Nanocomposite NiO Research Articles

Van-mediated self-aggregating photothermal agents combined with multifunctional magnetic nickel oxide nanoparticles for precise elimination of bacterial infections

Building a novel and efficient photothermal antibacterial nanoplatform is a promising strategy for precise bacterial elimination. Herein, a nanocomposite NiO NPs@AuNPs@Van (NAV) for selective MRSA removal was constructed by electrostatic self-assembly of highly photothermal magnetic NiO NPs and vancomycin (Van)-modified gold nanoparticles (AuNPs). In the presence of MRSA and under NIR irradiation, Van-mediated AuNPs can self-aggregate on MRSA surface, generating photothermal effect in situ and killing 99.6% MRSA in conjunction with magnetic NiO NPs. Additionally, the photothermal efficiency can be improved by magnetic enrichment due to the excellent magnetism of NAV, thereby enhancing the bactericidal effect at a lower experimental dose. In vitro antibacterial experiments and full-thickness skin wound healing test demonstrated that this combination therapy could effectively accelerate wound healing in MRSA-infected mice, increase collagen coverage, reduce IL-6 and TNF-α content, and upregulate VEGF expression. Biological safety experiments confirmed that NAV has good biocompatibility in vivo and in vitro. Overall, this work reveals a new type of nanocomposite with enhanced photothermal antibacterial activity as a potential nano-antibacterial agent for treating bacteria-infected wounds.

Preparation and Properties of Boron‐Based Nano‐B/NiO Thermite

AbstractBoron particles have several major burning problems, such as incomplete combustion, poor ignitability, and a complex burning process in solid propellants. It is documented that the low ignitability and combustion efficiency of boron are caused by the oxidation of its surface. In order to improve the combustion efficiency of boron particles, a precipitation method was employed to prepare nanometer‐sized NiO and coat it on boron particles. The morphology and coating results of the B/NiO nanocomposite thermite were characterized using different approaches such as SEM, X‐ray Diffraction (XRD), and EDS. The results indicated that the boron particles were well distributed and coated completely by nanocomposite NiO. The B/NiO nanocomposite thermite reaction process was tested by TG‐DTA. The results showed that the reaction temperature of B/NiO particles is about 30 °C lower than that of boron particles. The B/NiO thermite and boron powder were added to Mg/PTFE propellant to be measured for their respective combustion performance. The results showed that the burning rate of the B/NiO‐Mg/PTFE propellant increased by 22.8–25.2 %, mass burning rate by 26.7–30.8 %, and combustion temperature increased by 8–56 °C compared to the B‐Mg/PTFE propellant. The above results indicate that NiO coating of boron particles has a significant effect on the combustion behavior and increases the combustion performance of the propellant compared with uncoated particles.

Nanocomposite NiO:Pd hydrogen sensors with sub-ppm detection limit and low operating temperature

We present results on the fabrication of chemiresistive nanocomposite NiO:Pd hydrogen sensors, which are able to detect hydrogen concentrations as low as 300ppb in air, operating at temperatures in the 115–145°C range. Thin NiO films were deposited by radio frequency magnetron sputtering on silicon and quartz substrates and their structural and morphological properties were characterised. Pd nanoparticles were added on the NiO surface via pulsed laser deposition and the films were tested as hydrogen sensors before and after Pd deposition. The presence of Pd nanoparticles improved the sensor performance, leading to the detection of hydrogen concentrations at sub-ppm levels. Moreover, the response time of the sensors decreased by a factor between two and four.

Nanocomposite NiO:Au hydrogen sensors with high sensitivity and low operating temperature

We present results on the development of nanocomposite NiO:Au thin-film hydrogen sensors, which are able to detect hydrogen concentrations as low as 2ppm in air, operating at low temperatures in the range 125–150°C. Thin NiO films were sputter-deposited on oxidized silicon substrates. The structural, morphological, and nanomechanical properties of the films were investigated with respect to post-deposition annealing. Au nanoparticles were added on the NiO surface via pulsed laser deposition and the films were tested as hydrogen sensors before and after Au deposition. The performance of the NiO films as hydrogen sensors improved significantly in the presence of Au nanoparticles on the surface. The detection limit (lowest detectable hydrogen concentration) decreased by two orders of magnitude, while the response time also decreased by a factor of three.

The potential and challenges of thin-film electrolyte and nanostructured electrode for yttria-stabilized zirconia-base anode-supported solid oxide fuel cells

Thin-film electrolytes and nanostructured electrodes are essential components for lowering the operation temperature of solid oxide fuel cells (SOFCs); however, reliably implementing thin-film electrolytes and nano-structure electrodes over a realistic SOFC platform, such as a porous anode-support, has been extremely difficult. If these components can be created reliably and reproducibly on porous substrates as anode supports, a more precise assessment of their impact on realistic SOFCs would be possible. In this work, structurally sound thin-film and nano-structured SOFC components consisting of a nano-composite NiO–yttria-stabilized zirconia (YSZ) anode interlayer, a thin YSZ and gadolinia-doped ceria (GDC) bi-layer electrolyte, and a nano-structure lanthanum strontium cobaltite (LSC)-base cathode, are sequentially fabricated on a porous NiO–YSZ anode support using thin-film technology. Using an optimized cell testing setup makes possible a more exact investigation of the potential and challenges of thin-film electrolyte and nanostructured electrode-based anode-supported SOFCs. Peak power densities obtained at 500 °C surpass 500 mW cm−2, which is an unprecedented low-temperature performance for the YSZ-based anode-supported SOFC. It is found that this critical, low-temperature performance for the anode-supported SOFC depends more on the electrode performance than the resistance of the thin-film electrolyte during lower temperature operation.

Improved coulombic efficiency in nanocomposite thin film based on electrodeposited-oxidized FeNi-electrodes for lithium-ion batteries

Electrochemical deposition from Ni2+ and Fe2+ using sulfate and nitrate solutions is carried out under galvanostatic regime. The resulting films are oxidized and examined in lithium test cells as potential anode materials for lithium-ion batteries. X-ray diffraction, XPS and SAED–TEM analyses revealed a thin film based on nanocomposite NiO and Fe2O3. Cycling studies show the smallest discharge polarization ever reported during the conversion reactions of metal oxides at ∼0.8V. Unlike typical transition metal oxides, the amorphous oxidized material exhibited low irreversibility from first to second discharge (∼15%) and a distinctive plateau on consecutive discharge branches. The changes in the film thickness on increasing deposition time and the crystallization phenomena on annealing the deposits strongly affect the electrochemical behavior. The present approach allows preparing a powder free electrode with improved coulombic efficiency directly on the current collector and opens a set of novel preparation routes in this field with intriguing results.

Optimized hydrogen sensing properties of nanocomposite NiO:Au thin films grown by dual pulsed laser deposition

Nanocomposite NiO:Au thin films, formed by gold nanoparticles embedded in a nickel oxide matrix, have been grown by reactive pulsed laser deposition (R-PLD). Two actively synchronized nanosecond laser sources, a KrF excimer laser (248 nm) and a Nd:YAG laser (355 nm), were used for the simultaneous ablation of nickel and gold targets in oxygen ambient. The morphology, composition, and optical properties of the obtained nanocomposites were investigated and were found to correlate with the concentration of Au nanoparticles. Further, the NiO:Au nanocomposites have been tested as hydrogen sensors. Embedding Au nanoparticles into the NiO film matrix reduced the sensors operating temperature and improved their performance by orders of magnitude.

Properties of pulsed laser deposited nanocomposite NiO:Au thin films for gas sensing applications

Nanocomposite thin films formed by gold nanoparticles embedded in a nickel oxide matrix have been synthesized by a new variation of the pulsed laser deposition technique. Two actively synchronized laser sources, a KrF excimer laser at 248 nm and an Nd:YAG laser at 355 nm, were used for the simultaneous ablation of nickel and gold targets in oxygen ambient. The structural, morphological, and electrical properties of the obtained nanocomposite films were investigated in relation to the fluence of the laser irradiating the gold target. The nanocomposite thin films were tested as electrochemical hydrogen sensors. It was found that the addition of the gold nanoparticles increased the sensor sensitivity significantly.

Optical Sensing of CO with Nanocomposite NiO and NiO/Au in Porous Silica Thin Films

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