Search

This paper reports the rapid synthesis, characterization, and photovoltaic and sensing applications of TiO2 nanoflowers prepared by a facile low-temperature solution process. The morphological characterizations clearly reveal the high-density growth of a three-dimensional flower-shaped structure composed of small petal-like rods. The detailed properties confirmed that the synthesized nanoflowers exhibited high crystallinity with anatase phase and possessed an energy bandgap of 3.2 eV. The synthesized TiO2 nanoflowers were utilized as photo-anode and electron-mediating materials to fabricate dye-sensitized solar cell (DSSC) and liquid nitroaniline sensor applications. The fabricated DSSC demonstrated a moderate conversion efficiency of ~3.64% with a maximum incident photon to current efficiency (IPCE) of ~41% at 540 nm. The fabricated liquid nitroaniline sensor demonstrated a good sensitivity of ~268.9 μA mM−1 cm−2 with a low detection limit of 1.05 mM in a short response time of 10 s.

Fluoropolymers play an essential role in electrowetting (EW) systems. However, no fluoropolymer possesses the desirable properties of both hydrophobicity and dielectric strength. In this study, for the first time, we report the integration of two representative fluoropolymers—namely, Teflon AF (AF 1600X) and Cytop (Cytop 809A)—into one bifunctionalized dielectric nanolayer. Within this nanolayer, both the superior hydrophobicity of Teflon AF and the excellent dielectric strength of Cytop were able to be retained. Each composed of a 0.5 μm Cytop bottom layer and a 0.06 μm Teflon AF top layer, the fabricated composite nanolayers showed a high withstand voltage of ~70 V (a dielectric strength of 125 V/μm) and a high water contact angle of ~120°. The electrowetting and dielectric properties of various film thicknesses were also systemically investigated. Through detailed study, it was observed that the thicker Teflon AF top layers produced no obvious enhancement of the Cytop/Teflon AF stack.

Herein, MoS2-ZnO heterostructure nanorods were hydrothermally synthesized and characterized in detail using several compositional, optical, and morphological techniques. The comprehensive characterizations show that the synthesized MoS2/ZnO heterostructure nanorods were composed of wurtzite hexagonal phase of ZnO and rhombohedral phase of MoS2. The synthesized MoS2/ZnO heterostructure nanorods were used as a potent photocatalyst for the decomposition of methylene blue (MB) dye under natural sunlight. The prepared MoS2/ZnO heterostructure nanorods exhibited ~97% removal of MB in the reaction time of 20 min with the catalyst amount of 0.15 g/L. The kinetic study revealed that the photocatalytic removal of MB was found to be in accordance with pseudo first-order reaction kinetics with an obtained rate constant of 0.16262 min−1. The tremendous photocatalytic performance of MoS2-ZnO heterostructure nanorods could be accredited to an effective charge transportation and inhibition in the recombination of photo-excited charge carriers at an interfacial heterojunction. The contribution of active species towards the decomposition of MB using MoS2-ZnO heterostructure nanorods was confirmed from scavenger study and terephthalic acid fluorescence technique.

Antibacterial materials are of great importance in preventing bacterial adhesion and reproduction in daily life. Silver nanoparticle (AgNP) is a broad-spectrum antibacterial nanomaterial that has attracted significant attentions for its ability to endow natural materials with antibacterial ability. Silk sericin (SS) has a great advantage for biomaterial application, as it is a natural protein with excellent hydrophilicity and biodegradability. In this study, we prepared AgNPs and polyelectrolyte membrane (PEM) modified SS/Agar films through the layer-by-layer adsorption technique and ultraviolet-assisted AgNPs synthesis method. The film was well characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy. Other properties such as water contact angle, wettability and tensile strength, the release of silver were also studied. The antimicrobial activity of AgNPs-PEM-SS/Agar film was investigated against Escherichia coli and Staphylococcus aureus as the model microorganisms by the inhibition zone and bacterial growth curve assays. The results suggested that the AgNPs-PEM-SS/Agar film had excellent mechanical performance, high hydrophilicity, prominent water absorption ability, as well as outstanding and durable antibacterial activity. Therefore, the prepared novel AgNPs-PEM-SS/Agar composite film is proposed as a potentially favorable antibacterial biomaterial for biomedical applications.

Recent advancement in nanoscience and nanotechnology has witnessed numerous triumphs of zinc oxide (ZnO) nanomaterials due to their various exotic and multifunctional properties and wide applications. As a remarkable and functional material, ZnO has attracted extensive scientific and technological attention, as it combines different properties such as high specific surface area, biocompatibility, electrochemical activities, chemical and photochemical stability, high-electron communicating features, non-toxicity, ease of syntheses, and so on. Because of its various interesting properties, ZnO nanomaterials have been used for various applications ranging from electronics to optoelectronics, sensing to biomedical and environmental applications. Further, due to the high electrochemical activities and electron communication features, ZnO nanomaterials are considered as excellent candidates for electrochemical sensors. The present review meticulously introduces the current advancements of ZnO nanomaterial-based chemical sensors. Various operational factors such as the effect of size, morphologies, compositions and their respective working mechanisms along with the selectivity, sensitivity, detection limit, stability, etc., are discussed in this article.

In this paper, we systematically investigated the influence of fluoride on the morphology and electrochemical property of Co3O4 nanostructures for hydrazine detection. The results showed that with the introduction of NH4F during the synthesis process of Co3O4, both Co(CO3)0.5(OH)·0.11H2O and Co(OH)F precursors would be generated. To understand the influence of F on the morphology and electrochemical property of Co3O4, three Co3O4 nanostructures that were respectively obtained from bare Co(CO3)0.5(OH)·0.11H2O, Co(OH)F and Co(CO3)0.5(OH)·0.11H2O mixtures and bare Co(OH)F were successfully synthesized. The electrochemical tests revealed the sensing performance of prepared Co3O4 nanostructures decreased with the increase in the fluoride contents of precursors. The more that dosages of NH4F were used, the higher crystallinity and smaller specific surface area of Co3O4 was gained. Among these three Co3O4 nanostructures, the Co3O4 that was obtained from bare Co(CO3)0.5(OH)·0.11H2O-based hydrazine sensor displayed the best performances, which exhibited a great sensitivity (32.42 μA·mM−1), a low detection limit (9.7 μΜ), and a wide linear range (0.010–2.380 mM), together with good selectivity, great reproducibility and longtime stability. To the best of our knowledge, it was revealed for the first time that the sensing performance of prepared Co3O4 nanostructures decreased with the increase in fluoride contents of precursors.

Herein, we report the growth of In-doped ZnO (IZO) nanomaterials, i.e., stepped hexagonal nanorods and nanodisks by the thermal evaporation process using metallic zinc and indium powders in the presence of oxygen. The as-grown IZO nanomaterials were investigated by several techniques in order to examine their morphological, structural, compositional and optical properties. The detailed investigations confirmed that the grown nanomaterials, i.e., nanorods and nanodisks possess well-crystallinity with wurtzite hexagonal phase and grown in high density. The room-temperature PL spectra exhibited a suppressed UV emissions with strong green emissions for both In-doped ZnO nanomaterials, i.e., nanorods and nanodisks. From an application point of view, the grown IZO nanomaterials were used as a potential scaffold to fabricate sensitive phenyl hydrazine chemical sensors based on the I–V technique. The observed sensitivities of the fabricated sensors based on IZO nanorods and nanodisks were 70.43 μA·mM−1·cm−2 and 130.18 μA·mM−1·cm−2, respectively. For both the fabricated sensors, the experimental detection limit was 0.5 μM, while the linear range was 0.5 μM–5.0 mM. The observed results revealed that the simply grown IZO nanomaterials could efficiently be used to fabricate highly sensitive chemical sensors.

Highly sensitive acetone chemical sensor was fabricated using ZnO nanoballs modified silver electrode. A low temperature, facile, template-free hydrothermal technique was adopted to synthesize the ZnO nanoballs with an average diameter of 80 ± 10 nm. The XRD and UV-Vis. studies confirmed the excellent crystallinity and optical properties of the synthesized ZnO nanoballs. The electrochemical sensing performance of the ZnO nanoballs modified AgE towards the detection of acetone was executed by simple current–voltage (I–V) characteristics. The sensitivity value of ∼472.33 μA·mM−1·cm−2 and linear dynamic range (LDR) of 0.5 mM–3.0 mM with a correlation coefficient (R2) of 0.97064 were obtained from the calibration graph. Experimental limit of detection (LOD) for ZnO nanoballs modified AgE was found to be 0.5 mM.

Herein, we report a facile synthesis, characterization, and electrochemical sensing application of ZnO nanopeanuts synthesized by a simple aqueous solution process and characterized by various techniques in order to confirm the compositional, morphological, structural, crystalline phase, and optical properties of the synthesized material. The detailed characterizations revealed that the synthesized material possesses a peanut-shaped morphology, dense growth, and a wurtzite hexagonal phase along with good crystal and optical properties. Further, to ascertain the useful properties of the synthesized ZnO nanopeanut as an excellent electron mediator, electrochemical sensors were fabricated based on the form of a screen printed electrode (SPE). Electrochemical and current-voltage characteristics were studied for the determination of picric acid sensing characteristics. The electrochemical sensor fabricated based on the SPE technique exhibited a reproducible and reliable sensitivity of ~1.2 μA/mM (9.23 μA·mM−1·cm−2), a lower limit of detection at 7.8 µM, a regression coefficient (R2) of 0.94, and good linearity over the 0.0078 mM to 10.0 mM concentration range. In addition, the sensor response was also tested using simple I-V techniques, wherein a sensitivity of 493.64 μA·mM−1·cm−2, an experimental Limit of detection (LOD) of 0.125 mM, and a linear dynamic range (LDR) of 1.0 mM–5.0 mM were observed for the fabricated picric acid sensor.