Journal of Nanoanalysis
Volume:9 Issue: 2, Apr 2022

In this paper, a new Nano-Scale structure of dual material gate oxide stack-double gate TFET (DMGOS-DG TFET) with the inclusion of the dielectric pocket (DP) in the drain region is proposed. Hence the gate consists of three parts, named M1, M2, and M3 with work functions ϕM1, ϕM2, and ϕM3 respectively. The work function engineering with the gate oxide stack (SiO2 as the bottom layer and HfO2 as the top layer) improves ON current, leakage current, and ambipolar behavior. In addition, the dielectric pocket (DP) has been used in the drain region to achieve better ambipolar performance. Moreover, it is found that in comparison with the low-k DP (SiO2), the presence of the high-k DP (HfO2) provides a lower ambipolar current due to the greater depletion width in the drain region. Furthermore, the ambipolar behavior of the DP-DMGOS-DG TFET structure has been investigated by changing the length and thickness of the high-k DP. Finally, the comparative analysis of DMGOS-DGTFET and high-k DP-DMGOS-DG TFET on high-frequency performance reveals that DP inclusion reduces the gate-to-drain capacitance, which leads to the improved cut-off frequency.

In this work, novel Bi14W2O27/Bi2WO6 nanocomposite was prepared by a modified Pechini sol-gel approach. The effect of the gelling agent, chelating agent and mole ratio of chelating agent to total metals was controlled to produce ultrafine Bi14W2O27/Bi2WO6 nanoparticles. The as-prepared Bi14W2O27/Bi2WO6 nanocomposite was characterized by XRD, FESEM, FT-IR, EDS and UV–Vis analysis. The Bi14W2O27/Bi2WO6 nanostructures exhibited excellent photocatalytic desulfurization of thiophene (~90%) after 120 min of simulated sunlight irradiation. The high-efficiency photocatalytic desulfurization of the as-prepared Bi14W2O27/Bi2WO6 can be attributed to the improved visible-light absorption, ultrafine nanoparticles, and high separation and low recombination rates of charge carriers. In addition, a reliable photocatalytic desulfurization mechanism was explained using radical trapping experiment, which indicated that the photogenerated •O2− and •OH species had a significant contribution in the photocatalytic desulfurization reactions of Bi14W2O27/Bi2WO6 nanocomposite. The excellent photocatalytic desulfurization efficiency, good recyclability, solar-driven, and simple synthesis of Bi14W2O27/Bi2WO6 nanocomposite are promising for photocatalytic applications.

In this study, through the application of TiO2/ZnS as a novel nano photocatalyst, the degradation of AR18 in synthetic wastewater was explored. The nano photocatalyst was synthesized by the co-precipitation method and characterized by Scanning electron microscopy (SEM), Fourier transfer infrared (FTIR), and X-ray powder diffraction (XRD) techniques. The average size of ZnS/TiO2 nano photocatalyst was 79nm. For experimental design and statistical analysis of each factor including AR18 concentration, pH, catalyst dosage, and treatment time on the degradation rate of AR18 (response) by Central Composite Design (CCD) was used. The analysis of variance (ANOVA) demonstrates a second-order regression model with R2 = 0.9995, adjusted R2=0.9991, and predicted R2=0.9982) for the removal of AR18. The optimum conditions for each operating factor were as the following: AR18 concentration at 30 mg.L-1, catalyst dosage at 1.2 g.L-1, pH at 5, and treatment time at 120 min. In this condition, the actual and predicted AR18 removal was 94% and, 93.07%, respectively.

In this study, TiO2/Ag nano photocatalyst was synthesized by sol-gel method and used for degradation of Chloridazon (CLZ) in aqueous media. The prepared catalyst was characterized using powder X-ray diffractometry (XRD), Fourier transform infra-red (FTIR), and field emission scanning electron microscopy (FESEM) techniques. The Crystallite size of pure TiO2 and Ag/TiO2 nanoparticles was 20 and 60 nm, respectively. The Central Composite Design (CCD) was employed for experimental design and statistical analysis of independent operational parameters. According to the results of Response Surface Methodology (RSM) plots of Design-Expert software, the optimal conditions for each critical variable were as the follows: time at 113 min, pH at 6.8, initial concentration of CLZ at 40 mg/l, and catalyst concentration at 0.83gr/l. The maximum effectiveness in the experimental and predicted CLZ removal was 94.2 and 93.5%, respectively. The outcomes of Analysis of variance (ANOVA) demonstrated high determination coefficient quantities (R2 = 0.9997, Predicted R2=0.9989, and Adjusted R2=0.9994) which validated the reliability of the second-order regression model.

Three-dimensional mesoporous CeO2 hollow sphere (M-CeO2-HS) modified glassy carbon electrode (M-CeO2-HS/GCE) was developed in this study as a very sensitive voltammetric sensor for detection of terazosin. This produced modifier was characterized by techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). There was a remarkable improvement in the electrochemical behavior relative to terazosin electro-oxidation on M-CeO2-HS/GCE surface, compared to bare GCE, in the optimized conditions of supporting electrolyte pH and casted modifier concentration. An oxidation peak was found for terazosin on modified electrode surface at the potential of about 0.57 V in phosphate buffer solution (pH=7.0). The linear dynamic range was 0.01 to 600.0 µM and the limit of detection was 1.9 nM with the aid of anodic peak of terazosin. Some advantages were reported for the modified electrode, including satisfactory reproducibility towards terazosin, potent stability, strong sensitivity and easy production. Practical applicability of the M-CeO2-HS/GCE was tested to detect the low level of terazosin in clinical and pharmaceutical formulations.

The wastewater containing Tert- Butyl alcohol (TBA) contains water-soluble polymer discharged from different chemical and textile industries. In this study, through the application of the UV/ZnFe2O4 approach in a batch photoreactor, the decomposition of synthetic wastewater including TBA was investigated. The co-precipitation method was utilized for synthesizing the ZnFe2O4 nano photocatalyst. Using FTIR spectroscopy, XRD, and SEM images, the characterization of catalyst was ascertained. For evaluation and exploration of the stability of nano photocatalyst particles, the Zeta potential was utilized. The influence of different crucial factors including the concentration of catalyst, the initial dosage of contaminants, and pH, on the mineralization of TBA was studied. At optimal situations (pH at 6, 25 mg/l of TBA, and 0.9 g/l of catalyst) and after 120 min of remediation time, around 58% of Chemical Oxygen Demand (COD) and 93.5% of TBA was eliminated. The main reason for the generation of active radicals in the photocatalytic method is the electron-hole mechanism. According to the Langmuir Hinshelwood model, the kinetic of the TBA decomposition was elucidated hence, the half-life of the reaction and the apparent rate of the pseudo-first-order reaction, (t_(1/2)=35 min) and (K_app=1.98×10^(-2) min^(-1)) was obtained, respectively.

In this paper, we report a new method for the synthesis of spherical CoO nanoparticles using a new metal-organic framework of Co(II). Nano particles of a coordination polymer compound, [Co(3,5-DNBA)]n (1) (L- = 3,5-dinitro benzoic acid) was synthesized and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and IR spectroscopy. The thermal stability of compound 1 has been studied by thermal gravimetric (TG) and differential thermal analyses (DTA), and UV-vis spectroscopy. In addition, compound 1 was used as a precursor for the synthesis of Cobalt oxide nano-particles. Two pathways, the first sonochemical process, and the second, hydrothermal method were used for preparing the mentioned nano-particles. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and IR spectroscopy were used to characterize the CoO nano-structures. Experimental results showed that the morphology of the CoO nanoparticles is spherical and the size of the nanoparticles is dependent on the particle size of compound 1.

It has been found that semiconductor nanocomposites have good photocatalytic behavior and can be used for the photodegradation of organic pollutants in water waste. ZnO, one of the eco-friendly semiconductor materials, was chosen to form a nanocomposite with graphene oxide. Graphene oxide in ZnO-based nanocomposites improves the photoactivity and photostability of ZnO. To prepare the graphene oxide, the Hummers method was used, then ZnO/GO nanocomposite was synthesized by hydrothermal method. The nanocomposites were annealed at different temperatures of 300 °C, 400 °C, and 500 °C. Raman spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR) confirmed the structure of synthesized graphene oxide nanosheets. Structural characterization of the nanocomposites was investigated using X-ray diffraction, Transmission Electron Microscope (TEM), and Field Emission Scanning Electron Microscope (FE-SEM). X-ray diffraction patterns of nanocomposites demonstrate that the annealed sample at 300 °C has better crystallinity than the other samples and was used to investigate the photocatalytic process. Photocatalytic experiment of the ZnO/GO was carried out by degradation of methylene blue using a laboratory-made reactor in alkaline, acidic, and neutral solutions. Photodegradation results were revealed that the maximum percent degradation of 87% was achieved in the alkaline solution.