Tuning of energy gap, microstructure, optical and structural properties of Cr doped Zn0.96Cu0.04O nanoparticles

Estimating the in vitro cytotoxicity of the newly emerged zinc oxide (ZnO) doped chromium nanoparticles using the human fetal lung fibroblast cells (WI38 cells)

Advances in nanotechnology have been increased for more smart applications and getting the highest level of benefits, recently modification of the surface characters of nanoparticles is a new trend to get the optimal benefits, one of these modification is doping of zinc oxide with chromium nanoparticles (ZnO doped Cr NPs), the present study aimed to identify the surface characters of doped ZnO and their possible cytotoxic effects. The doped NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field emission scanning electron microscope (FESEM), and Electromagnetic Data Exchange (EDX). Human fetal lung fibroblast cells (WI38 Cells) was treated with variable concentrations of pure ZnO and ZnO doped Cr (0.01 %, 0.02 %, 0.03 % and 0.04 %) for 24 hr at 37 °C followed by the MTT assay. The cells treated with the obtained half-maximal inhibitory concentration (IC50). The supernatant and cells were collected for oxidant/anti-oxidant and molecular analysis.The observed FESEM features are in line with the reported XRD analysis confirming the hexagonal crystal symmetry of all samples. The findings revealed that pure ZnO exhibited potent cytotoxic effects followed by (0.03 % and 0.04 %). All tested NPs produce lipid peroxidation significantly (0.03 % and 0.04 %). The significant up regulation of Bcl-2-associated X protein (BAX) and apoptotic Caspase (Cas-3) transcription level were reported in ZnO and 0.03 % and 0.04 % in contrast the anti apoptitic B-cell lymphoma 2 (Bcl-2) is elevated in 0.01 % and 0.02 %. Doping of ZnO with Cr causing significant morphological changes which effect on their toxicity especially with 0.03 % and 0.04 %.

Alzahrani K, Althomali RH, Althobaiti SA. Electrochemical Detection of 4-Nitrophenol Using a Novel SrTiO3/Ag/rGO Composite

In this study, an eco-friendly strategy was used to prepare a novel SrTiO3/Ag/rGO composite. A SrTiO3/Ag/rGO composite-modified screen-printed carbon electrode (SPCE) was applied for the electrochemical detection of 4-nitrophenol. A simple ultrasonic method with an ultrasonic frequency of 20 kHz was used for the synthesis of SrTiO3/Ag/rGO composite material. The obtained SrTiO3/Ag/rGO composite was characterized by X-ray diffraction, Fourier transform infrared, Raman spectroscopy, field emission electron microscopy, and UV-visible spectroscopy. Electrochemical impedance spectroscopy was used to determine the electrical conductivity of the SrTiO3/Ag/rGO composite. The electrochemical properties of the modified electrode were studied using cyclic voltammetry as well as linear sweep voltammetry techniques. In comparison to SrTiO3/SPCE, SrTiO3/Ag/SPCE, and SrTiO3/rGO/SPCE electrodes, SrTiO3/Ag/rGO/SPCE demonstrates a considerable increase in 4-nitrophenol redox peak current. At optimum conditions, a large linear response range of 0.1-1000 M, with a relatively low limit of detection (0.03 M), outperforms the previously published modified electrode for 4-nitrophenol. Moreover, the SrTiO3/Ag/rGO/SPCE electrode-based 4-nitrophenol sensor is distinguished by good selectivity, high stability, and repeatability. Furthermore, SrTiO3/Ag/rGO/SPCE contributed to the detection of 4-nitrophenol in river water and drinking water with the recovery range from 97.5 to 98.7%. The experimental finding was supported by density functional theory calculation.

SILAR-Deposited CuO Nanostructured Films Doped with Zinc and Sodium for Improved CO2 Gas Detection

Gas sensing is of significant importance in a wide range of disciplines, including industrial safety and environmental monitoring. In this work, a low-cost SILAR (Successive Ionic Layer Adsorption and Reaction) technique was employed to fabricate pure CuO, Zn-doped CuO, and Na-doped CuO nanotextured films to efficiently detect CO2 gas. The structures, morphologies, chemical composition, and optical properties of all films are characterized using different tools. All films exhibit a crystalline monoclinic phase (tenorite) structure. The average crystallite size of pure CuO was 83.5 nm, whereas the values for CuO/Zn and CuO/Na were 73.15 nm and 63.08 nm, respectively. Subsequently, the gas-sensing capabilities of these films were evaluated for the detection of CO2 in terms of sensor response, selectivity, recovery time, response time, and limits of detection and quantification. The CuO/Na film offered the most pronounced sensitivity towards CO2 gas, as evidenced by a sensor response of 12.8% at room temperature and a low limit of detection (LoD) of 2.36 SCCM. The response of this sensor increased to 64.5% as the operating temperature increased to 150 °C. This study thus revealed a brand-new CuO/Na nanostructured film as a highly effective and economically viable sensor for the detection of CO2.

Influence of Zirconium (Zr4+) Substitution on the Crystal Structure and Optical and Dielectric Properties of Sr0.8Mg0.2(Sn1-xZrx)O3 Ceramics

In this work, new compositions of Sr0.8Mg0.2(Sn1-xZrx)O3 0.00 ≤ x ≤ 0.06 ceramics are designed and synthesized by the conventional solid-state route. The influence of Zr doping on the phase, microstructural, optical, and dielectric properties is thoroughly investigated. The peaks (0 0 4) and (1 1 0) are observed to shift toward lower 2θ values, due to the variation of the ionic radius between Zr4+ and Sn4+. X-ray diffraction patterns reveal the orthorhombic structure with the space group Pbnm. Scanning electron microscopy images reveal the presence of pores and particles with a high degree of agglomeration. The functional groups and modes of vibration are determined by Fourier transform infrared spectroscopy of the prepared metal oxide samples. The existence of green emission of all the synthesized samples around 554.91 nm is identified by photoluminescence spectroscopy. The dielectric properties of the fabricated samples are measured by using an impedance analyzer. The values of the tangent loss and relative permittivity are found to decrease with increasing frequency.