Zinc Oxide Nanoflowers Research Articles

Growth of high-density Zinc Oxide (ZnO) nanoflowers in all aqueous two-step method and their application in second harmonic generation of femtosecond laser

This study presents a novel two-step all aqueous solution method for the growth of high-density Zinc Oxide (ZnO) nanoflowers, utilizing ZnO powder as a precursor. For this, initially, a seed layer of ZnO nanostructures is prepared using a non-conventional sol-gel technique in an all-aqueous medium. Subsequently, high-density ZnO nanoflowers are synthesized on these seed layers through the chemical bath deposition method. Four samples, each with varying numbers of seed layers (ranging from one to four) are prepared and analyzed using field emission scanning electron microscopy (FESEM). FESEM results indicate that the sample with three seed layers exhibits optimized morphological characteristics. Consequently, further detailed investigation is conducted exclusively on this optimized sample. Furthermore, a preliminary study is done on second harmonic generation (SHG) of this optimized sample.

Cerium Enhanced Supercapacitive Properties of Zinc Oxide Nanoflowers

Cerium Enhanced Supercapacitive Properties of Zinc Oxide Nanoflowers

Impact of reduced-graphene-oxide functionalization of flower-like zinc-oxide nanostructures on sensing performance of resistive ethanol gas sensor

This research presents a sensitive resistive ethanol gas sensor based on reduced graphene oxide (rGO)-functionalized Zinc oxide nanoflowers (ZnO NFs). Upon completion of synthesis, the resulting nanostructures were cast onto the photolithographed silver interdigitated electrodes positioned on an Al2O3 substrate. The graphene oxide (GO) with a low oxidation degree was synthesized using a Hummer's method. In the pursuit of optimizing sensing performance, rGO-functionalized ZnO NFs were synthesized through a one-pot hydrothermal process, utilizing different initial quantities of GO (0 mg, 2 mg, 8 mg, and 12 mg). According to the gas sensing measurements, the fabricated sensor with 8 mg initial GO showed the highest response to ethanol at 250 °C. The results show that the GO addition reduced the optimal working temperature of the pure ZnO NFs from 350 °C to 250 °C. The sensor exhibited a good selectivity, repeatability, and high long-term stability. Enhanced ethanol sensing response of the optimized gas sensor was related to the formation of p-n heterojunction between p-type rGO (formed during hydrothermal process at 200 °C) and n-type ZnO and the presence of the optimal amount of rGO on the surface of NFs. The results obtained in this investigation stress the significance of pinpointing the optimal quantity of GO for producing rGO-ZnO nanoflowers with the highest possible sensitivity to ethanol gas.

Multiquenching-Based Aggregation-Induced Electrochemiluminescence Sensing for Highly Sensitive Detection of the SARS-CoV-2 N Protein.

The rapid epidemic around the world of coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus, proves the need and stimulates efforts to explore efficient diagnostic tests for the sensitive detection of the SARS-CoV-2 virus. An aggregation-induced electrochemiluminescence (AIECL) sensor was developed for the ultrasensitive detection of the SARS-CoV-2 nucleocapsid (N) protein in this work. Tetraphenylethylene doped in zeolite imidazole backbone-90 (TPE-ZIF-90) showed highly efficient aggregation-induced emission (AIE) to endow TPE-ZIF-90 with high ECL intensity. Upon the capture of the SARS-CoV-2 N protein by immune recognition, an alkaline phosphatase (ALP)-modified gold nanoparticle (AuNP)-decorated zinc oxide (ZnO) nanoflower (ALP/Au-ZnO) composite was introduced on the sensing platform, which catalyzed L-ascorbate-2-phosphate trisodium salt (AA2P) to produce PO43- and ascorbic acid (AA). Based on a multiquenching of the ECL signal strategy, including resonance energy transfer (RET) between TPE-ZIF-90 and Au-ZnO, disassembly of TPE-ZIF-90 triggered by the strong coordination between PO43- and Zn2+, and RET between TPE-ZIF-90 and AuNPs produced in situ by the AA reductive reaction, the constructed AIECL sensor achieved highly sensitive detection of the SARS-CoV-2 N protein with a low limit of detection of 0.52 fg/mL. With the merits of high specificity, good stability, and proven application ability, the present RET- and enzyme-triggered multiquenching AIECL sensor may become a powerful tool in the field of SARS-CoV-2 virus diagnosis.

Antibacterial Activity, Cell Wall Damage, and Cytotoxicity of Zinc Oxide Nanospheres, Nanorods, and Nanoflowers

Antibacterial Activity, Cell Wall Damage, and Cytotoxicity of Zinc Oxide Nanospheres, Nanorods, and Nanoflowers

Exploring Mo-ZnO@NF for hydrogen generation and methylene blue remediation: sunlight-driven catalysis

In this study, we elucidate the synthesis and characterization of molybdenum (Mo) doped zinc oxide (ZnO) nanoflowers (Mo-ZnO@NF) fabricated via a hydrothermal approach, showcasing their potential application in hydrogen generation and dye degradation. The successful synthesis of these nanoflowers is achieved through the deliberate incorporation of Mo ions into the ZnO lattice, yielding a distinctive hierarchical flower-like morphology. Comprehensive structural, morphological, and optical analyses are conducted employing a suite of analytical techniques, encompassing XRD, Raman, FESEM, and UV-Visible spectroscopy. XRD analysis confirms the retention of the hexagonal wurtzite crystal structure, accompanied by discernible peak shifts indicative of Mo ion integration. FESEM imaging further elucidates the flower-like architecture of Mo-ZnO, underscoring the intricate morphological features. Photocatalytic assessment reveals the remarkable efficacy of Mo-ZnO@NF, as evidenced by an unprecedented hydrogen evolution rate of 2024 mmol/h/g and 97% Methylene Blue (MB) dye degradation within a mere 40-minute timeframe. Furthermore, a comparative investigation between pristine ZnO and varying Mo doping concentrations (ranging from 1% to 5%) underscores the optimal doping concentration of 1% Mo in ZnO. This concentration threshold is shown to engender superior photocatalytic performance, potentially attributed to enhanced charge carrier separation and increased surface area conducive to catalytic reactions. Overall, this study not only advances our understanding of Mo-ZnO@NF nanostructures but also elucidates key insights into optimizing their photocatalytic efficacy for diverse environmental remediation applications.

Durable Antimicrobial Microstructure Surface (DAMS) Enabled by 3D-Printing and ZnO Nanoflowers.

A. Numerous studies have been trying to create nanomaterials based antimicrobial surfaces to combat the growing bacterial infection problems. Mechanical durability has become one of the major challenges to applying those surfaces in real life. In this study, we demonstrate the Durable Antimicrobial Microstructures Surface (DAMS) consisting of DLP 3D printed microstructures and zinc oxide (ZnO) nanoflowers. The microstructures serve as a protection armor for the nanoflowers during abrasion. The antimicrobial ability was tested by immersing in 2E8 CFU/mL Escherichia coli ( E. coli ) suspension and then evaluated using electron microscopy. Compared to the bare control, our results show that the DAMS reduces bacterial coverage by more than 90% after 12 hrs of incubation and approximately 50% after 48 hrs of incubation before abrasion. Importantly, bacterial coverage is reduced by approximately 50% after 2 min of abrasion with a tribometer, and DAMS remains effective even after 6 min of abrasion. These findings highlight the potential of DAMS as an affordable, scalable, and durable antimicrobial surface for various biomedical applications.

Enrichment of epoxy coating on amalgamation with corrosion-resistant poly (2,3-benzopyrrole)/zinc oxide nanoflowers (PBZNF) synthesized composite for carbon steel alloy featuring excellent hydrophobicity

Enrichment of epoxy coating on amalgamation with corrosion-resistant poly (2,3-benzopyrrole)/zinc oxide nanoflowers (PBZNF) synthesized composite for carbon steel alloy featuring excellent hydrophobicity

Design of a Humidity Sensor for a PPE Kit Using a Flexible Paper Substrate.

The present work reports the rapid sweat detection inside a PPE kit using a flexible humidity sensor based on hydrothermally synthesized ZnO (zinc oxide) nanoflowers (ZNFs). Physical characterization of ZNFs was done using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), UV-visible, particle size analysis, Raman analysis, and X-ray photoelectron spectroscopy (XPS) analysis, and the hydrophilicity was investigated by using contact angle measurement. Fabrication of a flexible sensor was done by deposition on the paper substrate using the spin coating technique. It exhibited high sensitivity and low response and recovery times in the humidity range 10-95%RH. The sensor demonstrated the highest sensitivity of 296.70 nF/%RH within the humidity range 55-95%RH, and the rapid response and recovery times were also calculated and found as 5.10/1.70 s, respectively. The selectivity of the proposed sensor was also analyzed, and it is highly sensitive to humidity. The humidity sensing characteristics were theoretically witnessed in terms of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and electronic properties of sensing materials in ambient and humid conditions. These theoretical results are evidence of the interaction of ZnO with humidity. Overall, the present study provides a scope of architecture-enabled paper-based humidity sensors for the detection of sweat levels inside PPE kits for health workers.

Co-sensitization of Copper Indium Gallium Disulfide and Indium Sulfide on Zinc Oxide Nanostructures: Effect of Morphology in Electrochemical Carbon Dioxide Reduction.

Recent advances in nanoparticle materials can facilitate the electro-reduction of carbon dioxide (CO2) to form valuable products with high selectivity. Copper (Cu)-based electrodes are promising candidates to drive efficient and selective CO2 reduction. However, the application of Cu-based chalcopyrite semiconductors in the electrocatalytic reduction of CO2 is still limited. This study demonstrated that novel zinc oxide (ZnO)/copper indium gallium sulfide (CIGS)/indium sulfide (InS) heterojunction electrodes could be used in effective CO2 reduction for formic acid production. It has been determined that Faradaic efficiencies for formic acid production using ZnO nanowire (NW) and nanoflower (NF) structures vary due to structural and morphological differences. A ZnO NW/CIGS/InS heterojunction electrode resulted in the highest efficiency of 77.2% and 0.35 mA cm-2 of current density at a -0.24 V (vs. reversible hydrogen electrode) bias potential. Adding a ZTO intermediate layer by the spray pyrolysis method decreased the yield of formic acid and increased the yield of H2. Our work offers a new heterojunction electrode for efficient formic acid production via cost-effective and scalable CO2 reduction.

Albumin-coated green-synthesized zinc oxide nanoflowers inhibit skin melanoma cells growth via intra-cellular oxidative stress

Zinc oxide (ZnO) has attracted a substantial interest in cancer research owing to their promising utility in cancer imaging and therapy. This study aimed to synthesized ZnO nanoflowers coated with albumin to actively target and the inhibit skin melanoma cells. We synthesized bovine serum albumin (BSA)-coated ZnO nanoflowers (BSA@ZnO NFs) and evaluated it's in vitro and in vivo therapeutic efficacy for skin cancer cells. BSA@ZnO NFs were prepared via single-step reduction method in the presence of plant extract (Heliotropium indicum) act as a capping agent, and further the successful fabrication was established by various physico-chemical characterizations, such as scanning electron microscopy (SEM), Fourier transform infra-red (FT-IR) spectroscopy, and x-rays diffraction (XRD) analysis. The fabricated BSA@ZnO NFs appeared flower like with multiple cone-shaped wings and average hydration size of 220.8 ± 12.6 nm. Further, BSA@ZnO NFs showed enhanced cellular uptake and cytocidal effects against skin cancer cells by inhibiting their growth via oxidative stress compared uncoated ZnO NFs. Moreover, BSA@ZnO NFs showed enhance biosafety, blood circulation time, tumor accumulation and in vivo tumor growth inhibition compared to ZnO NFs. In short, our findings suggesting BSA@ZnO NFs as a promising candidate for various types of cancer treatment along with chemotherapy.

ZnO Decorated Graphene-Based NFC Tag for Personal NO2 Exposure Monitoring during a Workday.

This paper presents the integration of a sensing layer over interdigitated electrodes and an electronic circuit on the same flexible printed circuit board. This integration provides an effective technique to use this design as a wearable gas measuring system in a target application, exhibiting high performance, low power consumption, and being lightweight for on-site monitoring. The wearable system proves the concept of using an NFC tag combined with a chemoresistive gas sensor as a cumulative gas sensor, having the possibility of holding the data for a working day, and completely capturing the exposure of a person to NO2 concentrations. Three different types of sensors were tested, depositing the sensing layers on gold electrodes over Kapton substrate: bare graphene, graphene decorated with 5 wt.% zinc oxide nanoflowers, or nanopillars. The deposited layers were characterized using FESEM, EDX, XRD, and Raman spectroscopy to determine their crystalline structure, morphological and chemical compositions. The gas sensing performance of the sensors was analyzed against NO2 (dry and humid conditions) and other interfering species (dry conditions) to check their sensitivity and selectivity. The resultant-built wearable NFC tag system accumulates the data in a non-volatile memory every minute and has an average low power consumption of 24.9 µW in dynamic operation. Also, it can be easily attached to a work vest.

Synthesis of zinc oxide nanoflower using egg shell membrane as template

In this study, the nanocomposite of eggshell membrane is synthesized with ZnO by the chemical bath deposition (CBD) method, and eggshell membrane, which is used as a template, and decomposed. The end product obtained is nanoflowers of zinc oxide (ZnFs). The petals of nanoflowers obtained are of hexagonal cross-section similar to the unit cell structure of zinc oxide. The CBD parameters of temperature, reaction time, and solution pH were varied extensively during this study to obtain optimized parameters for the growth of ZnFs. The obtained nanoflower structure was analyzed using various characterization techniques of Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), X-Ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR).

Green synthesis of silver and copper-doped zinc oxide nanoflowers using Leucophyllum frutescens leaf extract for photodegradation of methylene blue dye and antibacterial applications

This is the first report on biogenic synthesis of silver and copper-doped zinc oxide nanoflowers using Leucophyllum frutescens leaf extract for environmental and biomedical applications.

Systematic exploration of defect-rich 2D nanopetal assembled 3D ZnO nanoflowers for improved photocurrent generation and photocatalytic performance

Zinc Oxide (ZnO) stands as a highly significant metal oxide semiconductor with a large band gap of (3.2 eV), showcasing multifaceted properties. Significant findings of this study, designate the successful fabrication of 3D nanoflowers (NFs) with a specialized ZnO nanoarchitecture through a facile polyol process, considered by a notable presence of defect sites, as a photocatalyst for the deterioration of Rhodamine B (RhB). All ZnO NFs display increased absorption and a distinctive shift towards longer wavelengths, indicating a red shift phenomenon. Raman scattering, photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and electron spin resonance (EPR) unveiled that, the ZnO/24 hr, exhibited a notable abundance of defect states. The Brauner–Emmett–Teller (BET) analysis shows surface area of 55.14 m2g−1 for ZnO/24 hr resulted in a subsequent augmentation of the concentration of surface defects potentially enhancing the RhB photodegradation efficiency of 98%, surpassing the performance of other ZnO NFs samples, with a kinetic rate of 0.0638 min–1 under sunlight irradiation and better photocurrent response that improves the photogenerated separation of charge carriers. Hence, the findings from this investigation will offer novel perspectives for enhancing the photocatalytic and photoelectrochemical attributes of ZnO NFs grown over different durations.

Microwave-assisted synthesis of zinc oxide nanoflowers for improving the rheological and filtration performance of high-temperature water-based drilling fluids

Zinc Oxide (ZnO) nanostructures have proved useful across a wide range of applications like medical technology, electronics, sulfur removal as well as microbial growth control. In the petroleum industry, ZnO nanostructures have been widely researched for application in Drilling Fluids. ZnO has been previously reported to work excellently in enhancing the electrical and thermal properties of water-based drilling fluids (WBDFs). However, the role of morphological features of the nanostructures in influencing the properties of bentonite-laden WBDFs is less understood. In this work, ZnO nanostructures were synthesized under microwave irradiation which resulted in different shapes like rods and flowers. The effect of microwave power and time was observed with Field Emission Scanning Electron Microscopy (FE-SEM) and Dynamic Light Scattering (DLS), and a suitable synthesis criterion was selected for achieving the smallest complex ZnO nanoflowers. These nanoflowers were further characterized for functional group and structural identification. Bentonite/Polymer Nanofluids were prepared and tested for properties like rheology, API, and HPHT filtration before and after thermal aging at 150 °C. The results show ZnO nanoflowers in WBDFs have excellent filtration control ability with ∼56% reduction in HPHT filtrate volume and can impart a flat-line rheological profile. Also, the breaking of nanoflowers into smaller nanorods and some further textural changes is predicted to enhance the stability of the WBDFs due to better dispersion and compact mud cake formation. The study shows that the morphological features of metal oxide nanostructures can be controlled with microwave irradiation and play an effective role in controlling the properties of bentonite/polymer WBDFs.

Hydrangea-like AuPtRu/ZnO-rGO Nanocomposites with Enhanced Peroxidase Mimiking Activity for Senitive Colorimetric Determination of H2O2.

In this study, a facile and cost-effective hydrothermal synthesis method was used to synthesize zinc oxide nanoflowers modified by reduced graphene oxide, and subsequently, trimetallic AuPtRu nanoparticles(AuPtRuNPs) were supported via the reduction method for high-sensitivity colorimetric detection of H2O2 in weakly acidic solutions. Compared to monometallic and bimetallic nanoparticles, trimetallic nanoparticles exhibit significant synergistic effects and enhanced catalytic activity. After providing a three-dimensional structure with multiple pores by zinc oxide and enhancing electron transfer ability by reduced graphene, the trimetallic nanocomposites (AuPtRu/ZnO-rGO) exhibited excellent peroxidase-mimicking activity, which can effectively catalyze 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue oxidation product (oxTMB) in the presence of H2O2. Compared to horseradish peroxidase (HRP), AuPtRu/ZnO-rGO demonstrated significantly enhanced catalytic velocity (Vmax = 6.16 × 10-8 M/s) and affinity (Km = 0.02) for H2O2. The study of the catalytic mechanism showed that trimetallic Au, Pt, and Ru could effectively catalyze H2O2 to produce hydroxyl radicals (•OH) to accelerate the oxidation of TMB and enhance the peroxidase-mimicking activity of the AuPtRu/ZnO-rGO nanocomposites. The results showed that the as-synthesized hydrangea-like AuPtRu/ZnO-rGO nanocomposites showed enhanced peroxidase-mimicking activity. It could be used for the colorimetric detection of H2O2 in the range 5-1000 μM with a LOD of 3.0 μM (S/N = 3), and the recoveries are 93.0-101.7%. In addition, the AuPtRu/ZnO-rGO nanocomposites have good applicability for sensitive colorimetric determination of H2O2 in milk, and it has broad application prospects as a multifunctional sensing platform in the food processing industry.

Power enhancement of piezoelectric energy harvester using ZnOnf-PDMS composite with PVDF filler

This work aims to fabricate a piezoelectric energy harvester using Polydimethylsiloxane (PDMS) with Zinc Oxide nanoflower (ZnOnf) and Poly(vinylidene fluoride) (PVDF). ZnOnf is synthesised via the hydrothermal method by varying the reaction time. The long nanoflowers resulting from the reaction time of 2 h are utilized to prepare the piezoelectric composite. Two energy harvesters are fabricated: ZnOnf-PDMS (ZP) and ZnOnf-PVDF-PDMS (ZPP), to harvest mechanical energy. The incorporation of PVDF into the ZnOnf-PDMS composite enhances the active polar β-phase of PVDF, leading to improved piezoelectric activity. The output voltage of the piezoelectric harvesters is measured under various impact forces applied using a self-designed impact force setup. The addition of PVDF to the ZnOnf-PDMS composite results in an increase in the dielectric constant and, consequently, in the energy harvester's output. Thus, at an applied impact force of 2.64 N, the output power harvested is 11.4 µW for ZP, and is amplified to 14.27 µW for ZPP. Furthermore, the incorporation of PVDF enhances the thermal stability and delays the decomposition temperature of the energy harvester.

Doxorubicin loaded zinc oxide nanoflowers – Surmounting drug-induced toxicity

Doxorubicin (DOX) induces cardiotoxicity, hepatotoxicity and nephrotoxicity, through multiplicity of mechanisms involving the production of free radicals causing oxidative stress and apoptosis. Zinc oxide (ZnO) nanomaterials, besides biocompatibility and biodegradability, also show the protective effect on cells and organs. The current study aspires to delve into the protective effects of ZnO in DOX-loaded ZnO nanoflowers (DOX-ZnO-NFs). Comparative in-vitro toxicities of DOX, blank zinc oxide nanoflowers (ZnO-NFs) and DOX-ZnO-NFs were examined against in-vitro normal Henrietta Lacks (HeLa) cell line and in-vivo in the Wistar rats. The change in body weight, hematological parameters and biochemical biomarkers of heart, kidney and liver and histopathology of tissues were examined at 24 h and after 14 days post dosing of the test moieties. DOX-ZnO-NFs portrayed biocompatibility and safety in the HeLa cells and the kidneys, liver and heart of Wistar rats. At 30 μg/ml, DOX-ZnO-NFs showed 72.53 ± 0.39% cell survival rate, relative to 80.59 ± 0.99% by ZnO-NFs and 13.8 ± 0.22%, by DOX. DOX-ZnO-NFs and ZnO-NFs caused slight change in organ's weight, minimum haemolysis, little effect on liver and kidney enzymes, improved activity of antioxidant enzymes and maintained tissues' architecture relative to the bare DOX. The drug-free ZnO-NFs with the maximum safety supported the protective effect of ZnO and, thus DOX-ZnO-NFs surmounted the DOX-induced systemic toxicity.

Zinc oxide nano-flowers improve the growth and propagation of mulberry cuttings grown under different irrigation regimes by mitigating drought-related complications and enhancing zinc uptake

Silkworm larvae mainly consume mulberry leaves; therefore, mulberry cultivation is important for the production of raw silk. Drought stress and micronutrient deficiency (Zn) are known to affect the propagation of mulberry cuttings. In this purview, the current investigation attempted to inspect the efficacy of different concentrations of zinc oxide nano-flower (ZnNFs) applied through both soil admixture and foliar spray on the propagation of mulberry cuttings grown under deficit irrigation regimes. The overall results demonstrated that the ZnNF-treated plant cuttings were well-adapted to drought stress and performed better in comparison to the control set. Out of the tested concentrations – ZnNF-10 (applied as 10 mg/kg soil and 10 ppm as foliar spray thrice) was found to be optimum, showing relatively better initial root establishment, the emergence of leaves, and survival and sprouting percentage. Further studies also confirmed an improvement in the accumulation of photosynthetic pigments, carbohydrates, and protein content even under extreme drought conditions. Most importantly, the ZnNF-10 treatment contributed to ROS detoxification and cell membrane protection by enhancing the pool of antioxidant enzymes. The study further demonstrated that ZnNF-10 application enhanced zinc content by 147.50%, 179.49%, and 171.99% in root, shoot, and leaves of the treated cuttings; thereby, improving the bioaccumulation factor of the plant parts. All of these interactive phenomena led to an increment in shoot height, biomass, leaf area, and leaf number of cuttings. These findings, therefore, indicated that ZnNFs can be developed as a promising nano-fertilizer for mulberry growth facilitating Zn uptake and mitigation of drought-induced complications.