Decorated ZnO Nanorods Research Articles

3D SERS substrate using silver nanoparticles decorated ZnO nanorods on silicon micropyramids hybrid heterostructure

3D hybrid heterostructure have been fabricated using Ag Nanoparticles decorated ZnO nanorods over textured Silicon Micropyramid for Surface Enhanced Raman Scattering (SERS) applications. Silicon texturing was performed using facile Alkaline texturing route followed by the growth of ZnO nanorods (ZnONR) array on the micropyramids over which, the Ag nanoparticles (AgNPs) were decorated. The phase and the surface of the heterostructure was studied by XRD and Field Emission Scanning Electron Microscope (FESEM), respectively. The SERS performance of the 3D heterostructure was evaluated using Rhodamine 6G (R6G) at various concentrations with a detection limit of 0.1 pM. The superior properties of SiMP/ZnONR/AgNP over ZnONR/AgND heterostructure has also been presented to understand the effect of the 3D pyramidal substrate for superior SERS performance. The recovery of the prepared heterostructure has also been demonstrated by photocatalytic degradation of Rhodamine 6G and Methylene Blue. Our work demonstrates a facile synthesis of 3D SERS heterostructure and sheds light on its superior SERS properties paving ways for wide range of applications in bio-sensors, detection of harmful chemicals, food adulterations, narcotic detection and many more.

Polyurethane foam reinforced with Ag nanoparticle decorated ZnO nanorods: a dual-functional approach for improved antibacterial and mechanical properties

Abstract This study introduces a novel approach by incorporating pristine ZnO nanorods and Ag nanoparticles decorated ZnO nanorods into a polyurethane foam matrix. This synergistic combination aims to enhance the foam’s antibacterial properties while investigating its impact on mechanical strength. Nanoparticles and prepared nanopolymer were characterized by different methods like XRD, TEM, SEM, and EDS. The mechanical characteristics and antibacterial properties of prepared polyurethane composites were investigated in the presence of Escherichia coli and Bacillus subtilis. A much higher level than reported in the literature was found for PU films filled with ZnO nanorods. Incorporating nanoparticles into polyurethane nanocomposites has been demonstrated to significantly improve polyurethane’s antibacterial properties. The results revealed that ZnO/PU antibacterial efficiency decreased with increasing ZnO nanofiller content, while AgNPs@ZnO/PU composite antibacterial efficiency increased with increasing AgNPs@ZnO nanofiller content. Also, the weak coordinate bond between ZnO and Ag in the PU chain extender was demonstrated. Increasing the ZnO content to 1.4 wt% resulted in greater Young’s modulus and tensile strength, which increased when the ZnO content was increased further. Such a dual-functional enhancement holds promise for applications requiring both antimicrobial efficacy and mechanical integrity.

Nitrogen-doped carbon quantum dots decorated ZnO nanorods array film for efficient UV photodetector applications

Nitrogen-doped carbon quantum dots decorated ZnO nanorods array film for efficient UV photodetector applications

Decorated ZnO nanorods with Bi2S3 nanosheets for enhanced photocatalytic removal of antibiotics and analgesics: Degradation mechanism and pathway

Novel nanorods (NRs) of Bi2S3-ZnO (BZ) heterojunction have been prepared using a microwave-assisted hydrothermal approach. The photocatalytic behavior of BZ heterojunction NRs has been investigated under simulated solar irradiation against the mineralization of meloxicam (MX) analgesics, sulfamethoxazole (SMX), trimethoprim (TMP) antibiotics, as well as crystal violet (CV) and malachite green (MG) dyes. XRD, FTIR, SEM, EDX, TEM, UV–Vis, BET, Zeta potential, and Pl techniques are used to characterize the prepared samples. The TEM results showed that the ZnO NRs are wrapped with Bi2S3 NSHs. For SMX and MX, the degradation rate of BZPCis 2.46 and 1.6 fold greater than that for pristine ZnO NRs, respectively. Furthermore, the BZ NRs heterojunction demonstrated 100% degradation efficiency for SMX, SM, TMP, and CV after 120 min, and after 60 min for MG. The enhanced photodegradation activity of BZ NRs photocatalyst (PC) is assigned to its high absorption ability for visible light, increased surface area, adsorption capability, as well as inhibition of the hole-electron recombination process according to the PL study. Furthermore, the quenching experiment exposed that hydroxyl radicals (·OH) exhibit a significant role in the photodegradation process.Moreover, after 5 cycles, the photocatalytic degradation efficiency of the BZ PC remained constant, confirming its high stability and reusability. The special charge transfer pathway over the BZ PC has been investigated, which will assistin the design of systems with superior photocatalytic properties. The degraded productsand pathwaysis also proposed.Conclusively, BZis considered stable, efficient, and non-selective PC for green solar-driven photocatalytic degradation.

MoSe2 nanoflakes decorated ZnO nanorods: An effective photoelectrode with S-scheme heterojunction for photoelectrocatalytic degradation of tetracycline and rhodamine B

Photoelectrocatalysis has been extensively used as one of the most widely known advanced oxidation processes (AOPs) owing to its superiority over photocatalytic systems with regards to the reduced recombination of charge carriers. ZnO demonstrates profound performance in PEC systems, and to overcome the obstacle of its limited visible light utilization, heterojunction formation of transition metal dichalcogenides (TMDs) with this classical semiconductor is proposed. Herein, MoSe2 was introduced onto ZnO nanorods to widen its visible light absorption and consequently boost the PEC ability of the proposed composite in omitting model organic contaminants in water. The as-synthesized nanocomposite was immobilized onto FTO by Electrophoretic deposition (EPD) technique which is then represented as the working electrode in the three-electrode PEC system. The characterization of the proposed nanocomposite was attained by techniques including: XRD, FESEM, FTIR, DRS and EDX. Moreover, electrochemical characterization was conducted to study its electrochemical properties. The PEC activity of the samples was studied by the degradation of Rhodamine B dye (62.3%) and tetracycline pharmaceutical (70.2%) under irradiation. The results indicated a much higher PEC ability for ZnO NR/MoSe2/FTO photoelectrode than its bare parent samples as well as its recyclability. To study the impact of the operational parameters, the electrolyte's concentration, initial pH, external bias voltage and initial concentration of the contaminant were investigated. By means of the scavenging tests, electrons and holes have the highest and the lowest importance in the PEC reaction, respectively. The S-scheme mechanism of degradation was proposed based on the cumulative experimental data.

Ag Nanoparticles Decorated ZnO Nanorods as Multifunctional SERS Substrates for Ultrasensitive Detection and Catalytic Degradation of Rhodamine B.

Industrial wastewater containing large amounts of organic pollutants is a severe threat to the environment and human health. Thus, the rapid detection and removal of these pollutants from wastewater are essential to protect public health and the ecological environment. In this study, a multifunctional and reusable surface-enhanced Raman scattering (SERS) substrate by growing Ag nanoparticles (NPs) on ZnO nanorods (NRs) was produced for detecting and degrading Rhodamine B (RhB) dye. The ZnO/Ag substrate exhibited excellent sensitivity, and the limit of detection (LOD) for RhB was as low as 10−11 M. Furthermore, the SERS substrate could efficiently degrade RhB, with a degradation efficiency of nearly 100% within 150 min. Moreover, it retained good SERS activity after multiple repeated uses. The interaction between Ag NPs, ZnO, and RhB was further investigated, and the mechanism of SERS and photocatalysis was proposed. The as-prepared ZnO/Ag composite structure could be highly applicable as a multifunctional SERS substrate for the rapid detection and photocatalytic degradation of trace amounts of organic pollutants in water.

Ultrafast chiral peptides purification via surface plasmon enhanced spin selectivity

By D-arginine and L-arginine chiral peptides induced spin selectivity and Au NPs enhanced spin polarization, chiral peptides purification has been effectively simplified and the purification performance has raised from a mixture system. The angular momentums of light are operated by the polarizer and wave plates. Au NPs decorated ZnO nanorods electrodes are utilized to modulate the polarization of spintronic. Seed growth methods are for synthesizing spherical Au NPs. UV light reduction methods are for urchin-liked Au NPs. Au NPs are decorated on ZnO nanorods electrodes for rising photon to electron conversion efficiency and enhancing spin polarization rates by surface plasmon effect. From our results, photon to the electron conversion efficiency of ZnO nanorods electrodes has effectively enhanced by urchin-liked Au NPs decorating. Ultrahigh localized plasmon conversion efficiency as high as 60% was also obtained. Besides, density functional theory (DFT) calculations simulated the force on spintronic. Since the D-arginine and L-arginine are on Au substrate, DFT results demonstrate different angular momentum and spin polarization coupling. Along with urchin-liked Au NPs rising chiral induced spin polarization by surface plasmon resonance, the sensitivity of chiral arginine has been raised around 5000% from bare ZnO nanorods electrodes. The purification and separation time of a specific chiral arginine only needs 5 min.

Highly sensitive NO2 gas sensor based on Ag decorated ZnO nanorods

Highly sensitive NO2 gas sensor based on Ag decorated ZnO nanorods

Effects of vertically aligned ZnO nanorods surface morphology on the ambient-atmosphere fabricated organic solar cells

The present study evaluates the effects of ZnO nanorods electron transport layer morphology synthesized using the low temperature chemical bath method on the performance of organic solar cells. The photoactive layers consisted of P3HT as electron donor and PCBM as electron acceptor. Two ZnO nanorods electron transport layers were studied, one with a smooth surface and a decorated surface. Well-defined ZnO nanorods with perfect hexagonal shapes could be synthesized by chemical bath deposition. Structural characterization confirmed that the vertically aligned ZnO nanorods were successfully obtained in pure form. Performance analysis revealed that the use of decorated ZnO nanorods increased the overall performance relative to the uncoated ZnO nanorods, attributed to the possible increase of light paths on the ZnO nanorods. The best device was obtained from annealed decorated ZnO nanorods ETL having PCE of 7.38%, Voc of 0.63 V, Jsc 18.44 mAcm−2 and FF of 0.60. Solar cells made from decorated ZnO nanorods ETL presented high Rsh of 1311.67 Ω.cm2 and 1497.23 Ωcm2 for as-synthesized and annealed ZnO ETL, respectively. In general, the strategy of decorating ZnO nanorods ETL is an important strategy to fabricate highly efficient organic solar cells and thus may have good potential for many other organic solar cells comprising other polymers apart from P3HT. Even though the efficiency obtained is low compared to the PCE achieved so far, this study gives the observation that may be possibly useful in the further improving PCE of already achieved high efficiencies.

Bi-functional carbon doped and decorated ZnO nanorods for enhanced pH monitoring of dairy milk and adsorption of hazardous dyes

This study demonstrates a simple and low-cost process for the in-situ doping and decoration of ZnO nanorods with carbon (CC–ZnO). In CC–ZnO, C-doping decreased the charge density (1.75 × 1018 cm−3) at the non-active sites of ZnO and decreased the charge transfer resistance (101 Ω) at the C-doped-ZnO/electrolyte interface by suppressing native defects and reducing the Schottky barrier height (–0.20 eV), respectively. Moreover, C-decoration enhanced the amphoteric performances of ZnO to react efficiently with H+ and OH− ions in an aqueous electrolyte, demonstrating a high pH sensitivity (48 mV/pH) and fast response time (7 s). Moreover, C-decoration enhanced the dispersion stability (92 h for 7.5 mg/mL concentration) and surface area (43.08 m2·g−1) of CC–ZnO in liquid phase, improving the monolayer adsorption capacity (119.40 mg/g) for the removal of rhodamine B (RhB) from aqueous solution. The optimum concentration and pH value of CC–ZnO and aqueous solution were determined to be 25 mg and 6.5, respectively, for maximum (84 %) removal of RhB in the initial five hours of reaction. Adsorption rate analysis revealed that CC–ZnO removed RhB through pseudo-second-order kinetics.

Wide-Linear Range Cholesterol Detection Using Fe2O3 Nanoparticles Decorated ZnO Nanorods Based Electrolyte-Gated Transistor

Electrolyte-gated transistor (EGT)-based biosensors are created with nanomaterials to harness the advantages of miniaturization and excellent sensing performance. A cholesterol EGT biosensor based on iron oxide (Fe2O3) nanoparticles decorated ZnO nanorods is proposed here. ZnO nanorods are directly grown on the seeded channel using a hydrothermal method, keeping in mind the stability of nanorods on the channel during biosensor measurements in an electrolyte. Most importantly, ZnO nanorods can be effectively grown and modified with Fe2O3 nanoparticles to enhance stability, surface roughness, and performance. The cholesterol oxidase (ChOx) enzyme is immobilized over Fe2O3 nanoparticles decorated ZnO nanorods for cholesterol detection. With cholesterol addition in buffer solution, the electro-oxidation of cholesterol on enzyme immobilized surface led to increased the biosensor’s current response. The cholesterol EGT biosensor detected cholesterol in wide-linear range (i.e., 0.1 to 60.0 mM) with high sensitivity (37.34 μA mM−1cm−2) compared to conventional electrochemical sensors. Furthermore, we obtained excellent selectivity, fabrication reproducibility, long-term storage stability, and practical applicability in real serum samples. The demonstrated EGT biosensor can be extended with changing enzymes or nanomaterials or hybrid nanomaterials for specific analyte detection.

CuO Nanoparticles Decorated ZnO Nanorods Based Extended-Gate Field-Effect-Transistor (EGFET) for Enzyme-Free Glucose Sensing Application.

In this work, CuO nanoparticles (NPs) decorated zinc oxide nanorods (ZnO NRs) on fluorine-doped tin oxide (FTO) substrate has been used as a working electrode. This working electrode has been used as an extended gate for field-effect transistor. The main objective is to use the EGFET (extended gate field effect transistor) as a glucose sensor. The proposed glucose sensor has good sensitivity of 6.643 mV/mM with a wide range of linearity (1mM-8mM) which covers the glucose level of human blood ranging from 4.4 mM to 6.6 mM. This novel concept of the glucose sensing using CuO NPs decorated ZnO nanorods based EGFET may be explored for sensing other saccharides such as mannose, fructose, and sucrose. This vertically grown ZnO nanorods decorated with CuO NPs based electrode gives reliable selectivity, good repeatability, and more stability. The performance of proposed sensor is also compared with commercially available glucose sensors. The sensitivity performance of the glucose sensor also confirms the capability to detect the glucose level from human blood and serum.

Photocatalytic degradation kinetics of cationic and anionic dyes using Au–ZnO nanorods: Role of pH for selective and simultaneous degradation of binary dye mixtures

Photocatalysis with ecofriendly and low cost materials is attractive for degradation of organic pollutants without aid of strong reagents. In this regard, Au nanoparticle decorated ZnO nanorods (Au–ZnO) with good crystalline quality was synthesized by cost-effective and scalable hydrothermal method followed by photo-reduction of Au salt. This study addresses variation of photocatalytic degradation kinetics of different nature of dyes with various scavengers and pH conditions. Further, the process versatility is demonstrated by selective or simultaneous degradation of binary dye mixtures with optimized parameters. From Langmuir-Hinshelwood kinetic model, dye concentration range for first order limiting case was determined, and further validated from measured surface area of photocatalyst and change in dye absorbance before irradiation. Better adsorption with faster degradation exhibited by Methylene Blue (MB) dye showed efficient mineralization, revealed from chemical oxygen demand measurements. In Au–ZnO photocatalysis, generation of hydroxyl radical and its significant role in dye degradation was demonstrated using different scavengers. Variation of dye adsorption with pH dependent surface charge characteristics of photocatalyst resulted about one order higher degradation rate constant of MB at high pH. Strong pH dependent MB degradation is shown to be useful for its selective or simultaneous degradation with other dyes. Results of this study are useful for designing photo-reactors and these nanoparticles are efficient for degradation of different dyes, their combinations and industrial effluents under low power UV lamp for treatment different organic pollutants.

Localized Energy Band Bending in ZnO Nanorods Decorated with Au Nanoparticles.

Surface decoration by means of metal nanostructures is an effective way to locally modify the electronic properties of materials. The decoration of ZnO nanorods by means of Au nanoparticles was experimentally investigated and modelled in terms of energy band bending. ZnO nanorods were synthesized by chemical bath deposition. Decoration with Au nanoparticles was achieved by immersion in a colloidal solution obtained through the modified Turkevich method. The surface of ZnO nanorods was quantitatively investigated by Scanning Electron Microscopy, Transmission Electron Microscopy and Rutherford Backscattering Spectrometry. The Photoluminescence and Cathodoluminescence of bare and decorated ZnO nanorods were investigated, as well as the band bending through Mott–Schottky electrochemical analyses. Decoration with Au nanoparticles induced a 10 times reduction in free electrons below the surface of ZnO, together with a decrease in UV luminescence and an increase in visible-UV intensity ratio. The effect of decoration was modelled with a nano-Schottky junction at ZnO surface below the Au nanoparticle with a Multiphysics approach. An extensive electric field with a specific halo effect formed beneath the metal–semiconductor interface. ZnO nanorod decoration with Au nanoparticles was shown to be a versatile method to tailor the electronic properties at the semiconductor surface.

Nitrogenated CQD decorated ZnO nanorods towards rapid photodegradation of rhodamine B: A combined experimental and theoretical approach

In this work, hybridization of nonmetal nitrogen-doped carbon dots (NCQDs) with ZnO nanorods (NRs) is utilized towards better photocatalytic degradation of rhodamine B under ultraviolet (UV) irradiation. The structural characterization is confirmed by XRD, XPS, FTIR and HRTEM measurements, while, optical properties have been investigated using UV–visible absorbance spectroscopy and photoluminescence study. The dye degradation using ZnO NR is recorded as ~69%, while the performance of ZnO/NCQD climbs up to ~90%, after nine minutes of UV irradiation. Furthermore, the reusability test suggests better stability of ZnO/NCQD than bare ZnO under photocorrosion. The cyclic voltammetry study confirms that the photoinduced electron-hole pairs originate from the heterojunction established between the interfaces of NCQD and ZnO. An insight on the photocatalytic excellence of ZnO/NCQD system is drawn from the density functional theory study. This indicates that appropriate band alignment of the heterostructure constituents is the key factor in this experimental attempt towards environment remedy.

Optimization of Ag2S Quantum Dots Decorated ZnO Nanorod Array Photoanodes for Enhanced Photoelectrochemical Performances

The synthesis of Ag2S quantum dots (QDs) deposited on the surface of electrodeposited ZnO nanorods (NRs) by a successive ionic-layer adsorption and reaction (SILAR) method is reported. A Box-Behnken response surface factorial design was used to organize the experiments conducted and identify the effects of three electrochemical parameters and their potential interactions. These parameters include zinc precursor concentration in the electrolytic bath, the electrolytic bath temperature and the electrodeposition time on the morphological and structural properties of the electrochemically grown ZnO nanorods. Morphological, structural and optical characterizations of these NRs heterojunctions were done. A direct band gap for Ag2S QDs, tuned between 2.54 and 2.73 eV by varying the SILAR cycle numbers, was determined. The presence of ZnO nanostructures increases the light scattering capability of the samples, allowing an important quantity of diffuse light near the absorption edge of Ag2S. The photoelectrochemical performance of these ZnO NRs decorated with Ag2S QDs based photoanodes has been evaluated. The SILAR parameters related to the growth of the Ag2S QDs that optimize the performance of this photoelectrode are presented. The effect of a ZnS passivation layer has been studied leading to an increase of about 400% in the short-circuit current density after passivation.

Organic/inorganic hybrid nanostructures of polycrystalline perylene diimide decorated ZnO nanorods highly enhanced dual sensing performance of UV light/CO gas sensors

Organic/inorganic hybrid nanostructures-based dual light-detecting/gas-sensing devices were fabricated. In this research, polycrystalline perylene diimide (PDI) membrane was coated on ZnO nanorods (NRs), functioning as sensing nanocomposites. Multiple material analyses including scanning electron microscope (SEM), energy dispersive spectrometer (EDS), high resolution transmission electron microscopy (HR-TEM), X-ray diffractometer (XRD), Raman spectroscopy, and confocal laser scanning microscopy (CLSM) indicate that organic perylene diimide was successfully deposited on ZnO NRs, forming organic/inorganic membrane on the sensing device. To examine the influence of organic/inorganic hybrid nanostructure on photo-sensing and gas-sensing behaviors, UV light detection and CO gas sensing impulse response were measured. Results reveal that organic/inorganic hybrid nanostructure can effectively enhance UV light and CO gas dual-sensing properties with addition of PDI. The coating of organic PDI on the ZnO NRs not only improves the gas interaction capability and gas-sensing stability but also enhances the UV absorption efficiency. Owing to advantages of low cost, simple fabrication, compact size, and device stability, hybrid PDI/ZnO organic/inorganic light/gas dual-sensing devices are promising for future portable hazardous light and gas sensing applications.

Photoelectrochemical performance of MWCNT–Ag–ZnO ternary hybrid: a study of Ag loading and MWCNT garnishing

Herein, by using chemical methods such as successive ionic layer adsorption and reaction (SILAR) and spin coating we have demonstrated a novel strategy for the synthesis of ternary hybrid to study photoelectrochemical (PEC) performance. To the best of our knowledge, for the first time we have represented a case study of achieving optimum SILAR cycles for Ag nanoparticles decoration on ZnO nanorods and a discussion was made on a role of multi-walled carbon nanotube (MWCNT) as a top layer over Ag–ZnO nanostructures for better PEC performance. Firstly, Ag nanoparticles loading over SILAR grown ZnO nanorods was varied for different SILAR cycles to optimize better photocurrent. This Ag–ZnO hybrid showed higher photocurrent density of 0.45 mA/cm2 at 1 V bias (vs SCE) and photoconversion efficiency (PCE) of 0.21% (0.45 V vs SCE). Thereafter, MWCNTs were garnished by using spin coating as a top layer on Ag–ZnO hybrid leading to the formation of ternary hybrid of MWCNT–Ag–ZnO for further enhancement of PEC activity. We believe that top layer of MWCNT plays a vital role of electron and hole transfer and bridges Ag decorated ZnO nanorods together leading to well-connected conducting pathways for efficient charge collection and transport. The appropriate band bending of MWCNT–Ag–ZnO hybrid leads to the formation of active interface helping out in charge separation leading to excellent photocurrent density of 0.56 mA/cm2 at 1 V bias (vs SCE) and photoconversion efficiency of 0.26% (0.45 V vs SCE). Enhanced light harvesting, higher donor density, appropriate band bending, lowest charge transfer radius of C–Ag–ZnO hybrid signifies that efficient charge transfer and restriction to charge recombination leading to the enhanced PEC performance.

ITO electrode modified with Pt nanodendrites-decorated ZnO nanorods for enzymatic glucose sensor

This work demonstrated the property enhancement of Pt nanodendrite (PtNDs)-decorated ZnO nanorods (ZnONRs) modified indium tin oxide (ITO) electrode for an enzymatic electrochemical glucose sensor. PtNDs with an average size of ~ 40 nm was synthesized via the chemical reduction method. The morphologies of the grown ZnONRs and decorated PtNDs/ZnONRs were observed by using a field-emission scanning electron microscope, whereas the presence of phases in the samples was studied by using an X-ray diffractometer. The electrochemical properties of the modified electrode were analyzed through cyclic voltammetry and amperometry, which showed that the presence of PtNDs contributed to a significant enhancement in the electron transfer rate during glucose redox reactions. The sensitivity obtained for the Nafion/GOx/PtNDs/ZnONRs/ITO electrode was 98.34 μA/mM cm2, which was higher than that obtained for the Nafion/GOx/ZnONRs/ITO electrode (15.71 μA/mM cm2). Moreover, the Nafion/GOx/PtNDs/ZnONRs/ITO electrode exhibited a low detection limit of 0.03 mM. The modified electrode had long-term stability and high selectivity against typical interfering species, such as uric acid and ascorbic acid. The reliability of the modified working electrode was studied by analyzing its performance in real human blood samples. The results showed the promising application of Nafion/GOx/PtNDs/ZnONRs/ITO as modified electrodes for electrochemical glucose sensors.

Core–shell hybrid structured rGO decorated ZnO nanorods synthesizedviaa facile chemical route with photosensitive properties

Two-dimensional graphene-based nanocomposites have gained much attention due to their promising applications in electronic and optoelectronic devices.