Structure Of Nanoflakes Research Articles

2LiBH4-MgH2 System Catalytically Modified with a 2D TiNb2O7 Nanoflake for High-Capacity, Fast-Response, and Long-Life Hydrogen Energy Storage.

To achieve large-scale hydrogen storage for growing high energy density and long-life demands in end application, the 2LiBH4-MgH2 (LMBH) reactive hydride system attracts huge interest owing to its high hydrogen capacity and thermodynamically favorable reversibility. The sluggish dehydrogenation kinetics and unsatisfactory cycle life, however, remain two challenges. Herein, a bimetallic titanium-niobium oxide with a two-dimensional nanoflake structure (2D TiNb2O7) is selected elaborately as an active precursor that in situ transforms into TiB2 and NbB2 with ultrafine size and good dispersion in the LMBH system as highly efficient catalysts, giving rise to excellent kinetic properties with long-term cycling stability. For the LMBH system added with 5 wt% 2D TiNb2O7, 9.8 wt% H2 can be released within 20 min at 400 °C, after which the system can be fully hydrogenated in less than 5 min at 350 °C and 10 MPa H2. Moreover, a dehydrogenation capacity of 9.4 wt% can be maintained after 50 cycles corresponding to a retention of 96%, being the highest reported to date. The positive roles of TiB2 and NbB2 for kinetics and recyclability are from their catalytic nucleation effects for MgB2, a main dehydrogenation phase of LMBH, thus reducing the apparent activation energy, suppressing the formation of thermostable Li2B12H12 byproducts, and inhibiting the hydride coarsening. This work develops an advanced LMBH system, bringing hope for high-capacity, fast-response, and long-life hydrogen energy storage.

Coordination Compound Guided a Novel Composite Film with Zn2V2O7 Nanoflake and VO2@Zn2V2O7 Nanoparticle for Enhanced Thermochromism Smart Window.

Thermochromic vanadium dioxide (VO2) can intelligently modulate the transmittance of indoor solar radiation to reduce the energy consumption of air conditioning in buildings. Nevertheless, it remains a great challenge to simultaneously improve the luminous transmittance (Tlum) and solar modulation ability (ΔTsol) of VO2. In this study, a novel approach is employed utilizing a coordination compound to finely tune the growth of a VO2 based composite film, yielding a hierarchical film comprising Zn2V2O7 nanoflakes and VO2@Zn2V2O7 core-shell nanoparticles. Remarkably, the resulting composite films showcase exceptional optical performance, achieving a Tlum of up to 73.0% and ΔTsol of 15.7%. These outcomes are attributed to the antireflection properties inherent in the nanoflake structure and the localized surface plasmon resonance of well-dispersed VO2 nanoparticles. In addition, the Zn2V2O7-VO2 film demonstrates remarkable environmental durability, retaining 90% of its initial ΔTsol even after undergoing aging at 100°C under 50% relative humidity for a substantial period of 30 days - a durability equivalent to ≈20 years under ambient conditions. This work not only achieves a harmonious balance between Tlum and ΔTsol but also introduces a promising avenue for the design of distinctive composite nanostructures.

Binder-free copper manganese sulfide nanoflake arrays electrodeposited on reduced graphene oxide-wrapped nickel foam as an efficient battery-type electrode for asymmetric supercapacitors

In the current study, 2D interconnected copper manganese sulfide (CMS) nanoflake arrays are successfully electrodeposited on nickel foam (NF) and reduced graphene oxide-coated NF (NF/rGO). A pulsed current electrodeposition method is used to prepare a uniform and homogeneous coverage of rGO on NF. By using rGO as a conductive carbon-based template, an ultrathin nanoflake structure of CMS with smaller dimensions and higher electrochemically active surface area (ECSA) is achieved. The results reveal the battery-type behavior of the as-synthesized CMS electroactive materials. At a current density of 5 A g−1 this electrode delivers a significant specific capacity of 667 C g-1 and maintained a considerable proportion of its initial capacity, with a retention value of 83.2 % even after undergoing 3000 charge/discharge cycles. In addition, an asymmetric supercapacitor is fabricated by setting up the synthesized NF/rGO/CMS sample as the positive electrode and activated carbon as the negative electrode. The constructed device not only delivers an impressive energy density of 63.3 Wh kg-1 accompanied by an outstanding power density of 11214.5 W kg−1, but also exhibits a considerable cycling durability, enduring only a 12 % decline in specific capacitance after 3000 charge/discharge cycles at a current density of 5 A g−1.

Optimizing the defect engineering of MnCo2O4 spinel structure through Zn-substitution as a cathode for high-performance Zinc-ion batteries

Zinc-ion batteries are regarded as an effective alternative for energy storage because of their low flammability, affordability, inherent safety, and high theoretical capacity. However, manganese-based materials are limited due to a relatively narrow tunneling pathway, causing low-rate capacity and low life cycle stability. Hence, an effective strategy using defect-engineered crystal structure promoted by Zn-substituted MnCo2O4 to achieve a high-performance ZIB is proposed. The microspheres, assembled with interconnected micro- and nanoflake structures of ZnxMn1-xCo2O4 (with the Zn-substitution of x = 0, 0.2, 0.4, 0.6, and 0.8), are hydrothermally synthesized, followed by calcination, which serves as the cathode for ZIBs. At the optimal Zn0.4Mn0.6Co2O4 cathode, ZIBs battery possesses a superior discharged specific capacity of 660 mAh g-1 at 0.05 A g-1, a high-rate performance (energy density of 260–528 Wh kg−1 at a power density of 800–40 W kg−1), and good capacity retention of 70 mAh g-1 after 800 cycles at 0.2 A g–1. Ex-situ SEM-EDX and XPS results through charge/discharge cycles confirm the high stability and reversibility of Zn0.4Mn0.6Co2O4 in its electron state. Such improved rate capacity and long-life cycles originate from efficient defect engineering using Zn-substitution and oxygen vacancies. These lead to improved ion insertion and Zn2+ transport kinetics, along with enhanced electrical conductivity, resulting in the reversibility reactions of Mn4+/Mn2+ and Co2+/Co3+ upon Zn2+insertion/extraction.

Low-Intensity Light Detection with a High Detectivity Using 2D-Sb2Se3 Nanoflakes on 1D-ZnO Nanorods as Heterojunction Photodetectors.

Multifunctional photodetectors (PDs) with broadband responsivity (R) and specific detectivity (D*) at low light intensities are gaining significant attention. Thus, we report a bilayer PD creatively fabricated by layering two-dimensional (2D) Sb2Se3 nanoflakes (NFs) on one-dimensional (1D) ZnO nanorods (NRs) using simple thermal transfer and hydrothermal processes. The unique coupling of these two layers of materials in a nanostructured form, such as 2D-Sb2Se3 NFs/1D-ZnO NRs, provides an effective large surface area, robust charge transport paths, and light-trapping effects that enhance light harvesting. Furthermore, the combination of both layers can effectively facilitate photoactivity owing to proper band alignment. The as-fabricated device demonstrated superior overall performance in terms of a suitable bandwidth, good R, and high D* under low-intensity light, unlike the single-layered 1D-ZnO NRs and 2D-Sb2Se3 NF structures alone, which had poor detectivity or response in the measured spectral range. The PD demonstrated a spectral photoresponse ranging from ultraviolet (UV) to visible (220-628 nm) light at intensities as low as 0.15 mW·cm-2. The PD yielded a D* value of 3.15 × 1013 Jones (220 nm), which reached up to 5.95 × 1013 Jones in the visible light region (628 nm) at a 3 V bias. This study demonstrated that the 2D-Sb2Se3 NFs/1D-ZnO NRs PD has excellent potential for low-intensity light detection with a broad bandwidth, which is useful for signal communications and optoelectronic systems.

Defects engineering of nickel tellurium electrocatalyst to boost urea oxidation reaction: Electrodeposition mechanism and performance

The urea oxidation reaction (UOR) offers an attractive strategy to replace the oxygen evolution reaction (OER) for energy-saving hydrogen production due to its favorable thermodynamic property, but its development is hindered by the lack of efficient and cost-effective electrocatalysts. In this study, nickel-tellurium (Ni-Te) grown on 3D nickel foam was successfully synthesized using a simple and facile electrodeposition method. The electrodeposition process of Ni-Te follows the three-dimensional instantaneous nucleation/growth mechanism controlled by diffusion. The apparent activation energy (Ea) of Ni-Te in the electrodeposition process is as low as 36.5 kJ∙mol-1. Lattice distortion structure obtained by electrodeposition modifies the intrinsic electronic structure and optimizes the adsorption energy of intermediates. Thanks to the synergistic effects of fast electron transport, superhydrophilic surface and nanoflake structure, the prepared Ni-Te electrocatalyst shows excellent activity toward UOR with a low potential of 1.503 V vs. RHE at 100 mA·cm-2 and a small Tafel slope (63.6 mV·dec-1) in 1.0 M KOH containing 0.33 M urea solution.

Fabrication of pure Bi2WO6 and Bi2WO6/MWCNTs nanocomposite as potential antibacterial and anticancer agents

An essential research area for scientists is the development of high-performing, inexpensive, non-toxic antibacterial materials that prevent the transfer of bacteria. In this study, pure Bi2WO6 and Bi2WO6/MWCNTs nanocomposite were prepared by hydrothermal method. A series of characterization results by using XRD FTIR, Raman, FESEM, TEM, and EDS analyses, reveal the formation of orthorhombic nanoflakes Bi2WO6 by the addition of NaOH and pH adjustment to 7. Compared to pure Bi2WO6, the Bi2WO6/MWCNTs nanocomposite exhibited that CNTs are efficiently embedded into the structure of Bi2WO6 which results in charge transfer between metal ion electrons and the conduction or valence band of Bi2WO6 and MWCNTs and result in shifting to longer wavelength as shown in UV–visible and PL. The results confirmed that MWCNTs are stuck to the surface of the microflowers, and some of them embedded inside the Bi2WO6 nanoflakes without affecting the structure of Bi2WO6 nanoflakes as demonstrated by TEM. In addition, Pure Bi2WO6 and the Bi2WO6/MWCNTs nanocomposite were tested against P. mirabilis and S. mutans., confirming the effect of addition MWCNTs materials had better antibacterial activity in opposition to both bacterial strains than pure Bi2WO6. Besides, pure Bi2WO6 and the Bi2WO6/MWCNTs nanocomposite tested for cytotoxicity against lung MTT test on Hep-G2 liver cancer cells, and flow-cytometry. Results indicated that pure Bi2WO6 and the Bi2WO6/MWCNTs nanocomposite have significant anti-cancer efficacy against Hep-G2 cells in vitro. In addition, the findings demonstrated that Bi2WO6 and Bi2WO6/MWCNTs triggered cell death via increasing ROS. Based on these findings, it appears that pure Bi2WO6 and the Bi2WO6/MWCNTs nanocomposite have the potential to be developed as nanotherapeutics for the treatment of bacterial infections, and liver cancer.

Cyrene- and water-based exfoliation of black phosphorus for potential nanolayer-mediated disaggregation of insulin fibrils

Liquid suspensions of phosphorene nanolayers (2D-bP) obtained through liquid phase exfoliation (LPE) of elemental black phosphorus (bP) have been prepared and extensively characterized. The exfoliating ability of deionized water (DI water), dihydrolevoglucosenone, (Cyrene), and N-methyl-2-pyrrolidone (NMP) has been investigated and compared along with the differences in the structure, concentration, and stability of the collected nanoflakes. Water was chosen as an exfoliating medium due to its harmlessness and cost-effectiveness and because it is the safest solvent for further potential biomedical applications. Cyrene is a new bio-based solvent still under study. NMP, which is among the most widely used solvents for the exfoliation of 2D systems including bP, has been employed for comparison. The obtained suspensions have been characterized by Dynamic Light Scattering (DLS), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Phosphorus 31 Nuclear Magnetic Resonance (31P NMR), Transmission Electron Microscopy (TEM), Ultraviolet -Visible (UV–Vis), and Raman spectroscopies. The stability of 2D-bP suspensions over time and their photoactivity, i.e., their ability to generate singlet oxygen species as a photosensitizer, have been investigated. The collected results evidenced that the exfoliation of bP in different solvents, including DI water, resulted in satisfactory and comparable nanoflake structures and features. The singlet oxygen generation through irradiation of 2D-bP in DI water suspensions, advantageously obtained directly from LPE, showed promising potential for use in photodynamic therapy (PDT). Preliminary data on the potential biomedical application of 2D-bP to inhibit the insulin self-assembly into amyloid aggregates as well as to cause fibrils disassembling through simple incubation or photoactivity, are also discussed.

Enhanced oxygen evolution of a new copper-based metal-organic framework through the construction of a heterogeneous structure with bismuth oxyiodide

Herein, a newly developed MOF, Cu-based on 2-amino terephthalic acid (CuATPA) is successfully prepared and utilized as a photoanode material. To achieve high-efficiency electron/hole separation and rapid catalytic kinetics, a heterojunction architecture is designed by combining CuATPA with BiOI. Scanning electron microscopy images reveal the formation of CuATPA nanoplates within the structures of BiOI nanoflakes. Electrochemical characterization demonstrates the excellent photoelectrocatalytic performance of the CuATPA-BiOI nanocomposite. Linear sweep voltammetry reveals a reduced overpotential value for the CuATPA-BiOI nanocomposite, indicating enhanced catalytic activity. Moreover, the CuATPA-BiOI photoanode displays a photo-voltage of 0.43 V compared to 0.23 and 0.24 V for the CuATPA and BiOI photoanodes, respectively, indicating a deeper band bending. The improved photoelectrochemical performance of the nanocomposite is attributed to efficient separation and transfer of photo-generated charge carriers, as evidenced by higher charge density extracted from the Mott-Schottky plot and smaller semicircle radius in the Nyquist plot.

Impact of annealing temperature on praseodymium cerium telluride nanoparticles synthesise via hydrothermal approach for optoelectronic application

ABSTRACT In this paper, we use hydrothermal technique to synthesise the nanoparticle of praseodymium, cerium telluride (Pr0.2Ce0.5Te0.2) using 0.2 mol of praseodymium (III) oxide (Pr2O3), and 0.5 mol of cerium (III) nitrate hexahydrate (Ce(NO3)3.6 H2O) and 0.2 mol of Te(NO3)4and evaluate how varying annealing temperature influences the material’s optical, structure, morphology, and electrical characteristics. The XRD pattern reveals a polycrystalline structure with 2theta angle of 8.418°, 9.644°, 11.037°, 13.824°, 16.442°, 19.151°, 22.262°, 40.938°. Corresponding to the diffraction peaks (011), (012), (111), (121), (114), (200), (211), (311) it was observed that the praseodymium cerium telluride nanoparticles display a significant nanoflake structure. It was observed that the size of the large nanoflakes decreased. When subjected to annealing, the surface energy of the material increased due to the presence of nanoparticle clusters. The nanoparticle that underwent annealing at 400°C was found to be more susceptible to agglomeration due to the strains that resulted from the high-temperature treatment. Praseodymium cerium telluride is highly absorbent, especially in the ultraviolet and blue light ranges. The unannealed praseodymium cerium telluride nanoparticles have a bandgap energy of 2.75 eV, which is observed to narrow down to a range of 2.61–2.37 eV as the temperature for annealing is increased.

High Areal Capacity FeS@Fe Foam Anode with Hierarchical Structure for Alkaline Solid‐State Energy Storage

AbstractThe development of low‐cost and high‐performance iron (Fe)‐based anode materials is of great significance for rechargeable aqueous batteries. Herein, a FeS@Fe foam anode with crosslinked nanoflake array structure is fabricated. Being adopted as alkaline anode, FeS@Fe foam delivers enhanced areal capacity of 31.1 mAh cm−2 (at 50 mA cm−2), which is ≈1.5 times that of the‐state‐of‐the‐art literatures. The scaled‐up tests further reveal the higher capacity (800.7 mAh) and current density (1.25 A) with the area of 25 cm2. The FeS@Fe foam anode sustains intact after 270‐day cycles, demonstrating excellent durability. The assembled FeS//NiO single battery provides a superior areal energy density of 300.7 Wh m−2 at 500 W m−2. The reaction mechanism and electrode kinetics are revealed by combining in/ex situ techniques and DFT calculations. Experimental results and in/ex situ characterizations validate that excellent structural stability and high areal capacity are attributed to effective interface regulation and improved energy storage mechanism, respectively. This work pushes the advanced Fe‐based electrode to a superior level among these available alkaline solid‐state batteries.

Bacterial Surface Appendages Modulate the Antimicrobial Activity Induced by Nanoflake Surfaces on Titanium.

Bioinspired nanotopography is a promising approach to generate antimicrobial surfaces to combat implant-associated infection. Despite efforts to develop bactericidal 1D structures, the antibacterial capacity of 2D structures and their mechanism of action remains uncertain. Here, hydrothermal synthesis is utilized to generate two 2D nanoflake surfaces on titanium (Ti) substrates and investigate the physiological effects of nanoflakes on bacteria. The nanoflakes impair the attachment and growth of Escherichia coli and trigger the accumulation of intracellular reactive oxygen species (ROS), potentially contributing to the killing of adherent bacteria. E. coli surface appendages type-1 fimbriae and flagella are not implicated in the nanoflake-mediated modulation of bacterial attachment but do influence the bactericidal effects of nanoflakes. An E. coli ΔfimA mutant lacking type-1 fimbriae is more susceptible to the bactericidal effects of nanoflakes than the parent strain, while E. coli cells lacking flagella (ΔfliC) are more resistant. The results suggest that type-1 fimbriae confer a cushioning effect that protects bacteria upon initial contact with the nanoflake surface, while flagella-mediated motility can lead to elevated membrane abrasion. This finding offers a better understanding of the antibacterial properties of nanoflake structures that can be applied to the design of antimicrobial surfaces for future medical applications.

Silicon‐Doped Graphene as a Catalyst for Hydrogenation of Carbon Dioxide: A Molecular Simulation Study

AbstractThe catalytic effect of Si‐doped graphene nanoflakes (NFs) on CO2 reduction with molecular hydrogen was explored theoretically at the TPSS/def2‐SVP+D3BJ level of theory. Substituting carbon with silicon generates defects in the NF structure, which leads to a polyradical ground state of the NF. The silicon defect enhances the reactivity towards the substrates. Si‐doped graphene NFs exhibit higher catalytic activity for CO2 reduction to formic acid than silicene. Notably, Si‐doped graphene favors formic acid over carbon monoxide, which is similar to silicene. Formic acid to formaldehyde and formaldehyde to methanol conversions have also been studied, sometimes showing improved efficacy of Si‐doped graphene over silicene. The final reduction step, the methanol to methane reaction, occurs in four steps, with the rate‐determining step involving hydrogen transfer from silicon to methyl, whose activation energy is lower than that of silicene. Si‐doped graphene NFs act as better catalysts with lower activation energies than those of silicene. Overall, silicon‐doped graphene enhanced the catalytic activity while maintaining the environmental stability of the graphene.

Facile synthesis of nanoparticles-stacked Co3O4 nanoflakes with catalase-like activity for accelerating wound healing.

Delayed wound healing caused by excessive reactive oxygen species (ROS) remains a considerable challenge. In recent years, metal oxide nanozymes have gained significant attention in biomedical research. However, a comprehensive investigation of Co3O4-based nanozymes for enhancing wound healing and tissue regeneration is lacking. This study focuses on developing a facile synthesis method to produce high-stability and cost-effective Co3O4 nanoflakes (NFs) with promising catalase (CAT)-like activity to regulate the oxidative microenvironment and accelerate wound healing. The closely arranged Co3O4 nanoparticles (NPs) within the NFs structure result in a significantly larger surface area, thereby amplifying the enzymatic activity compared to commercially available Co3O4 NPs. Under physiological conditions, it was observed that Co3O4 NFs efficiently break down hydrogen peroxide (H2O2) without generating harmful radicals (·OH). Moreover, they exhibit excellent compatibility with various cells involved in wound healing, promoting fibroblast growth and protecting cells from oxidative stress. In a rat model, Co3O4 NFs facilitate both the hemostatic and proliferative phases of wound healing, consequently accelerating the process. Overall, the promising results of Co3O4 NFs highlight their potential in promoting wound healing and tissue regeneration.

Zn-doped NiMoO4 enhances the performance of electrode materials in aqueous rechargeable NiZn batteries.

In this work, zinc was introduced to prepare Ni1-xZnxMoO4 (0 ≤ x ≤ 1) nanoflake electrodes to increase the energy density and improve the cycling stability for a wider range of applications of aqueous rechargeable nickel-zinc (NiZn) batteries. This was achieved using a facile hydrothermal method followed by thermal annealing, which can be easily scaled up for mass production. Owing to the unique nanoflake structures, improved conductivity, and tunable electronic interaction, excellent electrochemical performance with high specific capacitance and reliable cycling stability can be achieved. When the Zn doping is 25%, the Ni0.75Zn0.25MoO4 nanoflake electrode displays a high specific capacitance of 345.84 mA h g-1 (2490 F g-1) at a current density of 1 A g-1 and improved cycling stability at a high current density of 10 A g-1. NiZn cells assembled with Ni0.75Zn0.25MoO4 nanoflake electrodes and zinc electrodes have a maximum specific capacity of 344.7 mA h g-1 and an energy density of 942.53 W h kg-1. This design strategy for nickel-based electrode materials enables high-performance energy storage and opens up more possibilities for other battery systems in the future.

Green synthesis of emerging ZnO and Ca-doped ZnO nanoparticles towards optical, magnetic properties and its antibacterial application

A green synthesis method is adopted to prepare emerging low cost ZnO (ZNP) and Ca substitute ZnO nanoparticles (CZNP) using Psidium guajava fruit (PGF) extract as an effective reducing and capping agent. An X-ray diffraction study of the synthesized nanoparticles revealed that they have a hexagonal wurtzite structure. The elemental compositions and oxidation states of ZNP and CZNP surfaces are quantified. The HRSEM image shows the nano-flake like structure of the synthesized nanomaterials ZNP and CZNP samples. The elemental compositions were identified using EDAX spectra. From the Raman spectra, the low wavenumber region of 2nd order Raman modes at 341 and 346 cm-1 were ascribed to the difference E2 high-E2 low. Kubelka–Munk (K–M) method is used for estimating direct band gap and it is 3.3 eV and 3.04 eV for ZNP and CZNP respectively. Due to the zinc and oxygen vacancies, six different bands were observed in the photoluminescence spectra. The TG analysis was observed 5.6% of weight loss for ZNP and 5.8% of weight loss for CZNP sample. The Magnetization–Field (M–H) hysteresis curves revealed the appearance of diamagnetic behavior at room temperature. The asfabricated pure ZnO and Ca-doped ZnO nanoparticles were evaluated for the antibacterial activity. The Ca substituted ZnO sample showed higher antibacterial activity than pure ZnO sample.

Composite poly(ethylene oxide)-based solid electrolyte with consecutive and fast ion transport channels constructed by upper-dimensional MIL-53(Al) nanofibers

Novel structural designs for metal organic frameworks (MOFs) are expected to improve ion-transport behavior in composite solid electrolytes. Herein, upper-dimensional MIL-53(Al) nanofibers (MNFs, MIL-53 belongs to the MIL (Material Institute Lavoisier) group) with flower-like nanoflake structures have been designed and constructed via modified hydrothermal coordination. The optimized MNFs with high surface area and porosity can form abundant interfaces with poly(ethylene oxide) (PEO) matrix. The plasticization of MNFs to the PEO matrix will facilitate segmental movement of PEO chains to facilitate Li+ conduction. The unsaturated open metal centers of MNFs can effectively capture bis(trifluoromethanesulfonyl)imide anions (TFSI−) to deliver more free lithium ions for transfer. Moreover, the upper-dimensional nanofiber structure endows lithium ions with a long-range and consecutive transport pathway. The obtained composite solid electrolyte (MNFs@PEO) presents a high ionic conductivity of 4.1 × 10−4 S cm−1 and a great Li+ transference number of 0.4 at 60 °C. The electrolyte also exhibits a stable Li plating/stripping behavior over 1000 h at 0.1 mA cm−1 with inhibited Li dendrite growth. Furthermore, the Li/LiFePO4 and Li/LiNi0.8Mn0.1Co0.1O2 batteries with MNFs@PEO as electrolytes both display great cycling stabilities with high-capacity retention, indicating their potential applications in lithium metal batteries. The study will put forward new inspirations for designing advanced MOF-based composite solid electrolytes.

Multifaceted applications of chitosan-L-ornithine modified ZnO nanoparticles: Antibacterial, antioxidant, and anticancer potentials

Developing polymeric inorganic nanoparticle-based nanomedicines has significantly advanced antibacterial and anticancer treatments. These innovative agents have attracted significant attention due to their unique physicochemical properties and promising efficacy in targeting bacteria and cancer cells. The primary objective of this study is to investigate the synthesis of chitosan and l-ornithine-supported zinc oxide nanoparticles (ZnCsLO NPs) to assess their biological effects. The X-ray diffraction (XRD) pattern confirmed the synthesis of ZnO and ZnCsLO NPs, with wurtzite hexagonal structure. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) showed nano-flake and polygonal structures for ZnO and ZnCsLO NPs, respectively. Fourier transform infrared (FTIR) spectroscopy of ZnO and ZnCsLO NPs revealed characteristic peaks such as ZnO, chitosan, and l-ornithine molecules. The photoluminescence (PL) spectra of ZnO and ZnCsLO NPs displayed green emission peaks at 519 nm and 527 nm respectively, attributed to oxygen vacancies and inherent defects. The antibacterial activity was tested against various Gram-positive and Gram-negative bacterial strains using the well diffusion method. The ZnCsLO NPs exhibited higher antibacterial activity than ZnO NPs. In terms of antioxidant activity, ZnCsLO NPs exhibited the highest scavenging activity compared to ZnO NPs against DPPH. The anticancer activity of ZnO and ZnCsLO NPs was tested against the breast cancer cell line MDA-MB-231, where ZnCsLO NPs exhibited higher anticancer activity than ZnO NPs. Toxicity studies of ZnCsLO NPs on human fibroblast L929 showed less harmful effect on healthy cells compared to ZnO. Based on the findings of this research, there is a strong indication that ZnCsLO NPs hold great potential as a nanomaterial well-suited for advanced biomedical industrial applications.

Enhancing the electrochemical and photovoltaic performance of hexagonal tin disulfide nanoflakes for dye-sensitized solar cells counter electrode by Tantalum dopant

The ongoing effort to stabilize and enhance dye-sensitized solar cells (DSSCs) efficiency has prompted the solar society to adopt innovative strategies. The counter electrode (CE) plays a crucial role, with platinum (Pt) being effective but expensive. Transition metal dichalcogenides (TMDs) like Tin sulphide (SnS2) show promise as alternatives to Pt. In this work, Tantalum (Ta)-doped SnS2 hexagonal nanoflakes have been synthesized by the hydrothermal method. Characterization using X-ray diffraction (XRD), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS) revealed the impact of dopants on these nanoflakes. XRD, Raman, and HRTEM confirmed the hexagonal structure of nanoflakes. Electrochemical impedance spectroscopy (EIS) indicated a reduced charge transfer resistance (Rct) value of 1.51 Ω. Cyclic voltammetry (CV) analyses confirmed the improved electrocatalytic activity and superior redox reaction. Therefore, Ta dopant SnS2-based CE offers cost-effective and enhanced power conversion efficiency (PCE) in DSSC.

Nickel oxide doping impact on the NO2 sensing properties of nanostructured zinc oxide deposited by spray pyrolysis

In this study, zinc oxide was doped with varying Nickel oxide nanostructured thin film concentrations using spray pyrolysis at 400 °C. At low Ni content, the ZnO phase exhibited polycrystalline structures, whereas a high Ni concentration resulted in the development of an additional NiO phase. The morphological analysis indicates the presence of nano-spherical structures at lower Ni concentrations, with nanoflakes embedded at varying orientations. The density of the nanoflakes structure was observed to increase as the Ni content was increased, enhancing the surface-to-volume ratio, which has potential applications in gas sensing. The highest sensitivity was detected for the sample doped with the highest Ni content, which can be attributed to its superior effective surface area. The optimal sensitivity was 45.26% at 200 °C.