High-resolution Transmission Electron Microscopy Techniques Research Articles

Nanomolar detection of L-cysteine and Cu2+ ions based on Trehalose capped silver nanoparticles

This work describes the solvent-free solid-state synthesis of Trehalose capped silver nanoparticles (Th-AgNPs) and its L-Cysteine and Cu2+ ions sensor application. We have prepared Th-AgNPs by the solid-state method within 5 min by simple grinding. During the synthesis of AgNPs, trehalose in alkaline medium acts as reducing as well as capping agent. The Th-AgNPs were well characterized by Ultraviolet–visible (UV–vis) spectroscopy, Fourier Transform Infrared (FT-IR) Spectroscopy, X-Ray Diffraction (XRD) and High-Resolution Transmission Electron Microscopy (HR-TEM) techniques. FT-IR spectral studies confirmed that Trehalose –OH, groups were adsorbed on the surface of AgNPs. XRD pattern of Th-AgNPs revealed that synthesized Th-AgNPs presented good crystalline nature and face-centred cubic structure. The particles size was calculated to be 9.312 ± 0.23 nm by HR-TEM image. Interestingly, after the addition of L-Cysteine into Th-AgNPs, the particles are aggregated, followed by the decreases in SPR band absorbance at 400 nm was observed and a new peak appears at 550 nm. In contrast, the addition of Cu2+ ions led to an increase of the SPR band at 400 nm and 550 nm and the color of the solution changed to yellowish red. The reverted SPR peak shift and color changes are expected due to the deaggregation of nanoparticles, which was further confirmed by HR-TEM. Based on the changes in SPR band, the concentration of L-Cysteine and Cu2+ ions were sensed, and the limit of detection (LOD) was found to be 1.48 and 1.92 nM (LOD = 3S/m), respectively. 750-fold (2.94 × 10−4 M) of common amino acids and 300-fold (4.89 × 10−4 M) of common metal ions did not interfere with the specific detection of 0.33 μM of L-Cysteine and 1.63 μM of Cu2+ ions. We have successfully applied this system for the detection of L-Cysteine and Cu2+ ions in different environmental, biological and drug samples. Importantly, we have prepared a paper-based kit for on-site monitoring of L-Cysteine and Cu2+ ions. This new synthesis protocol and the developed paper-based kit will provide an insight in the field of material science, nanotechnology and biosensor applications.

Polymer-Based Graphene Derivatives and Microwave-Assisted Silver Nanoparticles Decoration as a Potential Antibacterial Agent.

Nanocomposites obtained by the decoration of graphene-based materials with silver nanoparticles (AgNPs) have received increasing attention owing to their antimicrobial activity. However, the complex synthetic methods for their preparation have limited practical applications. This study aims to synthesize novel NanoHybrid Systems based on graphene, polymer, and AgNPs (namely, NanoHy-GPS) through an easy microwave irradiation approach free of reductants and surfactants. The polymer plays a crucial role, as it assures the coating layer/substrate compatibility making the platform easily adaptable for a specific substrate. AgNPs’ loading (from 5% to 87%) can be tuned by the amount of Silver salt used during the microwave-assisted reaction, obtaining spherical AgNPs with average sizes of 5–12 nm homogeneously distributed on a polymer-graphene nanosystem. Interestingly, microwave irradiation partially restored the graphene sp2 network without damage of ester bonds. The structure, morphology, and chemical composition of NanoHy-GPS and its subunits were characterized by means of UV-vis spectroscopy, thermal analysis, differential light scattering (DLS), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray analysis (EDX), Atomic Force Microscopy (AFM), and High-Resolution Transmission Electron Microscopy (HRTEM) techniques. A preliminary qualitative empirical assay against the typical bacterial load on common hand-contacted surfaces has been performed to assess the antibacterial properties of NanoHy-GPS, evidencing a significative reduction of bacterial colonies spreading.

Effect of Mg and Cu doping on structural, optical, electronic, and thermal properties of ZnS quantum dots

Undoped and 10% Mg or Cu-doped ZnS quantum dots (Zn0.9Mg0.1S and Zn0.9Cu0.1S) were prepared by a simple chemical method at low temperature (300 °C). The effect of doping on structural characteristics was investigated using Rietveld profile method and the high-resolution transmission electron microscope techniques. Differential scanning calorimetry (DSC) scans were recorded in the temperature range 23–600 °C with different heating rates (5 to 30 °C/min). The model-free isoconversional method was applied to explore the effect of doping on the reaction and the growth mechanism of nano-ZnS. Diffuse UV reflectance revealed an increase of the optical energy gap upon doping with Mg, while it decreased as ZnS was doped with Cu. The change in energy gap upon doping was explained using density function theory calculation. The photoluminescence (PL) spectra revealed violet, blue, green colors depended on the composition and excitation wavelength used in the study. The intensity of PL has been increased for doped samples compared with pristine ZnS. Tuning the energy gap of ZnS through doping enable applications for light-harvesting and photocatalytic degradation in the visible region.

Superplastic deformation of Mg\u20139Li\u20132Al\u20130.5Sc alloy after grain refinement by KoBo extrusion and cyclic forging

The quaternary Mg–9Li–2Al–0.5Sc alloy (in wt%) was prepared from pure components. After homogenization, the alloy was subjected to severe plastic deformation by KoBo extrusion and cyclic forging leading to grain refinement in the range of 0.5–2 µm of hexagonal close-packed (HCP) α phase. Deformed alloys showed high ultimate tensile strength near 200 MPa and good elongation in the range 30–40% at room temperature (RT). Large elongations close to 200% were obtained during the tensile test at a temperature of 200 °C. Deformed samples showed the presence of multiple voids confirming grain boundary sliding mechanism of deformation. Twins on {10overline{1}2} planes were identified using electron backscatter diffraction analysis, being in a good agreement with the earlier observation of Mg–Li and Mg–Sc alloys. Intermetallic phases such as cubic MgSc were identified in deformed alloys mostly within HCP α phase, whereas HCP MgSc2 particles were observed within body-centered cubic (BCC) β phase. Intermetallic phases were responsible for RT strengthening of alloys and slightly lower tensile elongation during superplastic deformation. Formation of the HCP α phase was observed within the BCC β phase in tensile deformed alloys. Atomic-level nucleation of HCP phase within the β phase was identified by the use of high-resolution transmission electron microscopy technique.

Strong spin-orbit interactions in a correlated two-dimensional electron system formed in SrTiO3(001) films grown epitaxially on p−Si(001)

We observe strong spin-orbit interactions in a two-dimensional electron system formed on $\mathrm{SrTi}{\mathrm{O}}_{3}(001)$ films grown epitaxially on p-Si(001). High-resolution transmission electron microscopy and related analytical techniques reveal a sharp interface between Si and $\mathrm{SrTi}{\mathrm{O}}_{3}$. Strain mapping analysis shows in-plane strain in $\mathrm{SrTi}{\mathrm{O}}_{3}$ very close to the interface. Analysis of the low temperature magnetoconductance measurements reveals that both quantum interference and electron-electron interactions are important. The contributions of these two quantum phenomena to the temperature and magnetic field dependence of the conductance and Hall effect are separated. The electron system has carrier concentrations larger than ${10}^{14}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}2}$, appears to be confined within \ensuremath{\sim}4 nm, and has an estimated spin-splitting energy \ensuremath{\sim}12 meV.

Structural Evolution in the Quenched Al–Zn–Mg–Fe–Ni Alloy during Severe Plastic Deformation and Annealing

The evolution of the structure and phase composition of the Al–Zn–Mg–Fe–Ni alloy (nikalin) during severe plastic deformation by high pressure torsion and annealing has been investigated using high-resolution TEM techniques. The deformation of the quenched alloy has been found to result in a submicron composite comprising an Al matrix and various fine aluminides. The severe structural refinement takes place along with phase transformations, which dissolve the metastable Al3Zr-phase particles and cause the nanosized strengthening phases Т (Al2Mg3Zn3) and η' (MgZn2) to precipitate from the Al solid solution which has been supersaturated in result of quenching and deformation. Nikalin has been determined to retain its submicrocrystalline state during low-temperature annealing (200°C, 4 h) due to the barrier effect of fine hardening phase particles, fixing grain boundaries. High-temperature heating to 400°C for four hours transfers nikalin to the overaged state, in which it is characterized to consist of a recrystallized matrix with grains 2–3 µm in size, eutectic micron-sized aluminides, and stable Al2Mg3Zn3 and MgZn2-phase particles with sizes of no more or equal to 500 nm.

Anisotropic morphology, formation mechanisms, and fluorescence properties of zirconia nanocrystals

ZrO2 nanocrystals with spheres and elongated platelets were systemically prepared through a simple hydrothermal method by the use of ZrOCl2·8H2O and CH3COOK as raw materials. The anisotropic morphology and formation mechanism of the monoclinic and/or tetragonal ZrO2 were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, and high-resolution transmission electron microscope techniques. The uniform elongated platelets and star-like structures were composed of short nanorods with a diameter of approximately 5 nm and a length of approximately 10 nm. The different morphologies were formed due to the different contents of CH3COO− and Cl− and their synergy. The fluorescence band position and the band shape remained about the same for excitation wavelengths below 290 nm and the different morphologies of the nanocrystals.

Mechanism of CeO2 synthesized by thermal decomposition of Ce-MOF and its performance of benzene catalytic combustion

In this paper, the formation mechanism of mesoporous CeO2 synthesized by thermal decomposition of Ce-MOF and its performance of benzene catalytic combustion, as well as the structure–activity relationship between them were studied in depth. The self-assembly process and physicochemical properties of CeO2 were characterized by thermogravimetry analysis, powder X-ray diffraction, N2 adsorption/desorption, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy techniques. Characterization results show that Ce-MOF is completely decomposed into pure mesoporous CeO2 when the decomposition temperature is higher than 400 °C. At this threshold temperature, CeO2 (400) has the largest specific surface area and pore volume of 114 m2/g and 0.152 cm3/g, respectively. CeO2 (400) exhibits very high catalytic activity for benzene combustion, which can completely catalyze the degradation of benzene at 260 °C. Meanwhile, the mesoporous CeO2 (400) supported Pt nanocrystalline catalysts were prepared by high temperature solution-phase reduction method. Pt/CeO2 (400) can completely degrade benzene at about 200 °C and represents high durability and good water-resistance for benzene combustion during 100 h of continuous reaction.

Direct Observation of Li Migration into V5S8: Order to Antisite Disorder Intercalation Followed by the Topotactic-Based Conversion Reaction.

Two-dimensional transition-metal dichalcogenides hold great potential in rechargeable lithium-ion batteries. Their electrochemical properties are closely related to the structural evolutions during lithium-ion migration. Understanding these migration/reaction mechanisms is important to help improve battery performance. Herein, we report the real-time and atomic-scale observation of phase transitions during the lithiation and delithiation for V5S8 via in situ electron diffraction and high-resolution transmission electron microscopy techniques. We find that the phase transformation proceeds via a sequence of order to antisite disorder intercalation and topotactic-based conversion reaction. During the intercalation reaction, the lithium ion destroys the orderings of the interstitial V with the formation of Li/V antisite. Such a reaction is found to be reversible, i.e., the extraction of lithium from LixV5S8 leads to the recovery of V orderings. The conversion reaction involves heterogeneous nucleation of Li2S with 3-20 nm nanodomains, which maintain the crystallographic integrity with LixV5S8. These findings elucidate the complex interactions between the lithium ion and host V5S8 during ionic migration in solids, which should be helpful in understanding the relationship between phase transformation kinetics and battery performance.

ZnWO4/SnO2@r-GO nanocomposite as an anode material for high capacity lithium ion battery

Lithium ion battery (LIB) is widely used energy storage device. Herein, we report the preparation of ZnWO4/SnO2 nanocomposite and ZnWO4/SnO2@r-GO nanocomposite via solvothermal method. The structural, elemental and morphological properties of the prepared samples are characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), high-resolution transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller (BET) measurements, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques. The prepared samples are tested as an anode for LIB. The ZnWO4/SnO2 (5%) nanocomposite delivers initial discharge capacity of 882 mAh g−1 at a current density of 100 mA g−1, while, the specific capacity increases with the increase of SnO2 upto 10% tested in present case. Further, ZnWO4/SnO2@r-GO nanocomposite exhibits a discharge capacity of 1486 mAh g−1 which is higher than that of ZnWO4/SnO2 nanocomposite. In addition, after 500 cycles ZnWO4/SnO2@r-GO nanocomposite exhibits 89.8% cycle life and 98% of discharge capacity retention. These results indicate that, ZnWO4/SnO2@r-GO nanocomposite is a promising anode material for LIB.

Hydrothermal synthesis of Mn3O4 nanoparticles by evaluation of pH effect on particle Size formation and its antibacterial activity

In this work, we report a simple, controlled strategy to prepare manganese oxide nanoparticles (Mn3O4 NPs) using one-step, eco-friendly hydrothermal synthesis method. The effect of Mn3O4 NPs size using different levels of pH 8, pH 10 and pH 12 at short processing time and low temperature was investigated. The prepared Mn3O4 NPs structure and surface morphology analyses were characterised by using different techniques such as x-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM), and high resolution transmission electron microscopy (HR-TEM). The elemental analysis was confirmed from EDAX spectra. The XRD patterns of Mn3O4 NPs have tetragonal hausmannite structure with a same phase. The surface morphology of Mn3O4 NPs was in unique spherical shape, which was confirmed from both SEM and HR-TEM techniques. The Mn3O4 NPs were prepared at different pH levels, which showed the impact on increase of particle size. After that the antibacterial activity of Mn3O4 NPs against gram-positive and gram-negative bacteria was performed by disk diffusion method. The obtained results of synthesised Mn3O4 NPs have exhibited better antibacterial activity against gram-negative bacteria like Klebsiella pneumoniae (MTCC 532) and Pseudomonas aeruginosa (MTCC 1688) than two remaining microorganisms like Bacillus subtilis (MTCC 10619) and Salmonella ebony (MTCC 3384).

Designing a non-hazardous nano-carrier based on graphene oxide@Polyaniline-Praseodymium (III) for fabrication of the Active/Passive anti-corrosion coating

In this work, graphene oxide (GO) based nano-platforms were applied as a non-hazardous solid container with high encapsulating capacity and controllable release activity of eco-friendly inhibitor. For the first time, the adsorption and release properties of the praseodymium cations (Pr3+) on GO nanosheets functionalized with polyaniline (PANI) were investigated. The Pr3+ cations adsorption/desorption capacity of GOPANI nano-sheets was assessed by Inductively Coupled Plasma (ICP), X-ray photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscopy (FE-SEM), and High-resolution transmission electron microscopy (HR-TEM) techniques. The obtained results proved that the container modified with Pr3+ cations at pH of 7, 600 ppm of adsorpt, and 1 mg/cc of adsorbent dosage provided the highest capacity of inhibitors adsorption/release rates. The adsorption capacity of the GO-PANIs reached more than 500 mg/g. Also, the modified carrier desorbed about 70 % of loaded Pr3+ cations in the corrosion simulated condition. The self-healing anti-corrosion ability of the constructed containers in an organic-inorganic hybrid coating (OIHC) was shown by electrochemical analyses results. The resistance of coating with the loaded carriers has increased about 1 order of magnitude in comparison with the neat silane. Moreover, the scratched coatings containing the inhibitor loaded GO-PANIs showed extraordinary total resistance of about 25 Kohm. cm2.

Influence of alloying ratio in tailoring the structural and optical properties of (1 − x)CdS–xCuS nanocomposite

Nanocomposites of CdS@CuS heterostructures were synthesized applying a simple chemical procedure. The structural characteristics of resulting nanocomposites (1 − x)CdS–xCuS (x = 0, 0.3, 0.5, 0.7 and 1) samples were inferred applying synchrotron X-ray diffraction (XRD), Fourier transform infrared (FTIR) and high-resolution transmission electron microscope techniques. The optical characteristics were deduced from the UV–Vis and photoluminescence (PL) spectroscopy techniques. XRD phase identification revealed CuS having the hexagonal phase P 63/m m c, while CdS in two phases: cubic major phase $$ F \bar{4} 3 m $$ and hexagonal minor phase P 63 m c. The phase percentage, the crystallite size, the lattice parameters and the ions coordinates of each phase are traced as a function of the alloying parameter (x). FTIR analysis revealed a change in the transmittance intensity of the vibration bands upon changing CdS/CuS ration in the nanocomposites matrix. UV–Vis absorption spectra were affected greatly by the ratio of CdS to CuS in the different composites. All composites materials exhibited two energy gaps lower than parent compounds. The PL emission of CdS sample is broader than CuS sample. The PL spectra of CdS@CuS nanocomposites samples revealed a broad emission with a redshift depending on the ratio between CdS and CuS in the matrix. All samples emitted UV, violet and blue colors, while CuS sample reveals UV and violet colors. The obtained properties of CdS@CuS nanocomposites, by changing the composition ratio, make them good candidates for enhanced visible light photocatalytic activity and solar energy applications.

TEM Nanostructural Investigation of Ag-Conductive Filaments in Polycrystalline ZnO-Based Resistive Switching Devices.

Memristive devices based on a resistive switching mechanism are considered very promising for nonvolatile memory and unconventional computing applications, even though many details of the switching mechanisms are not yet fully understood. Here, we report a nanostructural study by means of high-resolution transmission electron microscopy and spectroscopy techniques of a Ag/ZnO/Pt memristive device. To ease the localization of the filament position for its characterization, we propose to use the guiding effect of regular perturbation arrays obtained by FIB technology to assist the filament formation. HRTEM and EDX were used to identify the composition and crystalline structure of the so-obtained conductive filaments and surrounding regions. It was determined that the conducting paths are composed mainly of monocrystalline Ag, which remains polycrystalline in some circumstances, including the zone where the switching occurs and at secondary filaments created at the grain boundaries of the polycrystalline ZnO matrix. We also observed that the ZnO matrix shows a degraded quality in the switching zone, while it remains unaltered in the rest of the memristive device.

SrCoxZrxFe12−2xO19 and SrNixZrxFe12−2xO19 hexaferrites: A Comparison Study of AC Susceptibility, FC-ZFC and hyperfine interactions

This study compares the AC susceptibility, FC-ZFC and hyperfine interactions of Sr(CoxZrx)Fe12−2xO19 and Sr(NixZrx)Fe12−2xO19 hexaferrites (HFs) manufactured via ultrasonic route. The formation of M-type hexaferrites have been confirmed by X-ray powder diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR) and high-resolution transmission electron microscopy (HR-TEM) techniques. Scanning electron microscopy (SEM) presented the hexagonal-platelet morphology of products. The variation in isomer shift, line width, quadrupole splitting and hyperfine magnetic field values of them have been governed by 57Fe Mössbauer spectroscopy which showed that Co2+ and Zr4+ ions located at generally octahedral and 2b sites, while Ni2+ and Zr4+ ions located at octahedral 12k and 4f2 sites. Measurements of magnetization versus temperature (M-T) and AC susceptibility versus temperature were carried out. The various synthesized HFs displayed ferrimagnetic behavior in the temperature interval of 10–325 K. Super-spin glass-like behavior was noticed at lower temperatures. Neel-Arrhenius and Vogel-Fulcher models were used to explore the experimental AC susceptibility. It was showed that a lower Co-Zr substitution content leads to strengthen the magnetic exchange interactions, however even low Ni-Zr substitution content provoke a reduction in magnetic exchange interactions.

Synergetic effect between MoS2 and N, S- doped reduced graphene oxide supported palladium nanoparticles for hydrogen evolution reaction

An active, stable, and relatively low-cost electrocatalyst is crucial in the sustainable production of hydrogen through water electrolysis. In this work, the electrocatalytic activity of Pd supported on MoS2 and nitrogen, sulfur-doped reduced graphene oxide (Pd/MoS2/N,S-rGO) was investigated by two-step hydrothermal method followed by chemical reduction of Pd using sodium borohydride (NaBH4). The Structural and morphological structure of the sample was studied by using X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscope (HRTEM) techniques. The electrochemical hydrogen evolution (HER) performance of the electrocatalyst was studied by using Linear Sweep Voltammetry (LSV), Electrochemical Impedance Spectroscopy (EIS), and Chronoamperometry (CA). The result shows a structural transformation in the MoS2 phase after the incorporation of Pd nanoparticles. The synthesized (Pd/MoS2/N,S-rGO) electrocatalyst shows a significantly lower overpotential of −42 mV vs. RHE at 10 mA/cm2 and Tafel slope value of 38 mV.dec−1. This study demonstrated with low palladium loading, the high activity of the electrocatalyst could have resulted from the cumulative effect of 1T MoS2, sulfur vacancy formation, and higher surface area of N,S-rGO.

Ultrathin nickel terephthalate nanosheet three-dimensional aggregates with disordered layers for highly efficient overall urea electrolysis

The controlled synthesis of ultrathin metal-organic framework (MOF) nanosheets and the rational design of three-dimensional (3D) aggregates of these nanosheets are vital for electrochemical applications. Herein, ultrathin nickel terephthalate nanosheet 3D aggregates were synthesized by a facile one-pot hydrothermal method and employed as electrocatalysts for overall urea electrolysis. Surprisingly, the thickness of the nanosheets could be controlled by varying the synthesis time. A low-dose high-resolution transmission electron microscopy (TEM) technique with spherical aberration corrected TEM was utilized to visualize the crystalline structures of the ultrathin MOF nanosheets. Interestingly, ~5 nm thick disordered layers were observed at the edges of the ultrathin nanosheets, plausibly induced by vacancies that could not be identified with conventional TEM. The 3D aggregates of the ultrathin nanosheets with disordered layers required an ultralow potential of 1.381 V for urea oxidation with a current density of 10 mA cm−2, which is 186 mV lower than that for the oxygen evolution reaction, and a potential of 1.52 V for overall urea electrolysis, with outstanding long-term durability. The amazing catalytic properties may be attributed to the adequate unsaturated coordination of nickel on the surface of the disordered layers, which guarantees numerous active sites; these results are consistent with the high-resolution TEM observations.

Ultrafine lamellar structure AM60B magnesium alloy sheet prepared by high strain rate rolling

The rolled sheet was successfully prepared for the as-cast AM60B magnesium alloy by using the high strain rate rolling (HSRR) in the temperature range of 310 °C – 370 °C. An ultrafine lamellar structure consisting of small angle grain boundaries was developed in the HSRRed sheet by the detwinning of high-density twins. The ultrafine lamellar structure was characterized by means of the high-resolution transmission electron microscopy technique, and the effect of temperature on the detwinning was analyzed. Furthermore, the morphological difference of the ultrafine lamellar structure and its effect on the mechanical properties of the rolled sheet were investigated. The results show that the dislocation motion, cross twinning, dynamic recovery and dynamic recrystallization have multiple interactions with the detwinning behavior in different modes. And the degree of detwinning and the post-rolling microstructure are greatly affected by the interaction. Dynamic precipitation of the second phase is induced by the HSRR process at 370 °C. Nano particles precipitate along twin grain boundaries and form the ‘precipitation band’. However, the detwinning is not affected by the ‘precipitation band’. In addition, it is also revealed from the results that a uniform and fine fully-lamellar structure is developed as the HSRR process is conducted at a medium temperature of 340 °C. Meanwhile, the alloy rolled at 340 °C has relatively optimal mechanical properties, and the strength and ductility are well balanced.

Structural properties of ZnSe/InSe/ZnSe heterostructures grown by molecular beam epitaxy on GaAs(001) substrates

The paper reports on molecular beam epitaxy of ZnSe/InSe/ZnSe quantum well (QW) heterostructures grown on GaAs(001) substrates as well as studies of their structural properties. The structures were characterized by reflection high energy electron diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy techniques. The evolution of surface morphology of QW heterostructures as a function of the InSe thickness has been studied. The quasi van der Waals growth of ZnSe on the InSe(0001) surface has been demonstrated, with the ZnSe(111) plane being oriented parallel to the (0001) plane of InSe because of a small lattice mismatch between InSe and ZnSe(111).

Hierarchical nano Fe(0)@FeS doped cellulose nanofibres derived from agrowaste – Potential bionanocomposite for treatment of organic dyes

Biological macromolecule namely cellulose nanofiber was synthesized from agrowaste sugarcane bagasse. Further, hierarchical nano Fe(0) – FeS was anchored on cellulose nanofibers to obtain CNF-Fe(0)@FeS and it was characterized by various spectral techniques. Formation of FeS2 was confirmed by high resolution TEM and XPS techniques. Anchoring on cellulose nano fibers prevented agglomeration of nanocomposite and furthermore, coating of FeS2 helped in the preservation of Fe(0). Thus the prepared nano composite was very effective in the removal of cationic Methylene blue (MB) dye and anionic Congo red (CR) dye with a maximum adsorption capacity of 200.0 and 111.1 mg/g respectively. Both MB and CR dye followed Pseudo second kinetic with regression coefficients >0.98. Especially for MB dye, it was observed that kinetics of adsorption/degradation was very fast and within 3 min, peak at 370 nm disappeared and 70% reduction in intensity was observed at 660 nm. Further FTIR and XPS revealed evidence for the degradation of adsorbed dye molecules. Considering its high adsorption capacity, degradation potential and ease of preparation using agrowaste makes CNF-Fe(0)@FeS a promising sorbent for the treatment industrial dye effluents.