Introduction Of ZnO Research Articles

Enhancing 2.7 µm emission of Er3+ in bismuth glass by introducing ZnO

In recent years, 2.7 μm lasers have attracted the attention of many researchers due to their wide application in military, medical, aerospace and other fields. This study investigates the gain effect of ZnO on Er3+-doped bismuthate glasses by partially replacing GeO2 in the glass with ZnO. It is found that under 980 nm pump excitation, with the increase of ZnO, the emission of Er3+ at 1.5 μm and 2.7 μm was enhanced. This result is consistent with the changing trend of J-O parameter Ω2. All these results confirmed that the introduction of ZnO into bismuthate glasses is a reasonable and effective method to enhance the mid-infrared 2.7 μm emission in Er3+-doped bismuthate glasses. Therefore, the current research indicates that an appropriate amount of ZnO in Er3+-doped bismuthate glasses is a suitable materials for 2.7 um fiber lasers.

ZnO enhanced molten Na2CO3-K2CO3 system for simulated waste resins treatment: Efficient conversion and fixation of organic sulfur and iron(III)

The radioactive spent resins from pressurized water nuclear power plant always contain a significant proportion of 55Fe, which invariably leads to the release of radionuclides and acidic gases if not treated promptly. Herein, an efficient ZnO enhanced molten salt oxidation (MSO) method was established for the removal and fixation of organic sulfur and Fe in simulated radioactive resins containing Fe3+ (Fe-CERs). The existence of Fe3+ facilitates the reaction with O2 to form Fe2O3, which contributes to the fracture of organic skeleton. The comparative study was conducted to explore the impact of ZnO on the oxidation behavior of Fe and S at 600–800 °C. The introduction of ZnO caused the continuous formation of ZnS at 600–700 °C, and the conversion of ZnO at 800 °C indirectly promotes the retention rate of S (85.42 %). The potential conversion of Zn0.73Fe0.27S to ZnS may occur within the temperature range of 700 °C to 800 °C. Additionally, the predominant presence of carbon in residues at approximately 700 °C could exert a stimulating effect on the sulfidation process of Fe2O3 and inhibit the formation of SO2. The coexistence of Fe2O3, carbon and ZnO effectively diminishes H2S and SO2 amounts while further enhancing the fixation of S and Fe. The increase generation of K2SO4, FeS and Fe3O4 leads to a high formation rate of SO42- (79.36 %) and a great retention efficiency of Fe (96.23 %) at 800 °C. The proposed novel MSO method holds promising potential for applications in the treatment of organic contaminants.

Continuous Sandwiched Film Containing Oriented ZnO@HDPE Microfiber for Passive Radiative Cooling

AbstractRecently, passive radiative cooling (PRC) that realizes thermal management without consuming any energy has attracted increasing attention. However, few studies focus on low‐cost and robust PRC film fabricated by a facile and environmentally friendly method. In this study, via coextrusion blow film molding and water leaching, sandwiched PRC film (SPRCF) is efficiently prepared, and its skin and core layer are respectively high‐density polyethylene (HDPE) film and oriented ZnO@HDPE microfiber layer. Of note, such a sandwiched structure enables SPRCF to possess remarkable mechanical properties, abrasion, and weather resistance. Moreover, with the introduction of ZnO, SPRCF shows lower sunlight transmittance (≈3.8%) but higher mid‐infrared transmittance (≈88.8%), endowing it with remarkable PRC performance (the maximum cooling power of daytime and nighttime are respectively 73.8 and 96.7 W m−2). Furthermore, the decent self‐cleaning performance of SPRCF‐45 endows it with maintenance‐free features outdoors. This work proposes a facile and environmentally friendly method for preparing low‐cost and robust SPRCF, opening a new pathway to develop PRC film following the concept of polymer “structuring” processing.

ZnO-PLLA/PLLA Preparation and Application in Air Filtration by Electrospinning Technology.

With the increasing environmental pollution caused by disposable masks, it is crucial to develop new degradable filtration materials for medical masks. ZnO-PLLA/PLLA (L-lactide) copolymers prepared from nano ZnO and L-lactide were used to prepare fiber films for air filtration by electrospinning technology. Structural characterization of ZnO-PLLA by H-NMR, XPS, and XRD demonstrated that ZnO was successfully grafted onto PLLA. An L9(43) standard orthogonal array was employed to evaluate the effects of the ZnO-PLLA concentration, ZnO-PLLA/PLLA content, DCM(dichloromethane) to DMF(N,N-dimethylformamide) ratio, and spinning time on the air filtration capacity of ZnO-PLLA/PLLA nanofiber films. It is noteworthy that the introduction of ZnO is important for the enhancement of the quality factor (QF). The optimal group obtained was sample No. 7, where the QF was 0.1403 Pa-1, the particle filtration efficiency (PFE) was 98.3%, the bacteria filtration efficiency (BFE) was 98.42%, and the airflow resistance (Δp) was 29.2 Pa. Therefore, the as-prepared ZnO-PLLA/PLLA film has potential for the development of degradable masks.

Introduction of ZnO, Sn, and P promoters in CuO/CeO2 catalysts for improved production of dimethyldichlorosilane in the Rochow-Müller reaction

Developing an efficiently supported Cu-based catalyst with promoters to substitute the existing non-supported Cu-based catalysts is highly desirable to the Rochow-Müller reaction. Using a simple ball-milling method and CeO2 support, we prepared a high-performance CuO-ZnO-P-Sn/CeO2 catalyst by integrating highly dispersed multicomponent promoters of ZnO, Sn, and P with the active component CuO. This catalyst shows a significantly enhanced dimethyldichlorosilane selectivity because these promoters can substantially increase the Cu+ content and the formation of an active CuxSi phase. This work provides a new approach to efficiently designing Cu-based catalysts for the Rochow-Müller reaction.

A Research on Delayed Thermal Depolarization, Electric Properties, and Stress in (Bi0.5Na0.5)TiO3-Based Ceramic Composites.

Depolarization behavior is one of the main shortcomings of (Bi0.5Na0.5)TiO3-based ceramics. Considering the undesirable efficiency of traditional modification methods, in this paper a series of 0–3 type ceramic composites 0.85(Bi0.5Na0.5)TiO3-0.11(Bi0.5K0.5)TiO3-0.04BaTiO3-x mol% ZnO (BNKT-BT-xZnO)) were synthesized by introducing ZnO nanoparticles. The results of the X-ray diffraction pattern (XRD) and energy dispersive spectroscopy (EDS) demonstrate that the majority of ZnO nanoparticles grow together to form enrichment regions, and the other Zn2+ ions diffuse into the matrix after sintering. With ZnO incorporated, the ferroelectric–ergodic relaxor transition temperature, TF-R, and depolarization temperature, Td, increase to above 120 °C and 110 °C, respectively. The research on temperature-dependent P–E loops verifies an attenuated ergodic degree induced by ZnO incorporation. For this reason, piezoelectric properties can be well-maintained below 110 °C. The electron backscatter diffraction (EBSD) was employed to investigate the stress effect. Orientation maps reveal the random orientation of all grains, excluding the impact of texture on depolarization. The local misorientation image shows that more pronounced strain appears near the boundaries, implying stress is more concentrated there. This phenomenon supports the hypothesis that potential stress suppresses depolarization. These results demonstrate that the depolarization behavior is significantly improved by the introduction of ZnO. The composites BNKT-BT-xZnO are promising candidates of lead-free ceramics for practical application in the future.

Glass formation and properties of the TeO2-ZnO-BaO tellurite optical glasses

We report the thorough study on glass forming ability and properties of the TeO2-ZnO-BaO (TZB) optical glasses prepared by the melt-quenching method at 900 °C. The attention has been paid to investigation of thermal, structural, and optical properties of glasses with content of TeO2 from 52.5 up to 90%. The introduction of ZnO and/or BaO into TeO2-based glass results in increase of the glass transition temperature Tg from 319 to 369 °C and decrease of the refractive index and density of prepared glasses. The structure of studied TZB glasses was investigated by Raman scattering. Since the TZB glasses exhibit good thermal stability, wide spectral region of transparency from ultraviolet (UV), λ ≈ 0.35 μm, up to mid-infrared (MIR), λ ≈ 6 μm, wavelengths with high values of refractive index (n1550 ≈ 1.87–2.04), they may be utilized as optical materials, which can be designed on the results presented in this paper.

The Role of ZnO as a Dopant and an Intergranular Phase in the Electrical Properties of Ca0.6Sr0.4TiO3 Ceramics

ZnO was introduced into Ca0.6Sr0.4TiO3ceramics as a dopant and an intergrangular phase in this research, followed by detailed structure characterization, energy storage performance analysis, and electrical behavior studies. The results revealed that the existence of ZnO as a dopant led to the decrease of conduction activation energy and the deterioration of energy storage behavior, while appropriate introduction of ZnO as an intergranular phase resulted in the increase of conduction activation energy and the optimization of energy storage performance. Additionally, the inverse relation between interfacial polarization and energy storage performance was observed in this study. Finally, an increased energy storage density of 1.16 J/cm3was achieved in 1 mol% ZnO-added Ca0.6Sr0.4TiO3ceramics.

Uniformly Dispersed Nano-ZnO Particles Reinforced Copper Matrix by Chemical Coprecipitation Method

Nano-copper-based materials are wildly applied in the microelectronics and aerospace industries, which not only maintain the advantages of copper materials, but also make up for the shortage of copper. ZnO in ZnO-Copper composite prepared by chemical coprecipitation was evenly distributed in the copper matrix in the form of hexagonal nanosheets. The maximum hardness of the composite can reach a maximum of 119.44Hv, and the minimum wear rate is only 0.6% of pure copper; meanwhile, the density and the conductivity both decrease slightly. The relative density of composite with ZnO content of 4% and 8.% exceeds 96%. The rates exceeds 70% IACS. However, The results suggest that the introduction of ZnO reduces the corrosion resistance of the copper matrix, and the corrosion weight loss of 20 wt.% ZnO is nearly 3 times that of pure copper.

In Situ Construction of ZnO/Ni2S3 Composite on Ni Foam by Combing Potentiostatic Deposition with Cyclic Voltammetric Electrodeposition.

The ZnO/Ni2S3 composite has been designed and in situ synthesized on Ni foam substrate by two steps of electrodeposition. ZnO was achieved on Ni foam by a traditional potentiostatic deposition, followed by cyclic voltammetric (CV) electrodeposition, to generate Ni2S3, where the introduction of ZnO provides abundant active sites for the subsequent Ni2S3 electrodeposition. The amount of deposit during CV electrodeposition can be adjusted by setting the number of sweep segment and scan rate, and the electrochemical characteristics of the products can be readily optimized. The synergistic effect between the ZnO as backbones and the deposited Ni2S3 as the shell enhances the electrochemical properties of the sample significantly, including a highly specific capacitance of 2.19 F cm−2 at 2 mA cm−2, good coulombic efficiency of 98%, and long-term cyclic stability at 82.35% (4000 cycles).

Studies on adhesion strength and corrosion behavior of ZnO-Mg coated on AISI 4140

The electrolytic ZnO based alloy coating with admixed interfacial blend of Mg have been successfully coated on medium carbon steel (AISI 4140) substrate by spray coating technique over a range of applied current density and dwell time. The structural and morphological properties of the coated samples are characterized using Optical Microscope (OM), Scanning Electron Microscope (SEM), X-ray Diffraction Analysis (XRD) and Energy Dispersive Spectroscopy (EDS) analysis. The adhesion test was carried out using scratch testing. The corrosion behavior is evaluated in a chloride environment (NaCl) by Tafel exploration as a function of coating thickness. The results revealed that the introduction of ZnO-Mg particles increases the adhesion strength of the AISI 4140. During scratching, cracks parallel with the scratch channel, external transverse cracks, adhesive spalling, and complete breaking of the coating within the scratch channel were observed. The acquired results exhibit that the introduction of ZnO - Mg coating improves corrosion resistance of AISI 4140 in NaCl solution. Equally, deposition thickness significantly affected the adhesion and corrosion properties. Increasing the coating thickness from 30 µm to 90 µm leads to decreasing the adhesion and corrosion properties.

Effect of acceptor concentration in the FRET controlled photoluminescence of PMMA-ZnO nanocomposite for the application of PLED device

Luminescent PMMA-ZnO nanocomposites are synthesised through bulk polymerization of MMA in presence of ex-situ prepared ZnO nanoplates. Variation of ZnO concentration affects the optical properties of the composite. Introduction of ZnO in the PMMA matrix makes the composite as semiconducting in nature by creating a lower energy gap in the composite. Again Förster resonance energy transfer (FRET) between PMMA (donor) to ZnO (acceptor) enhances emission of ZnO significantly. But the enhanced emission decreases with increase in ZnO concentration, i.e. the emission intensity of PMMA-ZnO nanocomposite shows an increasing trend with decrease in the content of ZnO. The energy transfer efficiency varies from 97% to 52% when the concentration of ZnO varies from 10 wt% to 30 wt%. The Photoluminescence quantum efficiency of the composite showing highest emission is calculated and found to be 74%. Corresponding theoretically calculated electroluminescence quantum efficiency is 4% at an operating voltage of 3.1 V assuming all the injected charge carriers can generate singlet exciton if the composite showing highest emission is used as an emissive layer in PLED.

Local structure and conductivity of highly conductive vanadate glasses containing different metal oxides

Heat treatment of 20BaO·xMmOn·(10−x)Fe2O3·70V2O5 glasses containing different metal oxides (MmOn), such as Fe2O3, Al2O3, MnO2, CuO, Cu2O, ZnO, Ga2O3, GeO2, MoO3, SnO2 and WO3, was accompanied by a remarkable decrease in DC-resistivity (ρ) at room temperature from the order of MΩ cm to Ω cm. N-type semiconductor model could be successfully applied to discuss the conduction mechanism. Introduction of CuO into network former (NWF) sites caused a remarkable change of ρ from 2.6 × 105 to 3.1 Ω cm when annealed at 450 °C for 30 min. Activation energy for conduction (Ea) decreased from 0.16 to 0.10 eV, suggesting an increased carrier density in the conduction band. Diffuse reflectance spectra of this glass showed a decrease in the bandgap energy (Eg) from 2.41 to 2.14 eV. Introduction of ZnO into network modifier (NWM) sites resulted in a remarkable decrease in ρ from 4.0 × 105 to 4.8 Ω cm after annealing at 450 °C for 30 min, together with a decrease in Ea from 0.23 to 0.14 eV. Diffuse reflectance spectra showed a decrease in Eg from 2.39 to 2.11 eV. These results prove that heat treatment of vanadate glass causes structural relaxation and concordant decrease in Ea and Eg which are responsible for the remarkable increase in the high conductivity.

Printed resistors for flexible electronics—thermal variance mitigation and tolerance improvement via oxide-metal coatings

Manufactured resistors in conventional electronics are classified into tolerance groups ranging from <1% for high stability film types (E192) to 20% (E6) which are often carbon-based and utilised in less critical resistance value contexts such as current limiting or pull-up/down applications [IEC 60063:2015, Preferred number series for resistors and capacitors. One of the major identified challenges in the printed electronics industry currently is the ability to match this manufacturing capability for printed resistors in terms of initial tolerance, stability over time and power capabilities. In this work, a variety of screen-printed carbon resistors were designed and produced. The effects of utilising additional screen-printed ZnO and Ag layers as thermal variance management for the carbon resistors are investigated with the aim of improving the resistors power rating and stability. The introduction of ZnO or ZnO/Ag layers to carbon resistors saw notable improvements in the peak power capability, stability when sustaining 500 mW power dissipation, and stability in varying environmental conditions. Utilizing ZnO and Ag layers also notably improved the initial tolerance groupings when compared to basic uncoated carbon resistors.

Performance analysis of MgO/ZnO multilayer thin film as heat spreader on Al substrates for high-power LED thermal management applications

Towards improving structural, surface, and thermal properties of MgO heat spreader, ZnO thin film was interstacked into MgO. This would improve heat dissipation and keeping the temperature as well as the junction temperature of LEDs in safe operating conditions and make the MgO/ZnO multilayer thin film as a reliable heat spreader material in thermal management application. XRD measurements, FESEM, and AFM analysis were employed in examining the structure, morphology, particle size, and topography of the spin-coated monolithic MgO and multilayer MgO/ZnO thin films, respectively. Improvement in crystal size, reduction in residual stress, lattice strain, and dislocation density were recorded for MgO/ZnO multilayer films. Similarly, introduction of ZnO into MgO resulted an improvement in surface morphology with large particle size (76 nm) and decrease in surface roughness from 19.1 to 9.6 nm. From thermal transient analysis, a noticeable difference in junction temperature raise (ΔTJ = 27.07 °C) and high difference in total thermal resistance (ΔRth-tot = 5.3 K/W) were recorded for LED fixed on 6:4 L MgO:ZnO thin film-coated aluminum substrate. Introduction of ZnO into MgO improves the structure and surface qualities as well as thermal performance of MgO thin film and LEDs mounted on them. The optimized multilayer MgO/ZnO ceramic-ceramic composite thin film could be employed for efficient, reliable, and longer life LEDs thermal management as heat spreader.

Improved Charge Transfer Contribution by Cosputtering Ag and ZnO.

A two-dimensional polystyrene microsphere array cosputtered with Ag and ZnO was designed for evaluating surface-enhanced Raman scattering (SERS) activity. The surface plasmon resonance (SPR) and SERS properties were significantly changed by the introduction of ZnO into the Ag film. By increasing the Ag sputtering power, a redshift of the SPR peak was obtained. Moreover, improved SERS activity occurred because of the electromagnetic (EM) contribution from the increasing Ag content and the charge transfer (CT) contribution from the introduction of ZnO. More importantly, the Hall effect was employed to evaluate the carrier density effect on the SERS contribution of the Ag/ZnO film. The increase in the carrier density as the Ag sputtering power increased indicated an increasing number of free electrons stored in the Ag/ZnO film, which was accompanied by improved EM and CT contributions.

Performance and reaction mechanism of MgO/ZnO/Graphene ternary nanocomposite in coupling with LED and ultrasound waves for the degradation of sulfamethoxazole and pharmaceutical wastewater

In this paper, we investigated sonophotocatalytic degradation of sulfamethoxazole (SUX) antibiotic in pharmaceutical wastewaters by employing a ternary heterostructure catalyst composed of MgOand ZnO nanoparticles anchored on graphene nanosheets (MZG) under UV-A (LED) and US irradiations as a novel study. Synthesis of MZG was performed via multi-step hydrothermal-assisted method and characterizedby employing XRD, FT-IR, FESEM, BET, EIS, DRS, EDS, TEM, EDX, and TGA techniques. By introduction of ZnO and graphene, photocatalytic activity of MgO was enhanced in both UV and visible regions. A good catalytic potential and significant synergistic effect was obtained for ternary system (MZG/LED/US) compared to binary and single processes. After 120 min of sonophotocatalytic treatment, complete degradation of SUX (55 mg/L) can be attained at MZG: 0.8 g/L, pH: 9.0, LED power: 90 W and US power: 250 W. Kinetic studies revealed that sonophotocatalytic degradation process followed the pseudo first-order kinetic model. HO species were detected as dominant oxidative free radicals which contributed in SUX degradation process. A comprehensive possible mechanism was proposed for photocatalysis and sonocatalysis processes involved in MZG/LED/US system in detail. The nanocomposite was reused for six successive cycles with maximum 9.8% drop in degradation efficiency. An efficient improvement was achieved in the biodegradability of real pharmaceutical wastewater after treatment by MZG/LED/US with 94% and 81% removal of COD and TOC, respectively. To conclude, combining MZG, LED and US waves can be utilized as a novel and efficient strategy to treat real pharmaceutical wastewaters in practical applications, owing to high performance in degradation/mineralization, excellent reusability potential and high activity in sonolysis and photolysis systems.

Multi-phase coexistence and temperature-stable dielectric properties in BaTiO3/ZnO composite ceramics

BaTiO3:100xZnO composite ceramics with different ZnO particle sizes were prepared by using a conventional solid-state method. Phase constitution, microstructure and dielectric properties of BaTiO3:100xZnO composite ceramics are investigated. Compared to micrometer scaled ZnO particles, nanometer scaled ZnO particles tend to agglomerate at lower ZnO contents in the BaTiO3:100xZnO composite ceramics. The introduction of ZnO in BaTiO3 leads to the reduction of grain size, decrease of the tetragonality and shift of phase transition temperature. The optimum composition is BaTiO3 with 20 wt. % nanometer scaled ZnO particles, which has stable permittivity and low dielectric loss from -100 to 160 °C. The stable dielectric properties are proposed to be beneficiated from the stress induced multi-phase coexistence.

Preparation and characterization of polypropylene composites reinforced by functional ZnO/lignin hybrid materials

Abstract The aim of this study was to obtain polypropylene composites filled with a ZnO/lignin hybrid filler and to examine their chemical and mechanical properties. Inorganic-organic hybrid materials were obtained using an environmentally-friendly, low-cost mechanical method. The use of an inorganic component mainly influenced the improvement of thermal properties, in turn, the use of lignin was mainly supported by its low price as well as unique properties. The effectiveness of ZnO/lignin materials production was confirmed using Fourier transform infrared spectroscopy and, indirectly, by colorimetric analysis. In addition, the thermal stability and porous structure analyses were also carried out. Polymer composites containing 3 wt% of each filler were subjected to wide angle X-ray diffraction tests and differential scanning calorimetry studies to define their supermolecular structure as well as thermal properties. Polarized light microscopy was performed to assess the influence of fillers on the crystallization of polypropylene. Tensile tests provided information regarding the mechanical properties of produced materials. The presence of hybrid fillers influences the nucleation activity and it was responsible for an increased crystallinity degree of composite samples. It was also established that introduction of ZnO and hybrid fillers with high amount of ZnO into the polypropylene matrix resulted in a significant increase of density of the formed nuclei.

Zinc oxide modified HZSM-5 as an efficient acidic catalyst for hydrogen production by steam reforming of dimethyl ether

The parent HZSM-5 was modified with a series content of ZnO via the incipient impregnation method by using Zn(NO3)2·6H2O as a precursor. And the ZnO-modified HZSM-5 physically mixed with a commercial Cu/ZnO/Al2O3 was investigated as a bifunctional catalyst for steam reforming of dimethyl ether (DME). The samples were systematically characterized by XRD, FT-IR, N2 adsorption–desorption at low temperature, and NH3-TPD techniques. It was found that the introduction of ZnO would slightly influence the structure and crystallinity of the parent HZSM-5. Furthermore, the type (Lewis and Bronsted acid) and distribution (strong and weak acid sites) of acid could be adjusted by altering the content of ZnO, which took responsible for the DME conversion, H2 yield, and selectivity of the carbon-containing products. As a result, an efficient catalyst for steam reforming of DME was obtained by adjusting the content of ZnO.