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Fabrication and characterization of pure and modified Co3O4 nanocatalyst and their application for photocatalytic degradation of eosine blue dye: a comparative study
摘要： The present work deals with the synthesis of cobalt oxide, and Fe2+- and Ni2+-doped cobalt oxide nanoparticles as a catalyst. The study is investigating the different factors in obtaining cobalt oxide, and Fe2+- and Ni2+-doped cobalt oxide nanoparticles. Photocatalytic degradation studies are carried out for water-soluble eosine blue (EB) dye using cobalt oxide, and Fe2+- and Ni2+-doped cobalt oxide nanoparticles in aqueous solution. Different parameters such as initial dye concentration, dose of catalyst, contact time and pH have been studied to optimize reaction conditions. It is observed that photocatalytic degradation is a more effective and faster mode of removing EB dye by cobalt oxide, and Fe2+- and Ni2+-doped cobalt oxide nanoparticles than work done before. The optimum conditions for the removal of the EB dye are initial concentration 40 mg/L, photocatalyst dose 0.8 g/L, and pH 7.5. The EDS technique gives the elemental composition of synthesised cobalt oxide, and Fe2+- and Ni2+-doped cobalt oxide nanoparticles. The TEM and XRD studies are carried for morphological feature characteristics of synthesized cobalt oxide, and Fe2+- and Ni2+-doped cobalt oxide nanoparticles. Pseudo-first-order kinetic has been investigated for both pure and doped cobalt oxide catalysts. Almost 95% dye degradation has been observed for doped cobalt oxide nanoparticles.
关键词： Photocatalytic degradation,Modified cobalt oxide nanoparticles,Eosine blue,EDS,SEM,XRD,TEM
更新于2025-09-04 15:30:14
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Improve spectroscopic structural and AC electrical conductivity of PC/PEO blend using graphene
摘要： Nanocomposites of polycarbonate (PC) and polyethylene oxide (PEO) embedded with graphene oxide (GO) nanopowder have been prepared using casting method. Prepared nanocomposites are studied and investigated using di?erent characterization techniques. The X-ray di?raction (XRD) pattern reveals the semi-crystalline nature of PC/PEO blend. There are no signi?cant peaks characterizing pure graphene. The intensity of the main X-ray peak characterizing the blend is decreased with the increase of graphene content con?rming a mod- i?cation in the blend due to an addition of graphene oxide. The FT-IR spectra display the main characteristic IR bands due to vibrational function groups for the components. The Optical absorption spectra are measured as a function of wavelength in the range of 190–1100 nm. The UV/V spectra show two absorption bands at 290 and 620 nm due to electronic transitions. The value of Eg is obtained using indirect transition and its decrease with increasing the amount of graphene. The behavior of ε′ and ε″ decreased with the increase of frequencies is observed. After adding graphene, the frequency is increased due to the dipole moment. The decrease of ε″ with increases of both the frequency and the temperature attributed to the origin of ε″ is the conduction losses. The decrease of dissipation factor (tan δ) is ascribed to the internal polarization mechanism related to applied fre- quencies. The maximum value of the peak at M″ relation explained as being the result of the distribution of relaxation time.
关键词： Graphene nanopowder,AC conductivity,FT-IR,XRD,PC/PEO blend
更新于2025-09-04 15:30:14
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Spin coated multilayered CuO/ZnO films with high output power under irradiation
摘要： Thin films of pure CuO, pure ZnO and CuO/ZnO multilayers were synthesized using the spin coating technique. CuO and ZnO layers were spin coated for 30 s at speeds of 2000 and 1500 rpm, respectively. All the samples were subsequently annealed at 500 0C for one hour in air. Structural properties of films investigated using XRD patterns indicated the crystallization of single phase of CuO and ZnO. Optical band gaps of samples determined by UV-Visible spectrums were in the range of the band gaps of CuO and ZnO. The main objective of the preparation of multilayered CuO/ZnO was enhancing the output power by combining wide band gap and narrow band gap materials. CuO with higher photocurrent and ZnO with higher photovoltage were employed to achieve this task. Photocurrent, photovoltage and impedance were measured in order to investigate the electrical properties of these samples. A liquid junction photocell with electrolyte potassium iodide (KI) was employed to measure photovoltaic properties. A multilayer with ZnO as the top layer provides a higher output power of 3.6 μW/cm2 compared to the output power of a multilayer with CuO as the top layer (1.1 μW/cm2). This is the highest output power reported for a multilayer of CuO/ZnO without any dye coating in KI electrolyte. The highest output power of our multilayered samples is more than twice the previously reported highest output powers of pure CuO and pure ZnO thin film samples without dye coating. Chemical properties of samples were confirmed by FTIR. Crystallite sizes were in the range from 23 to 28 nm. Impedance curves of the samples were measured under dark and light conditions. Two semicircles could be observed at Nyquist plots of both multilayer samples.
关键词： photovoltaic properties,spin coating,XRD,Cupric Oxide,multilayers,Zinc Oxide
更新于2025-09-04 15:30:14
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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
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Investigation of structural, optical and morphological properties of InGaN/GaN structure
摘要： In this study, InGaN/GaN structure is investigated in the temperature range of 300–500?°C with steps of 50?°C. InGaN/GaN multi-quantum well structure is deposited on c-orientated sapphire wafer by metal organic chemical vapour deposition method. All the parameters except for temperature kept constant during growth period. InGaN/GaN structures with different In content are investigated by XRD technique. Their structural, optical and morphological characteristics are determined by high resolution X-ray diffraction, Fourier transform spectroscopy (FTIR), photo luminescence (PL), transmission and atomic force microscopy (AFM). According to FTIR and PL spectra’s, it is noticed that band gap values coincide with blue region in the electromagnetic spectrum. As a result of transmission measurements it is seen that light is completely absorbed by the sample at approximately 390?nm. Using XRD technique, dislocation densities and strain are calculated. Full width at half maximum of the XRD peak values gained from X-ray diffraction are used in an alternative method called William-son–Hall (W–H). Using W–H method, lateral and vertical crystal lengths and tilt angles are determined. Surface roughness parameters are investigated by AFM. Different properties of GaN and InGaN layers are compared as dependent on increasing temperature. According to AFM images it is seen that these structures have high surface roughness and large crystal size. All the results yielded from the mentioned methods are in good agreement with the previous works done by different authors.
关键词： FTIR,MOCVD,XRD,AFM,PL,InGaN/GaN
更新于2025-09-04 15:30:14