-ray diffraction spectroscopy (XRD), UV-Visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR) techniques. Antioxidant properties and cytotoxic effects of as-synthesized Pd NPs and Pd (II) acetate were also assessed. UV-Vis study showed the formation of Pd NPs with maximum absorption at 345 nm. From TEM analysis, it was observed that the Pd NPs had spherical shape with particle size distribution of 13-33 nm. Based on DPPH radical scavenging activity and reducing power assay, the antioxidant activities of Pd NPs were significantly higher than the Pd (II) acetate (p < 0.05). At the same concentration of 640 μg/mL, the scavenging activities were 32.9 ± 3.2% (Pd (II) acetate) and 27.2 ± 2.1% (Pd NPs). For A549 cells treated 48 h with Pd NPs, Pd (II) acetate, and cisplatin, the measured concentration necessary causing 50% cell death (IC50) was 7.2 ± 1.7 μg/mL, 32.1 ± 2.1 μg/mL, and 206.2 ± 3.5 μg/mL, respectively. On HSkMC cells, the IC50 of the Pd NPs (320 μg/mL) was higher compared to Pd (II) acetate (228.7 ± 3.6 μg/mL), which confirmed lower cytotoxicity of the Pd NPs.

Enrichment of optical, magnetic and photocatalytic properties in PVP capped CdO/SnO2 nanocomposites synthesized by microwave irradiation method

In this research study, the PVP capped CdO/SnO2, hybrid CdO/SnO2, and pure CdO nanocomposites were synthesized using simple chemical reaction and microwave irradiation method. The semantic approach studies the structural, morphological, elemental composition, optical, magnetic, thermal properties. XRD studies confirm that the particle size decreased in PVP capped CdO/SnO2 and CdO/SnO2 nanocomposites compared to pure CdO sample. Also, the existence of diffraction peaks of both CdO and SnO2 in fabricated hybrid CdO/SnO2 nanocomposite proves that the lattice combination of CdO and SnO2. The SEM and TEM images conclude that after doping of SnO2 and PVP with CdO nanoparticles, the particle structure transformed to rod-like morphology. FTIR spectrum of SnO2 and PVP: SnO2 doped CdO and their functional groups were studied. And also the presence of elemental composition analyzed by EDS spectrum. The UV absorption spectra results of SnO2 and PVP: SnO2 doped CdO states the red-shifted in the bandgap. An enhanced photocatalytic activity is observed in SnO2, PVP doped CdO nanocomposites. The thermal analysis curve of TGA and DTA confirms the thermal stability of synthesized nanocomposites. The CdO sample exhibits the ferromagnetic property. And Antiferromagnetism property is observed in SnO2, PVP doped CdO nanocomposites.

Manganese Doped Hydroxyapatite Nanoparticles Based Enzyme-Less Electrochemical Sensor for Detecting Hydroquinone.

Manganese (Mn) doped hydroxyapatite (HA) nanoparticles were synthesized by a simple microwave irradiation method and characterized using XRD, SEM, micro-Raman, FTIR, XPS and vibrating sample magnetometer (VSM) methods. The as prepared 3 M% Mn doped HA (3 M% Mn-HA) nanoparticles modified glassy carbon electrode (GCE) showed an excellent electrocatalytic activity towards the oxidation of hydroquinone (HQ). The electrochemical studies demonstrated that the 3 M% Mn-HA nanoparticles modified GCE detects HQ linearly over a wide concentration range of 1.0×10-8 to 1.6×10-4 M with the lowest detection limit of 11 nM at neutral pH (7.0) in PBS. Furthermore, Mn-HA modified GCE exhibited an excellent stability, reproducibility and anti-interference ability against a number of potential electroactive species and metal ions and proved to be useful for the estimation of the HQ in tap water and industry waste water with satisfactory recovery.

Comparative Studies of Magneto-Optical and Photocatalytic Properties of Magnetically Recyclable Spinel ZnFe2O4 Nanostructures by Combustion Methods

Spinel ZnFe2O4 nanoparticles (NPs) were successfully synthesized by a simple microwave irradiation method (MIM) using glycine as the fuel. For the comparative study purpose, it was also prepared by conventional heating (CHM) method. Powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), high resolution scanning electron microscope (HR-SEM), high resolution transmission electron microscope (HR-TEM), energy dispersive X-ray (EDX) spectra, selected area electron diffraction (SAED) analysis showed that the samples were pure phase spinel ZnFe2O4 nanoparticles-like morphology without any other secondary phase impurity. UV-Visible diffuse reflectance spectra (DRS) and room temperature photoluminescence (PL) spectra were confirmed the optical bandgap ([Formula: see text] and defects state of the samples. The calculated [Formula: see text] values of the samples are 1.91[Formula: see text]eV and 2.08[Formula: see text]eV for ZnFe2O4-MIM and ZnFe2O4-CHM, respectively. Vibrating sample magnetometer (VSM) analysis show the Ms value is 37.66[Formula: see text]emu/g for ZnFe2O4-MIM, which is higher than ZnFe2O4-CHM (24.23 emu/g) sample, which confirm both the products showed superparamagnetic behavior. ZnFe2O4-MIM was found to have higher surface area than ZnFe2O4-CHM, which in turn leads to the improved performance toward the photocatalytic degradation (PCD) of 4-chlorophenol (4-CP) and it was found that the sample ZnFe2O4-MIM show higher PCD efficiency (91.43%) than ZnFe2O4-CHM (84.65%), also the samples show high activity, good reusability, remarkable stability and environmentally friendly materials for industrial and technological applications.

Electrocatalytic activity of C-dots for highly sensitive detection of Uric acid

Abstract Over the past decades, carbon based materials used as many applications, particularly, medicine, biosensors, catalysis and so on. The high potential C-dots (CDs) were synthesized via simple microwave irradiation method. As synthesized C-dots were characterized using many of the techniques, such as XRD, FT-IR, DRS UV vis spectroscopy. The CDs surface was analyzed using FESEM microscopy. Further the objective of the synthesized CDs was catalytic sensing of Uric Acid (UA). The CDs modified electrode gives better result than bare electrode. The electrochemical station comprises three electrode systems, calomel electrode as a reference electrode, platinum electrode as counter electrode and glassy carbon electrode (GCE) as a working electrode. The CDs modified electrode gives the sensing of 10-4M UA oxidation peak at 0.51 V at 50 mV scan rate using pH 7 buffer solution.

Investigation of electrochemical properties of microwave irradiated tungsten oxide (WO3) nanorod structures for supercapacitor electrode in KOH electrolyte

Rod-like morphology of tungsten oxide (WO3) nanostructures were successfully synthesized via simple microwave irradiation method for three different irradiation times. The Precipitation was obtained from a sodium tungstate salt solution and subsequent Microwave irradiation along with that furnace heating have been used to prepare the WO3 nanostructures. Further investigation shows that monoclinic and orthorhombic crystal structures with a well-grown rod-shaped morphology of as-synthesized samples which were confirmed by XRD and HRTEM analysis. The optical absorption was measured by UV–vis spectroscopy and its band gap was calculated as the average value of 3.58 eV. The functional group linked with WO3 was studied by Raman spectroscopy and confirmed the associated groups with WO3. Finally, the suitability of as-prepared nanostructures for electrochemical supercapacitor was investigated by Cyclic Voltammetry (CV) and Galvanic Charge-Discharge (GCD) analysis, which revealed their highest specific capacitance 44 Fg−1 at a current density of 0.5 Ag−1.

Efficient and Durable Oxygen Reduction Electrocatalyst Based on CoMn Alloy Oxide Nanoparticles Supported Over N-Doped Porous Graphene

Transition metal oxide derived materials are very important for various applications, such as electronics, magnetism, catalysis, electrochemical energy conversion, and storage. Development of efficient and durable catalysts for the oxygen reduction reaction (ORR), an important reaction in fuel cells and metal–air batteries, is highly desirable. Moreover, the futuristic catalysts for these applications need to be cost-effective in order to ensure a competitive edge for these devices in the energy market. This article describes the synthesis of a cost-effective and efficient electrocatalyst for ORR. It is based on supporting CoMn alloy oxide nanoparticles on N-doped porous graphene through a simple and scalable microwave irradiation method. Microwave irradiation was found to be very crucial for the fast creation of pores in the graphene framework with a concomitant formation of the CoMn alloy oxide nanoparticles. A series of catalysts have been synthesized by varying the Co:Mn ratio, among which, the one wi...

Structural and Optical properties of Mg doped Tungsten oxide prepared by Microwave irradiation method

The synthesis of magnesium doped Tungsten oxides (Mg:WO3) nanomaterial was achieved using a simple household microwave irradiation method. In which 3 and 10 wt% magnesium chloride were used to prepare the above material. The synthesized materials were structurally and optically characterized using various techniques like X- Ray Diffraction, FTIR, UV-DRS, PL and SEM-EDAX. The X-ray diffraction confirms clearly showed the presence of crystalline Mg: WO3 particles. Further, UV-DRS and FTIR result shows the presence of Mg: WO3 nanomaterials at specific wavelength. From UV-DRS the optical band gap energy increases to 3–3.15 eV compare to the pure materials. The scanning Electron Microscopy(SEM) analysis conforms that the synthesized Mg:WO3 was spherical in shape and has 30–40 nm size in diameter. EDAX confirms the Mg doped in the synthesized material. The emission spectra of the undoped and Mg doped samples were analyzed using PL spectroscopy.

Room-Temperature Superparamagnetism and Enhanced Photocatalytic Activity of Magnetically Reusable Spinel ZnFe2O4 Nanocatalysts

Spinel ZnFe2O4 nanoparticles (NPs) were successfully synthesized by a simple microwave irradiation method (MIM) using glycine as the fuel. For the comparative study purpose, it was also prepared by a conventional heating (CHM) method. Powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), high-resolution scanning electron microscope (HR-SEM), high-resolution transmission electron microscope (HR-TEM), energy-dispersive X-ray (EDX) spectra, and selected area electron diffraction (SAED) analysis showed that the samples were pure-phase spinel ZnFe2O4 nanoparticle-like morphology without any other secondary-phase impurity. UV-Visible diffuse reflectance spectra (DRS) and room temperature photoluminescence (PL) spectra confirmed the optical band gap (Eg) and defect state of the samples. The calculated Eg values of the samples are 1.98 and 2.11 eV for ZnFe2O4-CHM and ZnFe2O4-MIM, respectively. Vibrating sample magnetometer (VSM) analysis shows that the Ms value is 37.66 emu/g for ZnFe2O4-MIM, which is higher than the ZnFe2O4-CHM (24.23 emu/g) sample, which confirms that both the products showed a superparamagnetic behavior. ZnFe2O4-MIM was found to have a higher surface area than ZnFe2O4-CHM, which in turn leads to the improved performance towards the photocatalytic degradation (PCD) of methylene blue (MB), and it was found that the sample ZnFe2O4-MIM shows a higher PCD efficiency (91.43%) than ZnFe2O4-CHM (84.65%); also, the samples show high activity, good reusability, remarkable stability, and environmentally friendly materials for industrial and technological applications.

Ultrathin manganese dioxide nanosheets grown on partially unzipped nitrogen-doped carbon nanotubes for high-performance asymmetric supercapacitors

In this work, N-doped carbon nanotubes (NCNTS) have been easily unzipped using a chemical oxidation method to obtain porous and multi-defective partially unzipped N-doped carbon nanotubes (PU-NCNTs), which are promising as negative electrode materials for supercapacitors and are also suitable substrate materials for the efficient loading of ultrathin manganese dioxide (MnO2) nanosheets. Herein, the PU-NCNT/MnO2 composite was synthesized through a simple microwave irradiation method. Moreover, we have fabricated an asymmetric supercapacitor (ASC) using PU-NCNT/MnO2 composite as cathode, PU-NCNTs as anode and neutral aqueous Na2SO4 as electrolyte. Because of the synergistic effects of the PU-NCNTs electrode and the high capacitance as well as good rate performance of PU-NCNT/MnO2 composite, the asymmetric cell exhibited good electrochemical performance. The optimized ASC can be worked stably in the voltage window of 0–1.8 V and exhibited a maximum energy density of 14.76 Wh kg−1 at the current density of 1 A g−1. Additionally, the PU-NCNT/MnO2//PU-NCNT ASC exhibited long cycling stability with 80.5% specific capacitance retained after 1000 cycles at a current density of 1 A g−1. These encouraging results show that PU-NCNT/MnO2 could be promising materials for commercial use of supercapacitors.

A facile and one-pot synthesis of pure and transition metals (M = Co &amp; Ni) doped WO3 nanoparticles for enhanced photocatalytic performance

Cobalt (Co) and Nickel (Ni) doped tungsten oxide (WO3) nanoparticles were successfully synthesized by simple household microwave irradiation method without employing hydrothermal process. The samples have been characterized by various advanced techniques such as; powder X-ray diffraction (XRD), Transmission electron microscopy (TEM), UV–Vis spectra, Photoluminescence and Fourier transform infrared spectroscopy (FT-IR) analysis. The X-ray diffraction reveals that all samples are monoclinic phase of WO3 and the average crystalline size was observed to vary from 42 nm to 21 nm as the dopant content was introduced. The TEM images confirm the spherical shaped morphology and the size of the nanoparticles in nanoscale. The optical property of the pure WO3 was significantly improved by dopant content, which is confirmed by UV and PL studies. The photo catalytic activity of the nanoparticles was studied in the degradation reaction of Crystal Violet (CV) and Methylene blue (MB) under UV light irradiation. It was found that Ni doped WO3 showed superior performance of the photocatalytic activity of the pure WO3. The improved photocatalytic mechanism by Ni doping was also discussed.