- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effect of Annealing on the Surface Morphology, Optical and and Structural Properties of Nanodimensional Tungsten Oxide Prepared by Coprecipitation Technique
摘要： Tungsten oxide (WO3) nanoparticles with monoclinic structure have been synthesized by using an inexpensive coprecipitation process. The obtained nanoparticles were annealed at 400°C, 500°C, 600°C, 700°C, 800°C, and 900°C for 1 h under the same physical conditions. The morphology, structure, and optical properties of the synthesized nanoparticles were studied by x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet–visible (UV–Vis) spectrophotometry, and Raman spectroscopy. The XRD results confirmed that the synthesized nanomaterial was crystalline in nature with monoclinic phase. The crystallite size varied from 14 nm to 87 nm when changing the annealing temperature. Williamson–Hall analysis was used to investigate the change in lattice strain and crystallite size. The optical performance was investigated by using UV–visible spectroscopy. The bandgap of the prepared nanomaterials varied from 2.51 eV to 3.77 eV with the annealing temperature, due to the variation of the effect of oxygen vacancies on the electronic band structure. SEM revealed formation of uniform and irregular-sized nanoparticles. HRTEM analysis revealed that the nanoparticles grew along the [002] plane with d-spacing of 0.39 nm for the material annealed at 500°C and along the [200] plane with spacing of 0.36 nm when annealed at 800°C. The crystalline nature of the synthesized nanomaterial was confirmed by uniform and clear fringes obtained in TEM micrographs. The correlation between the peak position and width of the key band at 806 cm?1 in Raman spectroscopy band is discussed. These enhancements in the properties of WO3 nanomaterial make it an efficient material for many potential applications, e.g., in photocatalysis, electro- and photochromic devices, etc.
关键词： HRTEM,XRD,SEM,UV–Vis spectroscopy,Raman spectroscopy
更新于2025-09-04 15:30:14
-
A Simple Synthetic Approach To Prepare Silver Elongated Nanostructures: From Nanorods to Nanowires
摘要： A procedure for one-pot preparation and characterization of silver 1D nanostructures is described. The main advantages of this synthetic approach are the simplicity and reproducibility, where the size of the final product can be controlled just by changing the reaction time. This experiment is designed as a laboratory introduction to colloidal chemistry for undergraduate and graduate students; they can appreciate the role of the different reagents in a relatively complex reaction and understand the relation between the morphology of a metal at the nanoscale and some macroscopic properties, such as its visible absorption spectrum (i.e., color).
关键词： Nanotechnology,Synthesis,Second-Year Undergraduate,UV?Vis Spectroscopy,Physical Chemistry,Laboratory Instruction,Hands-On Learning/Manipulatives,First-Year Undergraduate/General,Metals,Colloids
更新于2025-09-04 15:30:14
-
Detection in UV-visible spectrophotometry: Detectors, detection systems, and detection strategies
摘要： A compilation of the new developments in terms of detection, detections systems and detection strategies in Ultraviolet-Visible (UV-Vis) spectrophotometry is presented and discussed. It is shown that this evolution has promoted the use of UV-Vis spectrophotometry as a simple, sensitive, reliable, and low cost technique, that allows the determination of very low concentrations of compounds, and the use of very small amounts of samples. The versatility, and the portability of the developed equipment and strategies, have also contributed for the continuous use of UV-Vis spectrophotometry, over the years. By the examples of its use in diverse fields such as agriculture, food, clinical, pharmaceutical, and environmental is highly expectable that detection in UV-Vis spectrophotometry, continues to evolve and to promote this kind of applications.
关键词： Organic compounds,Quantitative analysis,Detectors,Qualitative analysis,UV-vis spectrophotometry,Detection
更新于2025-09-04 15:30:14
-
Study on the Synthesis of GO-AgNP Mixture Assisted by AgNP Based on UV-Vis, SEM-EDX, XRD, and FTIR
摘要： This study aims to determine the effect of silver nanoparticles (AgNP) towards graphene oxide-silver nanoparticles (GO-AgNP) formation using liquid sonication exfoliation (LSE) method. The synthesis results are characterized using UV-Vis spectroscopy, scanning electron microscope (SEM-EDX), X-ray diffraction (XRD), and Fourier transform infra-red (FTIR) spectroscopy. This research begins by making two type of solutions. The first solution is AgNO3 solution which is being varied in concentration, i.e.: 1 mM, 2 mM, 3 mM, and 4 mM. The second solution is the graphite solution. Via the LSE method, AgNO3 that has been heated into becoming AgNP solution is mixed with the graphite solution. The mixture is subjected to 6 hours of ultrasonication. From this study GO or rGO material has been produced through the assistance of AgNP solution by varying the concentration of the AgNO3 solution. The UV-Vis result for 4 mM concentration shows two absorbance peaks with wavelength values of 265 nm and 416.5 nm. This also leads to a redshift of the GO absorbance peak with a wavelength of 252 nm to 265 nm resulting in reduction of GO (rGO) material. The SEM results of GO-AgNP samples do not show the presence of AgNP granules corresponding to the EDX results showing that the oxygen element has the highest percentage. The XRD results are shown by comparing the diffraction patterns of the GO-AgNP sample and that of GO sample. Furthermore FTIR results indicate the presence of C-H alkanes, C=O bonds, and O-H bonds in the GO-AgNP samples.
关键词： GO,XRD,FTIR,UV-Vis spectroscopy,GO-AgNP,AgNP,SEM-EDX
更新于2025-09-04 15:30:14
-
Process Analytical Technology for Online Monitoring of Organic Reactions by Mass Spectrometry and UV–Vis Spectroscopy
摘要： Process analytical technologies (PATs) are used in the pharmaceutical and other industries to monitor chemical processes in real-time with analytical instrumentation. Each PAT analyzer brings its own advantages and disadvantages to the process, and multiplexing PAT analyzers can be advantageous as they can provide confirmatory measurements and increase the overall confidence of the analysis. In a pedagogical setting, online reaction monitoring enables the instructor to explain the fundamentals of instrumental techniques while highlighting pertinent real-world applications. Here we present a teaching laboratory exercise in which students monitor an amide bond formation reaction by flow UV?vis spectroscopy and by mass spectrometric analysis. The coupling of these two specific instruments allows students to investigate two instruments in one laboratory exercise, to explore the fundamentals behind each, and to contemplate the advantages and disadvantages of these instrumental methods. The coupling of the two instruments was aided by 3D printing which allowed students to explore how rapid prototyping can enable the development of innovative procedures.
关键词： Organic Chemistry,Mass Spectrometry,UV?Vis Spectroscopy,Laboratory Instruction,Instrumental Methods,Hands-On Learning/Manipulatives,Upper-Division Undergraduate,Analytical Chemistry,Reactions
更新于2025-09-04 15:30:14
-
Spectrophotometers for labs: A cost-efficient solution based on smartphones
摘要： In this paper, we introduce a proposal to provide students in labs with an alternative to the traditional visible range spectrophotometers (VIS spectrophotometers), whose acquisition and maintenance entails high costs, based on smartphones. Our solution faced two aspects. On the one hand, the software for the smartphone, able to perform the typical functionalities of the traditional spectrophotometers. On the other hand, the portable peripheral support needed to capture the images to be analyzed in the smartphone. The promising results allow this solution to be applied in Bring Your Own Devices (BYOD) contexts.
关键词： BYOD,VIS spectrophotometer,Apache Cordova,scientific equipment for labs,Beer–Lambert law
更新于2025-09-04 15:30:14