Applied Nanoscience最新文献

Liquefied petroleum gas (LPG) is used as fuel for cooking, heating, and transportation globally. This gas is highly inflammable, poisonous, explosive, and hazardous, and it creates several health issues when inhaled. Thus, its leakage detection is of the utmost importance. There are several sensors used for LPG detection, but they have a high operating temperature; therefore, developing sensors that work at normal temperatures has always been a challenge. This paper describes the synthesis of bismuth (Bi)-doped Praseodymium orthoferrite (PrFeO₃) nanomaterials by the sol–gel self-combustion technique and their application in LPG detection. The synthesized nanomaterials were characterized using powder X-ray diffraction (PXRD), field emission scanning electron microscope (FESEM), Brunauer–Emmett–Teller (BET), ultraviolet–visible spectroscopy (UV–Vis), and Fourier transform infrared spectroscopy (FTIR). PXRD reveals that the synthesized nanomaterial has an orthorhombic structure with the Pbnm space group, and the crystallite size (D) changes from 30 to 41 nm. FESEM was used for the analysis of surface morphology. BET analysis reveals the mesoporous nature of synthesized nanomaterials with a 16.331 to 37.645 m²g⁻¹ specific surface area. UV–Vis spectroscopy affirms the optical energy band gap lying between 2.27 and 1.95 eV. The FTIR study represents the existence of different functional groups and their lattice vibration. Synthesized nanomaterials were explored as an LPG detector working at room temperature for the first time. Different sensing parameters have been evaluated. The gas sensing studies reveal that the response and recovery times are 15.3 and 22.4 s for 0.5 vol% of LPG, and the sensor shows high selectivity towards LPG. This study reveals that the designed sensor is capable of working at room temperature, and the synthesized nanomaterials are promising for LPG sensing.

Capsule-shaped nano silver-based reduced graphene oxide nanocomposites (RGO–Ag) are prepared using “one pot” synthetic protocol. Herein, we have taken tamarind leaf extract for the reduction of Ag⁺ ion which has been used towards the synthesis of RGO–Ag nanocomposites. Different temperature conditions are considered for the optimization of formation of nanoparticles. Scanning electron microscope (SEM) has been used to find out the micrograph of as-synthesized nanocomposites. From SEM image, capsule-shaped nanocomposites can be clearly observed. The as-synthesized nanocomposites display a better response to Hg²⁺(aq) in pH 4.0–10. There is negligible effect of other ions for the recognition of Hg²⁺ (aq) ion and, therefore, as-synthesized nanocomposites can be used for the sensitive and selective recognition of mercury (II) ion in aqueous phase. Since tamarind leaf extract has been used as reducing agent and water is used as solvent, it is a green and eco-friendly process. The recognition limit of Hg²⁺ ion in water sample is found to be 15 nM.

In this study, we have investigated numerous influential factors such as length, diameter, impurity introduction, and vacancy defects on the thermal conductivity of carbon nanotubes (CNTs). These investigations were conducted through molecular dynamics simulations using the large-scale atomic/molecular massively parallel simulator (LAMMPS). It is observed that longer CNTs tend to exhibit heightened thermal conductivity, a consequence of the increased support for phonon vibration modes that facilitate efficient thermal transport. Furthermore, CNTs with larger diameters display superior thermal characteristics owing to reduced phonon scattering effects. The introduction of boron doping reduces CNTs thermal conductivity by approximately 3% with the inclusion of 6% boron atoms, whereas nitrogen doping increases it by a similar margin. These doping effects hold great potential for optimizing the performance of MEMS and NEMS devices. This duality in doping offers a versatile means to fine-tune the thermal conductivity of CNTs, enabling effective heat management in micro/nanodevices. By strategically modulating thermal conductivity, we can optimize the heat transfer properties of CNT-based materials and devices. This optimization is of utmost importance in ensuring efficient heat dissipation and averting thermal-induced issues, such as overheating, performance degradation, or failure. Additionally, this paper explores how vacancy defects impact the thermal conductivity of CNTs. By varying the vacancy concentration from 1 to 6%, a decrease in thermal conductivity of approximately 2% to 4% was observed in both SWCNTs and DWCNTs. These results emphasize the pivotal role of defects in perturbing the efficient phonon transport mechanisms in CNTs and suggest the potential for customizing CNTs with specific defect concentrations to enhance their suitability for thermoelectric devices and thermal insulation materials.

We present a straightforward method for determining the crystalline coherence length (D_c) of ZnO-based systems with long-range order in the scale of tens of nanometers. The proposed equation enables calculating D_c by simply utilizing the intensities of two peaks of a Raman measurement, namely: D_c = A (I_E1(LO)/I_E2^high) + 66.5, where I_E1(LO) and I_E2^high are the intensities of E₁(LO) and E₂^high Raman peaks, respectively, and the coefficient A depends on the laser wavelength used as excitation. Such methodology can be applied to measurements taken with most of the visible lasers available for Raman experiments. Based on the results of photoluminescence analyses, it can be inferred that the relative intensities of these Raman peaks are influenced by both D_c and the exciting laser wavelength, owing to resonance processes that selectively involve phonons out of the Brillouin Zone center. A significant competitive advantage of this method stands out in the fact that Raman spectra are very sensitive even to slight structural modifications that are below the detection limit of conventional characterization techniques, such as X-ray diffraction, and the versatile and easy way of performing in-situ analyses, in addition to the possibility to take measurements with microscopic spatial resolution without the demand for large X-ray sources or synchrotron environments.