Synthesis,characterization and photocatalytic activity study of aluminium doped BiSbO4 microflakes

Metal oxides have an extraordinary ability to generate charge carriers with significant importance in environmental remediation. For the degradation of different dyes, a one-step hydrothermal method was adopted to synthesize Al-doped BiSbO_4. While bismuth antimonate composite with reduced graphene oxide was synthesized by the simple ultra-sonication method. To investigate the structural confirmation, X-ray diffraction (XRD) was used. For studying morphology, scanning electron microscopy (SEM) was conducted. UV–Visible spectroscopy (UV) and Fourier transform infrared spectroscopy (FTIR) were used to observe the optical properties and vibrational modes of the as-synthesized BiSbO₄ nanoparticles and doped Al–BiSbO₄. The above-mentioned studies verify the formation of nanoparticles of Al-doped BiSbO₄. The synthesized composite was used to degrade the organic dyes such as methylene blue and crystal violet. The degradation efficiency of doped, undoped and composite is studied and compared. The results indicate the extraordinary efficiency of BiSbO₄/rGO composite to doped and bare samples for the degradation of dyes. It is confirmed by the degradation of different dyes that the BiSbO₄/rGO composite shows the best catalytic efficiency.     

Solvothermal synthesis of various C3N4 films on FTO substrates and their photocatalytic and sensing applications

This paper reports solvothermal syntheses of pristine and KOH–NaCl-modified melon and melon–rGO composite films without post annealing and their applications in photocatalysis and Cu²⁺ sensing. Melon seed-layer coating enhanced film adhesion to fluorine-doped tin oxide substrates. X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy were used to verify melon film structures. Assorted complex agents were studied to tailor film morphologies. (001)-Oriented nanorods were observed in KOH–NaCl-modified melon films. Constituent elements were determined based on their binding energies using X-ray photoelectron spectroscopy. Ultraviolet–visible and ultraviolet photoelectron spectroscopy were employed to confirm band gaps and valence band positions, respectively, of melon films. Associated energy-band diagrams were then constructed. The melon–rGO composite films exhibited superior photodegradation of methylene blue (degradation rate constant [k] ≅ 6.4 × 10⁻³/min) and rhodamine B (k ≅ 2.5 × 10⁻³/min) under visible-light irradiation. The performance was confirmed by nanorod structures, low photoluminescence emission, and high electrochemical surface areas. Furthermore, a reliable photoelectrochemical current density (~0.5 mA/cm²) at a 0.6-V bias was obtained for KOH–NaCl-modified melon and melon–rGO composite films. The KOH–NaCl-modified melon films demonstrated excellent selectivity between Cu²⁺ and Cr⁶⁺, indicating promising applications in Cu²⁺ sensing.     

Structure and room-temperature ferromagnetism evolution of Sn and Mn-doped NiO synthesized by a sol-gel process

The development of room temperature ferromagnetism is imperative for energy systems such as data storage in computers and spintronics. Herein we report a room temperature ferromagnetic study of Sn and Mn doped nickel oxide synthesized by sol gel method. The size and morphology of the samples are calculated using XRD and TEM analysis. The XRD and Fourier transform infrared (FTIR) results indicate that the synthesized NiO powders have a pure cubic structure. The variation in lattice parameters has been studied using the Rietveld refinement of X-ray diffraction pattern. The addition of dopants does not affect the structure of NiO. The presence of dopants in the doped NiO samples has been confirmed with Energy Dispersive Spectroscopy (EDS) analysis. The Photoluminescence (PL) spectrum shows enhanced luminescence intensity for Sn doped NiO than Mn doped NiO. The magnetic properties of the samples have been studied using Vibrating sample magnetometry (VSM). The pure and Mn doped NiO samples are found to exhibit ferromagnetism. The Sn doped NiO samples exhibit superparamagnetism making them suitable for applications in ferrofluids and as contrast agents for magnetic resonance imaging. The coercivity and magnetization of the Mn doped NiO samples are found to be enhanced compared to the pure NiO. The Sn doped NiO samples have very low value of coercivity compared with both pure and Mn doped NiO samples. The observed room temperature ferromagnetism in doped NiO makes it a suitable candidate for DMS devices such as MR imaging and magnetic delivery.     

Influence of functionalized reduced graphene oxide and compatibilizer on mechanical,thermal and morphological properties of polypropylene/polybutene-1 (PP/PB-1) blends

Polypropylene/Polybutene-1 (PP/PB-1) blends and nanocomposites containing pristine partially reduced graphene oxide (rGO) and chemically functionalized rGO (FrGO) with silane, and silane grafted with 1,12-dodecanediamine and 1,12-dodecanediol were studied. The effects of the chemical treatments on structure and thermal stability of rGO were first thoroughly investigated. Attenuated total reflectance Fourier infrared (ATR-FTIR) spectroscopy analyses of FrGO evidenced the existence of functional groups on rGO after each chemical treatment, while X-ray diffraction (XRD) results confirmed the effectiveness of the interlayer grafting process through shifting of the basal spacings as witnessed by increased d₀₀₂ values. Furthermore, thermogravimetric analysis (TGA) revealed that the functionalization of rGO resulted in improved thermal stability of rGO demonstrated by its increased thermal degradation temperature. The PP/PB-1 blends and their rGO and FrGO based nanocomposites were prepared by melt blending masterbatch process in the presence of an acrylic acid modified polypropylene compatibilizer (PP-g-AA). Mechanical testing showed that Young’s modulus and tensile strength of the PP/PB-1 blends significantly improved after co-addition of FrGO and PP-g-AA to form the nanocomposites, but it also endowed a drastic decrease in their elongation at break and especially in their impact strength. XRD analyses attested the successful formation of intercalated nanocomposites, and scanning electron microscopy (SEM) examinations disclosed a two-phase morphology consisting of PB-1 dispersed droplets in the PP matrix. SEM also indicated that the incorporation of PP-g-AA into the blends and the nanocomposites contributed to enhanced adhesion and dispersion of PB-1 phase and FrGO nanoparticles within the polymer matrix.     

Crystallographic,Energy Gap,Photoluminescence and Photo-Catalytic Investigation of Cu Doped Cd0.9Zn0.1S Nanostructures by Co-precipitation Method

In this work, the controlled synthesis of Cd_0.9Zn_0.1S, Cd_0.89Zn_0.1Cu_0.01S and Cd_0.87Zn_0.1Cu_0.03S nanostructures by chemical co-precipitation technique was reported. The XRD investigation confirmed the cubic structure on Zn/Cu-doped CdS without any secondary/impurity related phases. No modification in cubic structure was detected during the addition of Zn/Cu into CdS. The reduction of crystallite size from 63 to 40 Å and the changes in lattice parameter confirmed the incorporation of Cu into Cd_0.9Zn_0.1S and also the generation of Cu related defects. The shift of absorption edge along upper wavelength region and elevated absorption intensity by Cu doping can be accredited to the collective consequence of quantization and the generation of defect associated states. The enhanced optical absorbance and the reduced energy gap recommended that Cd_0.87Zn_0.1Cu_0.03S nanostructure is useful to enhance the efficiency of opto-electronic devices. The presence of Cd–S/Zn–Cd–S /Zn/Cu–Cd–S chemical bonding were confirmed by Fourier transform infrared investigation. The elevated green emission by Cu incorporation was explained by decrease of crystallite size and creation of more defects. Zn, Cu dual doped CdS nanostructures are recognized as the possible and also efficient photo-catalyst for the removal dyes like methylene blue. The enhanced photo-catalytic behavior of Zn, Cu dual doped CdS is the collective consequences of high density electron–hole pairs creation, enhanced absorbance in the visible wavelength, surface area enhancement, reduced energy gap and the formation of novel defect associated states. The stability measurement signified that Cu doped Cd_0.9Zn_0.1S exhibits superior dye removal ability and better stability even after 6 repetitive runs with limited photo-corrosion due to more charge carriers liberation, increased surface to volume ratio and creation of more defects.

     

Tailoring the properties of cerium doped zinc oxide/reduced graphene oxide composite: Characterization,photoluminescence study,antibacterial activity

Ce doped ZnO/rGO composite materials were prepared by a one-pot hydrothermal process without any surfactant. The size, crystallography and morphology of the composite were investigated in detail by X- ray diffraction (XRD) studies, Raman spectroscopy, scanning electron microscopic (SEM), transmission electron microscopic (TEM) studies, UV–Vis spectroscopic analysis and X-ray photoelectron spectroscopic (XPS) analysis. The XRD pattern substantiates the formation of Ce doped ZnO/rGO composite revealing the wurtzite structure of ZnO. The SEM micrograph illustrates flower-like morphology for ZnO/rGO composite which coalesced further after cerium incorporation. Additionally, TEM image illustrated that ZnO hexagons were disoriented from its flower structure in Ce/ZnO/rGO composite. The XPS spectra further reaffirm the formation of cerium doped ZnO/rGO composite. The photoluminescence (PL) spectra confirms that emission occurs in the UV and visible region and several active sub-levels were observed in visible region on deconvolution, due to the incorporation of cerium. Antibacterial activity towards B. subtills and V. harveyi affirmed that the incorporation of Ce in ZnO/rGO composite leads to an improved antibacterial activity.     

Electrochemical performance of polydopamine modified PANI/rGO composites: Dependency on preparation sequence

Compounding polyaniline (PANI) and reduced graphite oxide (rGO) is a fascinating cost-effective way to combine the high energy density of faradic material and high power density of carbonaceous material. In this study, in-situ polymerization of dopamine was used to reduce graphite oxide and to modify the rGO product with polydopamine (PDA) simultaneously. This modification prevented restacking of rGO, and enhanced the interactions between PANI and rGO. The partial reduction of GO during the polymerization of dopamine was proven by X-ray diffraction, Fourier transform infrared attenuated total reflectance, and UV–vis spectroscopy. Surprisingly, the electrochemical performance of the composites depends strongly on the preparation sequence. PANI/(rGO-PDA) composites obtained by the synthesis of PANI in the presence of rGO-PDA show better electrochemical performance than (PANI/rGO)-PDA composites, which were produced by polymerizing dopamine in the presence of PANI/GO composite. At a given scan rate of 20 mV s⁻¹, the highest specific capacity of PANI/(rGO-PDA) composites was 230.7 F g⁻¹, which was higher than those of all (PANI/rGO)-PDA composites. This phenomenon is tightly related to the differences in morphologies, conductivities and specific surface areas of the two types of composites.     

Design and Characterization of Chiral and Thermally Stable Nanostructure Poly(amide-imide)s Containing Different Trimellitylimido-Amino Acid-Based Diacids and 4,4′-Methylenebis(3-chloro-2,6-diethylaniline) Units

In this study new chiral nanostructure poly(amide-imide)s (PAI)s were synthesized via direct polycondensation of different trimellitylimido-amino acid-based diacids and 4,4′-methylenebis(3-chloro-2,6-diethylaniline), using tetra-n-butylammonium bromide and triphenyl phosphite as a green media. The formation of these nanostructure PAIs was confirmed by ¹H-NMR, Fourier transform infrared spectroscopy, specific rotation, elemental analysis, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and thermo gravimetric analysis techniques. The FE-SEM micrographs and XRD patterns showed that, the obtained PAIs are nanostructured with different shapes and noncrystalline polymers.     

Thiourea assisted one-pot easy synthesis of CdS/rGO composite by the wet chemical method: Structural,optical, and photocatalytic properties

We report on the synthesis of CdS/reduced graphene oxide (rGO) composite by a wet chemical method. Thiourea was used both as a sulfur source and as a reducing agent to convert graphene oxide to rGO. The structural and morphological confirmation for the reduction of graphene oxide and the formation of the CdS/rGO composite was demonstrated by X-ray diffractometry, Raman spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy analyses. Photoluminescence spectra of the composite exhibited a more efficient luminescence quenching in comparison with pure CdS nanoparticles. The composite demonstrated 99% photodegradation of methyl orange under UV irradiation, which is much superior than the photodegradation of methyl orange under similar conditions exhibited by CdS nanoparticles (72%).     

Mechanical properties and biomedical applications of a nanotube hydroxyapatite-reduced graphene oxide composite

As a result of the growing interest in the biological and mechanical performance of hydroxyapatite (HA)–graphene nano-sheets (GNs) composite systems, reduced graphene oxide (rGO) reinforced hydroxyapatite nano-tube (nHA) composites were synthesized in situ using a simple hydrothermal method in a mixed solvent system of ethylene glycol (EG), N,N-dimethylformamide (DMF) and water, without using any of the typical reducing agents. The consolidation process was performed by hot isostatic pressing (HIP) at 1150 °C and 160 MPa. The composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy, enabling confirmation of the synthesis and reduction of the nHA and rGO, respectively. The structure of the synthesized powder and cell attachment on the sintered sample was confirmed by field emission scanning electron microscopy (FESEM). The effects of the rGO on the mechanical properties and the in vitro biocompatibility of the nHA based ceramic composites were investigated. The elastic modulus and fracture toughness of the sintered samples increased with the increase of the rGO content when compared to the pure nHA by 86% and 40%, respectively. Cell culture and viability test results showed that the addition of the rGO promotes osteoblast adhesion and proliferation, thereby increasing the biocompatibility of the nHA–rGO composite.     

Effects of Nickel Oxide (NiO) nanoparticles on the performance characteristics of the jatropha oil based alkyd and epoxy blends

Plant oil based alkyd resin was prepared from jatropha oil and blended with epoxy resin. Subsequently, alkyd/epoxy/NiO nanocomposites with different wt % of NiO nanoparticles have been prepared by mechanical mixing of the designed components. The structure, morphology, and performance characteristics of the nanocomposites were studied by UV‐visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and universal testing machine (UTM). The alkyd/epoxy/NiO nanocomposites showed the gradual increase in thermal stability with increasing NiO content. With 3 wt % NiO content the tensile strength of the nanocomposite increased by 19 MPa (more than twofold) when compared with the pristine polymer. Limiting oxygen index (LOI) value of the nanocomposites indicate that the incorporation of NiO nanoparticles even in 1 wt % can greatly improves the flame retardant property of the nanocomposites. This study confirms the strong influence of NiO nanoparticles on the thermal, mechanical, and flame retardant properties of the alkyd/epoxy/NiO nanocomposites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41490.     

Photochemical modification and functionalization of carbon surfaces with fluorine moieties

The photolysis of perfluoroazooctane in the presence of carbon materials, such as diamond powder, films, diamond-like carbon films, nanodiamond films and single-walled carbon nanotubes, led to the chemical modification of their surface by the introduction of perfluorooctyl functional groups, which was confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ionization mass spectrometry, Raman spectroscopy and mass spectroscopy measurements. The carbon materials modified with fluorine moieties exhibited a reduced friction coefficient and a reduction of their surface energy, evaluated by the contact angle with water, compared with those of pristine carbon materials.     

Fabrication and tribological properties of a multiply-alkylated cyclopentane/reduced graphene oxide composite ultrathin film

A composite thin film composed of multiply-alkylated cyclopentane (MAC) and reduced graphene oxide (rGO) is prepared on a silicon substrate. The rGO sheets were covalently assembled onto a silicon surface by mutilayer deposition. Meanwhile, MAC was synthesized as a hydrocarbon lubricant. The chemical composition, structure and morphology of the film were characterized utilizing the measurement tool of Raman spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy and film thickness with ellipsometric method, and by the means of high resolution transmission electron microscopy and atomic force microscopic analysis. Results show that the MAC/rGO composite thin films possess good load-carrying capabilities, adhesion resistance and anti-wear performance. This strategy can be applied to many other surfaces, such as metals, glass and semiconductors, by simply changing rGO assembly.     

Influence of aminosilane‐functionalized carbon nanotubes on the rheometric,mechanical, electrical and thermal degradation properties of epoxidized natural rubber nanocomposites

We describe the preparation, characterization and physical properties of multiwalled carbon nanotube (MWCNT)‐filled epoxidized natural rubber (ENR) composites. To ensure better dispersion in the elastomer matrix, the MWCNTs were initially subjected to aminopropyltriethoxysilane (APS) treatment to bind amine functional groups (?NH₂) on the nanotube surface. Successful grafting of APS on the MWCNT surface through Si–O–C linkages was confirmed using Fourier transform infrared spectroscopy. Grafting of APS on the MWCNT surface was further corroborated using elemental analysis. ENR nanocomposites with various filler loadings were prepared by melt compounding to generate pristine and APS‐modified MWCNT‐filled elastomeric systems. Furthermore, we determined the effects of various filler loadings on the rheometric, mechanical, electrical and thermal degradation properties of the resultant composite materials. Rheometric cure characterization revealed that the torque difference increased with pristine MWCNT loading compared to the gum system, and this effect was more pronounced when silane‐functionalized MWCNTs were loaded, indicating that this effect was due to an increase in polymer–carbon nanotube interactions in the MWCNT‐loaded materials. Loading of silane‐functionalized MWCNTs in the ENR matrix resulted in a significant improvement in the mechanical, electrical and thermal degradation properties of the composite materials, when compared to gum or pristine MWCNT‐loaded materials.© 2013 Society of Chemical Industry     

Unusual functionalization of reduced graphene oxide for excellent chemical surface-enhanced Raman scattering by coupling with ZnO

A low-cost noble metal-free substrate comprised of annealed graphene oxide (GO)/ZnO composites is prepared to demonstrate an efficient chemical surface-enhanced Raman scattering effect. A high enhancement factor of about 10⁴, better than those reported for reduced GO (rGO)/Au and GO/Ag composites, is mainly attributed to the unusually abundant oxygen-containing groups generated on surface of rGO by coupling with ZnO nanoparticles at moderate temperature. High-resolution transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy are employed to examine the evolution of ZnO as well as reduction and functionalization of GO after different heat treatments.     

Mechanical,thermal conductive,and dielectric properties of fluoroelastomer/reduced graphene oxide composites in situ prepared by solvent thermal reduction

Fluoroelastomer (FKM)/reduced graphene oxide (rGO) composites are in situ prepared by solvent thermal reduction method in N,N‐dimethylformamide (DMF) solution. The reduction of graphene oxide (GO) is characterized by X‐Ray photoelectron (XPS), ultraviolet–visible (UV–vis), and Fourier transform infrared (FTIR) spectra. GO and rGO are both efficient fillers to improve the mechanical properties of FKM. The dispersibility of rGO is improved after solvent thermal reduction which is confirmed by scanning electron micrograph (SEM) and X‐ray diffraction (XRD). The homogenous suspension of FKM/rGO composites in DMF can stay stable for more than a month. The dielectric permittivity of FKM/rGO (5 phr) is 26.4 at the frequency of 10⁻¹ Hz, higher than the pure FKM (8.1). The thermal conductivity of rGO/FKM composites increases. POLYM. COMPOS., 35:1779–1785, 2014. © 2013 Society of Plastics Engineers     

Semiconductive poly[N1,N4‐bis(thiophen‐2‐ylmethylene)benzene‐1,4‐diamine]‐nickel oxide nanocomposite based ethanol sensor

This study aims to use the conductivity of a synthetic polymer as the sensing probe for ethanol. In order to enhance the sensitivity of the sensor, a composite of the polymer and nickel oxide (NiO) nanoparticles was formed as it improved the conductivity. This composite exhibited 100 times more conductivity than the neat polymer. The semiconductive nanocomposite of poly [N¹,N⁴‐bis(thiophen‐2‐ylmethylene)benzene‐1,4‐diamine]‐nickel oxide (PBTMBDA‐NiO) was prepared by in situ chemical oxidative polymerization. The monomer was N¹,N⁴‐bis(thiophen‐2‐ylmethylene)benzene‐1,4‐diamine (BTMBDA). The monomer (BTMBDA), polymer (PBTMBDA), and NiO nanoparticles used in this study were synthesized. The monomer was prepared by refluxing together 2‐thiophene carboxaldehyde, benzene‐1,4‐diamine, and few drops of glacial acetic acid in ethanol medium for 3 h. The polymer, PBTMBDA, was formed by the chemical oxidative polymerization of BTMBDA in chloroform by FeCl₃. NiO nanoparticles were prepared by slow addition of aqueous ammonia to anhydrous nickel chloride at room temperature (28 ± 2 °C), and at a pH of 8 under constant stirring condition. The composite was formed by in situ chemical oxidative polymerization of BTMBDA in chloroform by FeCl₃ in the presence of the dispersed NiO nanoparticles. The molecular structure of BTMBDA and PBTMBDA were confirmed by nuclear magnetic resonance (NMR) (¹H, ¹³C, and Dept‐90°), Fourier transform infrared spectroscopy, and ultraviolet (UV)–visible spectroscopy. The PBTMBDA and PBTMBDA‐NiO nanocomposite were characterized by X‐ray diffraction, thermogravimetric analysis, field emission scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy analysis. The results of characterization studies indicate the strong interaction between PBTMBDA and NiO in the nanocomposite. The broadness of ¹H NMR peaks in PBTMBDA was due to the increased number of monomer units. The disappearance of the peak of α‐hydrogens on thiophene confirms the polymerization involving the fifth position of thiophene part of BTMBDA. The Fourier transform infrared spectroscopy spectra revealed that position of the characteristic peaks of the functional groups in the monomer shifted toward lower wave numbers in PBTMBDA and PBTMBDA‐NiO nanocomposite. This shifting confirms the presence of extended conjugation along the polymer backbone. Electronic spectra of these compounds showed three absorption bands corresponding to π→π*, n→π* and n→π* transitions of π electron of carbon, lone pair electrons of S, and lone pair electrons of N (imine) groups, respectively. From the Tafel plot, the exchange current density evaluated for the BTMBDA and PBTMBDA are 0.2815 × 10⁻⁸ and 1.1508 × 10⁻⁸ A cm⁻², respectively. PBTMBDA is evaluated to be a better electrode material than the BTMBDA. The X‐ray diffraction plots showed that the characteristic peak of NiO in PBTMBDA‐NiO nanocomposite suggested successful incorporation of NiO in PBTMBDA‐NiO nanocomposite. The thermogravimetric analysis revealed the improved thermal stability of the composite. Field emission scanning electron microscopy and energy‐dispersive X‐ray spectroscopy analysis confirmed the presence of the NiO in the composite. Incorporation of nickel oxide nanoparticles improved the electrical conductivity and stability of PBTMBDA. The conductivity of the polymer was found to be of the order of 10⁻⁵ S cm⁻¹ while that of the composite was of the order of 10⁻³ S cm⁻¹. The nanocomposite was found to be thermally more stable than PBTMBDA and exhibited better direct‐current electrical conductivity and isothermal stability than the PBTMBDA as revealed by the four‐probe study. The electrical conductivity as inferred from the four‐probe method was used as the parameter to study the isothermal stability of the composite. The PBTMBDA‐NiO nanocomposite based vapor sensor was constructed for the sensing of ethanol vapor in commercial ethanol and real samples (alcoholic drinks: Beer, Wine, Brandy, Vodka, Whisky, and Rum) It was observed that on exposure to ethanol vapor at ambient temperature, the electrical resistivity of the nanocomposite increased indicating suppression of charge carriers. The interaction of ethanol vapor with PBTMBDA in PBTMBDA‐NiO nanocomposite was confirmed by IR spectral technique. The change in the structure of the PBTMBDA on interaction with ethanol was highlighted by the changes in the infrared spectrum. The conductivity of the polymer was explained using the structure‐activity relationship of the monomer evaluated using Gaussian 09 software. This study also analyzed the total electron density with electrostatic potential of the monomer and its correlation with chemical reactivity in order to explain the ethanol vapor sensing‐property of the nanocomposite. A new method of ethanol vapor sensing by a conducting polymer composite is hereby reported. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45918.     

Sorption of Cu(II) Ions from Aqueous Solution with Synthesized B-Doped Heptazine-Based g-C/N/H Polymers

In this study, boron doped heptazine-based g-C/N/H polymers (B-doped heptazine-based g-C/N/H polymers) were synthesized by the pyrolysis process of the mixture of low cost H₃BO₃ and melamine. X-ray power diffractometer (XRD) and Fourier transform infrared spectroscopy (FT-IR) were applied to characterize the successful doping of B atoms into the nanostructure of the graphic-C₃N₄ (heptazine-based g-C/N/H polymers). The synthesized material was conducted to investigate the sorption capacity for Cu(II) ions from aqueous solution and the sorption conditions including the doped amount, the solution pH, the contact time, and initial concentration were optimized. The results indicated that the sorption process was dependent on solution pH and the optimum pH was from 3.0 to 6.0. The kinetics was well evaluated by pseudo-second-order which indicated that the main rate-determining step was controlled by the chemical sorption process. The maximum sorption capacity calculated from Langmuir model amounted to 149.3 mg g^?1 with the initial concentration range from 80 ～ 800 mg L^?1. So, B-doped heptazine-based g-C/N/H polymers have the potential application as a low cost adsorbent for high concentration Cu(II) ions in aqueous solution.     

Battery-like behavior of Ni-ceria based systems: Synthesis,surface defects and electrochemical assessment

NiO, CeO₂ and respective composites are extensively used in energy storage devices due to mostly their high electrochemical activity. However, the assessment of battery-like behavior of Ni-ceria based systems comprising (Ni or Gd)-doped ceria combined with NiO seems to be neglected in the literature. In this work, NiO and ceria-based solid solutions composite powders were obtained by a co-precipitation synthesis method. The structure and particle size of the calcined powders were investigated by X-ray diffractometry (XRD) and field emission scanning electron microscopy (FESEM), respectively. Oxidative states of composites were inspected by X-ray photoelectron spectroscopy (XPS). The electrochemical performance of powders was evaluated by cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy. Refinement of the XRD patterns showed that powders have nanosized crystallites and mean size of particles within 20 – 70?nm were revealed by FESEM. The improved specific capacity of the NiO-CeO₂ electrode material (about 2.5 times higher than that of NiO-CGO at 5?mV?s^?1) is due to an increase in Faradic reactions taken place on its surface with a higher fraction of defects (namely Ni³⁺, Ce³⁺ and oxygen vacancies), as determined by XPS. The superior electrochemical performance of the NiO-CeO₂ electrode is also confirmed by electrochemical impedance spectroscopy.     

Facile synthesis,characterization and material properties of a novel poly(vinyl cinnamate)/ nickel oxide nanocomposite

A poly(vinyl cinnamate) (PVCin) composite was synthesized by a simple one step in situ polymerization of vinyl cinnamate with nickel oxide (NiO) nanoparticles. The structural, morphological and thermal properties of the nanocomposite were characterized using Fourier transform (FT)‐Raman, FT infrared (FTIR) and UV spectroscopies, X‐ray diffraction (XRD), high‐resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), differential scanning calorimetry and vibrating sample magnetometry (VSM) measurements. FT‐Raman, FTIR and UV spectroscopy results revealed the characteristic absorption and shifts of peaks of the polymer matrix, the shifts being attributed to the interaction of NiO nanoparticles with the polymer chains. The structural and morphological analysis using XRD, HRTEM and FESEM showed the uniform arrangement of nanoparticles within the polymer chains. VSM showed the ferromagnetic nature of the composite with an increasing saturation of magnetism. The glass transition temperature (T_g) of the composite was higher than that of pure PVCin and T_g of the composite increased with increasing nanoparticle content. The electrical resistivity of the nanocomposite was studied from AC and DC conductivity measurements. AC and dielectric properties were markedly enhanced in the whole range of frequency due to the presence of NiO nanoparticles. DC conductivity of the nanocomposite was much higher than that of PVCin and the conductivity of the nanocomposite increased with increasing content of NiO nanoparticles. © 2016 Society of Chemical Industry