Seed-mediated Hydrothermal Method Research Articles

Enhanced ethanol sensing performance of Cu-doped ZnO nanorods

Cu-doped ZnO (Zn1−xCuxO, x=0.00,0.01,0.02,0.03 and 0.04) nanorods (NRs) were grown on glass substrates by a seed-mediated hydrothermal method for gas sensing applications. The morphological and structural characterizations were performed by x-ray diffraction method (XRD) and scanning electron microscopy equipped with electron dispersive spectroscopy (EDS). Fabricated sensors were tested against H2, NO2, ethanol, acetone, xylene and toluene at different operation temperatures. It was found that Cu doping enhanced the sensor response of ZnO NRs especially towards ethanol. The highest sensor response against the ethanol were obtained with 2% and 3% Cu-doped ZnO NRs. Moreover, Cu-doping allowed us to operate ZnO NRs sensors at lower temperatures. Although pristine ZnO NRs did not show any sensor response at 100 °C, 2% Cu-doped sensors exhibited selective sensor behavior towards ethanol among the other tested gases.

SEED MEDIATED SYNTHESIS OF HEXAGONAL S-DOPED ZnO NANOROD AND ITS PHYSICAL PROPERTIES

Sulfur-doped zinc oxide (S-ZnO) nanorod has been successfully synthesized via the seed-mediated hydrothermal method with different sulfur concentrations (0%, 1%, 2.5%). This research aims to study the influence of the concentration of sulfur on the structure, morphology, and optical properties of ZnO as a promising material in a wide range of applications. Crystal structure, morphology, and optical properties of the samples were characterized using X-Ray Diffraction (XRD), Field Emission Electron Scanning Microscopy (FESEM), and UV-Vis Spectroscopy, respectively. The XRD pattern shows the strongest peak at 2θ = 34.43° for crystal orientation of (002). The crystallinity properties of the S-ZnO sample are higher compared to the ZnO sample. The FESEM images of the 1% S-ZnO sample exhibit the highest nanorod density arrangement. The optical absorbance of the higher sulfur dopant possesses a higher optical absorption peak on the UV-Vis spectrum. The results indicate that S doping to ZnO can alter the structural, morphological, and optical properties of ZnO.

Seed-Mediated Synthesis and Photoelectric Properties of Selenium Doped Zinc Oxide Nanorods

Pristine ZnO and selenium doped ZnO (Se-ZnO) nanorods were successfully synthesized using seed-mediated hydrothermal method. The growth solution of both pure and Se-doped ZnO nanorods employed zinc nitrate hexahydrate (ZNH) and hexamethylenetetramine (HMT) as a precursor and surfactant, respectively. As a dopant source, selenium salt solution was obtained by reacting selenium powder with sodium borohydride at low temperature. The as-prepared pure ZnO and Se-doped ZnO nanorods were characterized using field effect scanning electron microscopy (FESEM), X-ray diffraction (XRD), UV-Visible spectroscopy (UV-Vis), and Photoluminescence (PL) spectroscopy. FESEM images show that the geometric shape of Se-ZnO nanoparticles is nanorods with a hexagonal cross-section. The XRD pattern shows the diffraction peak of the sample at the angles of 2θ: 34.44°, 36.25° and 47.54° which represents the hkl plane of (002), (101) and (102), respectively. The crystalline size calculated from XRD data is found to be in the range of 35-42 nm. The UV-Vis spectrum shows that Se-ZnO nanorods strong absorption peaks appeared in the range of 300-380 nm for all samples. Se doping has slightly altered the band gap energy of pure ZnO nanorods around 0.01 eV. The peak of the photoluminescence spectra of the sample at 470 nm indicates the blue emission band.

THE SYNTHESIS AND CHARACTERIZATION OF ZINC OXIDE THIN FILM DOPING SELENIUM

The selenium-doped ZnO nanomaterial has successfully grown the surface of FTO (Fluorine Tin Oxide) using a seed-mediated hydrothermal method at a temperature of 90°C for 5 hours. In this research, the doping selenium by variation the volume of selenium solution at 0 mL, 0.025 mL dan 0.2 mL. This is an impact on the optical properties and morphology of ZnO nanorods. The samples were characterized using UV-Vis spectroscopy, X-Ray Diffraction and Field Emission Scanning Electron Microscopy (FESEM). The UV-Vis spectra showed that strong absorption occurs in the wavelength range of 300-380 nm. The 0.025 mL Se doped ZnO was the highest absorption compared to other samples. The XRD pattern exhibited five peaks at an angle of 2θ: 31.70 °; 34.4 °; 36.2 °; and 47.5 °. representing the orientation of the crystal planes (100), (002), (101), and (102) of hexagonal lattice. The FESEM images showed that Se doped ZnO with hexagonal face shape. The 0.2 mL Se doped ZnO was the most uniform compared to other samples.

Palladium Role in Growth of ZnO Nanostructure with Plasmonics Layering by Seed Mediated Hydrothermal Method

The electrical and optical properties of nanomaterials depend on their structural form. As an effort to develop an advanced nanomaterial, zinc oxide (ZnO) is interesting to synthesis for many applications such as active material for solar cells and biosensors. This paper provides the role of palladium and plasmonic materials in growing ZnO nanostructure, with a focus on its structural analysis. Nanomaterial ZnO was grown by seed-mediated hydrothermal method with layering by plasmonic materials, i.e. gold (Au) and platinum (Ag). X-ray diffraction analysis shows the presence of three dominant peak angles, i.e 34.43o, 36.32o, and 47.49o corresponding to crystal orientation of (002), (101) and (102), respectively. Palladium (Pd) treatment plus layering by plasmonic materials give a higher size of the nanostructure, but their electric band gaps are decreasing slightly. These findings also supported by high absorbance in UV-vis spectra. Gold layering on the nanomaterial gives a more significant role than platinum which indicated by higher size in diameter and higher absorption of UV-Vis spectra. The average size of pristine ZnO, ZnO:Pd, ZnO:Pd:Ag, and ZnO:Pd:Ag are 44.13, 45.99, 45.28, and 44.81 nm, respectively.

On the durability of Pt coated Ti electrodes for the electro-oxidative dissolution of spent nuclear fuels

ABSTRACTThe main objective of this study is to assess the long-term performance of Pt nanoparticle coated anodised Ti coupons which are used for electrochemical dissolution of spent mixed-oxide nuclear fuels during reprocessing. In this work, electrodes were exposed to a simulated dissolver solution containing a representative fraction of low-activity actinides and fission products in 11.5 N nitric acid in a mock-up of the service dissolver vessel. Platinum nanoparticles were coated onto anodised titanium coupons through a seed-mediated hydrothermal method. The coated coupons were then exposed in the simulated dissolver solution for about 1185 h at 110°C. Morphological and compositional analyses confirmed the presence of metallic Pt nanoparticles on the electrode surface with some localised cracking. The electrochemically active surface area of the Pt-nanoparticle coated anodised titanium coupon after exposure was found to be twice that of polycrystalline platinum thus establishing the durability and efficiency of the coating on the electrode.

MoS2-Modified Curcumin Nanostructures: The Novel Theranostic Hybrid Having Potent Antibacterial and Antibiofilm Activities against Multidrug-Resistant Hypervirulent Klebsiella pneumoniae.

The recent emergence of hypervirulent clinical variants of Klebsiella pneumoniae (hvKP) causing community-acquired, invasive, metastatic, life-threatening infections of lungs, pleura, prostate, bones, joints, kidneys, spleen, muscles, soft-tissues, skin, eyes, central nervous system (CNS) including extrahepatic abscesses, and primary bacteremia even in healthy individuals has posed stern challenges before the existing treatment modalities. There is therefore an urgent need to look for specific and effective therapeutic alternatives against the said bacterial infection or recurrence. A new type of MoS2-modified curcumin nanostructure has been developed and evaluated as a potential alternative for the treatment of multidrug-resistant isolates. The curcumin quantum particles have been fabricated with MoS2 via a seed-mediated hydrothermal method, and the resulting MoS2-modified curcumin nanostructures (MQCs) have been subsequently tested for their antibacterial and antibiofilm properties against hypervirulent multidrug-resistant Klebsiella pneumoniae isolates. In the present study, we found MQCs inhibiting the bacterial growth at a minimal concentration of 0.0156 μg/mL, while complete inhibition of bacterial growth was evinced at concentration 0.125 μg/mL. Besides, we also investigated their biocompatibility both in vitro and in vivo. MQCs were found to be nontoxic to the SiHa cells at a dose as high as 1024 μg/mL on the basis of the tested adhesion, spreading of the cells, and also on the various serological, biochemical, and histological investigations of the vital organs and blood of the Charles Foster Rat. These results suggest that MQCs have potent antimicrobial activities against hvKP and other drug resistant isolates and therefore may be used as broad spectrum antibacterial and antibiofilm agents.

Selenium-Modified TiO2 Nanoarrays with Antibacterial and Anticancer Properties for Postoperation Therapy Applications.

After surgical resection of osteosarcoma, there is an obligatory need to implement postoperative therapies for preventing possible infection and/or recurrence. The therapeutic agents and employed methods thus need to fulfill antibacterial and anticancer requirements. A type of selenium (Se)-modified titanium dioxide (TiO2) nanoarray was developed and used as potential implants for the postoperative treatment of osteosarcoma. The TiO2 nanoarray was fabricated via a seed-mediated hydrothermal method, and the Se-modification was conducted by electrochemical deposition method. The Se-modified TiO2 nanoarrays containing varied amounts of Se were tested for the safe Se dose as well as for antibacterial and anticancer properties, basing on the interactions between the nanoarrays and different kinds ofcells or bacteria. It was found that the maximal safe dose of Se should be controlled about 6.43 wt % or less on the basis of the tested adhesion and spreading of MC3T3-E1 cells. The Se-modified TiO2 nanoarray containing about 6.43 wt % of Se showed promising antibacterial abilities against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Meanwhile, it was also capable of suppressing the growth of MG63 cells, a kind of osteosarcoma cells. These results suggest that such Se-modified TiO2 nanoarrays have potential in the use of implants for the postoperative therapy of osteosarcoma.

Superior photoelectrochemical properties of BiVO4 nanofilms enhanced by PbS quantum dots decoration

Abstract Novel BiVO4 nanofilms decorated with PbS quantum dots (PbS QDs/BiVO4) have been successfully fabricated via a seed-mediated hydrothermal method and subsequent spin-coating process. The photoelectrochemical (PEC) tests demonstrate that the as-fabricated PbS QDs/BiVO4 nanofilms exhibit enhanced PEC activity compared with the obtained pure BiVO4 nanofilms. The photocurrent density is 0.68 mA cm−2 for the PbS QDs/BiVO4 photoelectrode at 0.5 V vs. Ag/AgCl electrode, which is much higher than that (0.36 mA cm−2) of the pure BiVO4 photoelectrode. The incident photon-to-current conversion efficiency (IPCE) of ∼5.9% at 370–450 nm for the PbS QDs/BiVO4 photoelectrode is almost two times higher than that (∼3%) of the pure BiVO4 photoelectrode. The deposition of PbS QDs on the surface of BiVO4 nanofilms extends their visible-light harvesting capability and accelerates charge separation of the photoelectrode, which are considered to be the main contributions to enhanced PEC activity of the as-prepared PbS QDs/BiVO4 photoelectrode. The present work demonstrates that the PbS QDs/BiVO4 nanofilms have potential applications in efficient PEC energy conversion system.

WO3Nanowires on Graphene Sheets as Negative Electrode for Supercapacitors

WO3nanowires directly grown on graphene sheets have been fabricated by using a seed-mediated hydrothermal method. The morphologies and electrochemical performance of WO3films prepared by different process were studied. The results show that the precoated nanoseeds and graphene sheets on graphite electrode provide more reactive centers for the nucleation and formation of uniform WO3nanowires. The WO3nanowires electrode exhibits a high area specific capacitance of 800 mF cm−2over negative potential range from −1.0 V to 0 V versus SCE in 1 M Li2SO4solution. A high performance electrochemical supercapacitor assembled with WO3nanowires as negative electrode and PANI/MnO2as positive electrodes over voltage range of 1.6 V displays a high volumetric capacitance of 2.5 F cm−3, which indicate great potential applications of WO3nanowires on graphene sheets as negative electrode for energy storage devices.

Effect of Concentration Ratio of Precursor-Surfactant Solution on The Performance of Boron-doped ZnO Nanotubes Dye Sensitized Solar Cells

Boron doped zinc oxide (ZnO) nanotubes have successfully been grown using seed-mediated hydrothermal method at various concentrations of precursor-surfactant solution. The growth of ZnO nanotubes was carried out at a temperature of 90°C for 8 hours and a drop in temperature to 50°C for 16 hours. In this study, the effect of concentration ratio of precursor-surfactant was evaluated. Samples were characterized using UV-Vis Spectroscopy, X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray (EDX). UV-Vis spectra of the samples showed that the ZnO nanotubes were grown on the Flourine Tin Oxide (FTO) and the strong absorption occurred in the wavelength range of 300-400 nm, which is typical spectrum for hexagonal-nanostructure. XRD patterns showed five diffraction peaks at 2θ = 32.05°, 34.5°, 36.35°, 47.75° and 56,9°. The analysis of EVA Diffrac Plus confirmed the peaks were represented to the lattice of (100), (002), (101), (102), and (110) respectively. FESEM images of the samples showed the hexagonal-shaped ZnO nanotubes with an average diameter of 50-340 nm and an average thickness of 1.2 - 4.4 μm observed for all samples. Uniformity the size and shape of ZnO nanotubes become higher as concentrations of ZNH decreased. The EDX spectra of the samples showed the percentage of weight of Zn, O, and B was 69.35%, 21.60% and 4.76% respectively, while the percentage of their atoms was 33, 06%, 42.08% and 13.71% respectively. The B-doped ZnO nanotubes solar cells were fabricated by arranging a sandwich structure, consisting of the FTO, ZnO nanotubes, dye, electrolyte and platinum thin film. I-V characteristics of cell were carried out under irradiation of 100 mWcm<sup>-2</sup> halogen lamp. The I-V curves produced the highest efficiency from the cells utilizing the B-doped ZnO nanotubes with their concentration ratio of precursor-surfactant of 0.1 M : 0.04 M as the active material, which was 0.352%. This value is much higher than that of pure ZnO nanotube based DSSC of 0.05%.

Effect of Concentration Ratio of Precursor-Surfactant Solution on The Performance of Boron-doped ZnO Nanotubes Dye Sensitized Solar Cells

Boron doped zinc oxide (ZnO) nanotubes have successfully been grown using seed-mediated hydrothermal method at various concentrations of precursor-surfactant solution. The growth of ZnO nanotubes was carried out at a temperature of 90°C for 8 hours and a drop in temperature to 50°C for 16 hours. In this study, the effect of concentration ratio of precursor-surfactant was evaluated. Samples were characterized using UV-Vis Spectroscopy, X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray (EDX). UV-Vis spectra of the samples showed that the ZnO nanotubes were grown on the Flourine Tin Oxide (FTO) and the strong absorption occurred in the wavelength range of 300-400 nm, which is typical spectrum for hexagonal-nanostructure. XRD patterns showed five diffraction peaks at 2θ = 32.05°, 34.5°, 36.35°, 47.75° and 56,9°. The analysis of EVA Diffrac Plus confirmed the peaks were represented to the lattice of (100), (002), (101), (102), and (110) respectively. FESEM images of the samples showed the hexagonal-shaped ZnO nanotubes with an average diameter of 50-340 nm and an average thickness of 1.2 - 4.4 μm observed for all samples. Uniformity the size and shape of ZnO nanotubes become higher as concentrations of ZNH decreased. The EDX spectra of the samples showed the percentage of weight of Zn, O, and B was 69.35%, 21.60% and 4.76% respectively, while the percentage of their atoms was 33, 06%, 42.08% and 13.71% respectively. The B-doped ZnO nanotubes solar cells were fabricated by arranging a sandwich structure, consisting of the FTO, ZnO nanotubes, dye, electrolyte and platinum thin film. I-V characteristics of cell were carried out under irradiation of 100 mWcm<sup>-2</sup> halogen lamp. The I-V curves produced the highest efficiency from the cells utilizing the B-doped ZnO nanotubes with their concentration ratio of precursor-surfactant of 0.1 M : 0.04 M as the active material, which was 0.352%. This value is much higher than that of pure ZnO nanotube based DSSC of 0.05%.

Enhanced mechanical and thermal properties of hybrid SnO2–woven carbon fiber composites using the facile controlled growth method

Tin oxide (SnO2) nanorods (NRs) were successfully grown using a two-step seed-mediated hydrothermal method in the absence of surfactants. The enhanced mechanical properties of the impact absorbed energy (71.65%), ultimate tensile strength (35.07%), in-plane shear strength (49.07%) and elastic modulus (44.15%) were obtained for 70 mM of SnO2–woven carbon fiber (WCF) composites. The higher electrical resistive heating in the interlaminar region of electrified SnO2 (70 mM)–WCF composite sheets was observed at 108.92% improvement of an average temperature under an applied current of 3 A for 20 min. It was attributed to the fact that a higher SnO2 NR content provided secondary reinforcement and subsidiary electrified heat traps by modifying the interphase region between the CFs and polymers. X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to examine the morphology and phase structure of one-dimensional (1D) grown SnO2 NR arrays. The crystalline 1D SnO2 nanostructure evolved via a self-assembly mechanism that depended on nuclei of Sn4+/OH− ions in a supersaturated solution at a pH of about 13. This facile controlled growth of SnO2 embedded in CF composites is relevant to engineering applications requiring higher mechanical performance and thermal heating than attainable with conventional CF-reinforced polymer composites.

Electrical thermal heating and piezoresistive characteristics of hybrid CuO–woven carbon fiber/vinyl ester composite laminates

The electric heating and piezoresistive characteristics of CuO–woven carbon fiber (CuO–WCF) composite laminates were experimentally evaluated. Hybrid CuO–WCF composites were fabricated via a two-step seed-mediated hydrothermal method. The interlaminar interface between two plies of hybrid CuO–WCF/vinyl ester composite laminae was influenced by interlocked fiber–fiber cross-linking structures with CuO NRs and acted as electric heating and resistance elements. The contribution of CuO NRs (10–110mM) to the interlaminar interface was determined by measuring the temperature profile, in order to investigate the electrical resistive heating behavior. At higher concentration of CuO NRs growth in the interlaminar region applied by 3A, the average temperature reached to 83.55°C at the interface area 50×50mm2 and the heating efficiency was 0.133W/°C owing to radiation and convection given by 10.5W (3A, 3.5V). To investigate the piezoresistive response, the through-thickness gauge factor was observed at 0.312 during Joule heating applied by 2A, compared with 0.639 at an ambient air temperature for CuO 110mM concentration. The morphology and crystallinity of CuO NRs were investigated using scanning electron microscopy and X-ray diffraction analyses, respectively. The temperature dependence of hybrid CuO–WCF composite laminates’ storage moduli were analyzed using a dynamic mechanical analyzer. These characterizations showed that the interlaminar interface, combined with the high specific surface area of CuO NRs, provided the electron traps for electrical conduction around multiple WCF junctions and adjacent cross-linked laminae.

Effect of CuO nanostructure morphology on the mechanical properties of CuO/woven carbon fiber/vinyl ester composites

The effect of CuO nanostructure morphology on the mechanical properties of CuO/woven carbon fiber (WCF)/vinyl ester composites was investigated. The growth of CuO nanostructures embedded in the surface of woven carbon fibers (WCFs) was carried out by a two-step seed-mediated hydrothermal method; i.e., seeding and growth treatments with controlled chemical precursors. CuO nanostructural morphologies ranging from petal-like to cuboid-like nanorods (NRs) were obtained by controlling the thermal growth temperature in the hydrothermal process over a growth time of 12h. The Cu2+/O− ratio and the rate of reaction greatly influenced the formation of CuO nanostructures as self-assembled shapes on the crystal planes in the order L[010]>L[100]>L[001]. Morphological variations were analyzed by scanning electron microscopy, X-ray diffraction, and Brunauer–Emmett–Teller surface area analysis. The impact behavior, in-plane shear strength, and tensile properties of the CuO/WCF/vinyl ester composites were analyzed for different CuO NR morphologies at various growth temperatures and molar concentrations. The CuO/WCF/vinyl ester composites had improved impact energy absorption and mechanical properties because the higher specific surface area of CuO NRs grown as secondary reinforced nanomaterials on WCFs enhanced load transfer and load-bearing capacity.

Non-centrosymmetric Au–SnO2 hybrid nanostructures with strong localization of plasmonic for enhanced photocatalysis application

We present an innovative approach to the production of sub-100 nm hollow Au-SnO2 hybrid nanospheres, employing a low-cost, surfactant-free and environmentally friendly solution-based route. The hollow hybrid nanostructures were synthesized using a seed-mediated hydrothermal method, which can be divided into two stages: (1) formation of multicore-shell Au@SnO2 nanoparticles (NPs) and (2) thermal diffusion and ripening to form hollow Au-SnO2 hybrid NPs. The morphology, optical properties and formation mechanism were determined by a collection of joint techniques. Photocatalytic degradation of Rhodamine B (RhB) in the liquid phase served as a probe reaction to evaluate the activity of the as-prepared hollow hybrid Au-SnO2 NPs under the irradiation of both visible light and ultraviolet light. Significantly, the as-obtained Au-SnO2 hybrid nanostructures exhibited enhanced visible light or UV photocatalytic abilities, remarkably superior to commercial pure SnO2 products and P25 TiO2, mainly owing to the effective electron hole separation at the SnO2-Au interfaces and strong localization of plasmonic near-fields effects.

High energy density asymmetric supercapacitors with a nickel oxide nanoflake cathode and a 3D reduced graphene oxide anode

Here we demonstrate a high energy density asymmetric supercapacitor with nickel oxide nanoflake arrays as the cathode and reduced graphene oxide as the anode. Nickel oxide nanoflake arrays were synthesized on a flexible carbon cloth substrate using a seed-mediated hydrothermal method. The reduced graphene oxide sheets were deposited on three-dimensional (3D) nickel foam by hydrothermal treatment of nickel foam in graphene oxide solution. The nanostructured electrodes provide a large effective surface area. The asymmetric supercapacitor device operates with a voltage of 1.7 V and achieved a remarkable areal capacitance of 248 mF cm(-2) (specific capacitance of 50 F g(-1)) at a charge/discharge current density of 1 mA cm(-2) and a maximum energy density of 39.9 W h kg(-1) (based on the total mass of active materials of 5.0 mg). Furthermore, the device showed an excellent charge/discharge cycling performance in 1.0 M KOH electrolyte at a current density of 5 mA cm(-2), with a capacitance retention of 95% after 3000 cycles.

Synthesis of aligned copper oxide nanorod arrays by a seed mediated hydrothermal method

The synthesis of ordered copper oxide (CuO) nanorod arrays has been obtained using a seed-mediated hydrothermal method. Aligned CuO nanorods were obtained on fluorine doped tin oxide glass substrates over a large scale at low temperature ranging from 75 to 85 °C. It is found the CuO nanoseeds play an important role to facilitate the growth of those aligned CuO nanorods. The band gap energy of the CuO nanorods was estimated by ultraviolet–visible absorption spectroscopy. The growth mechanism of this method was also investigated.