Papers by Keyword: Photocatalyst

Abstract: WO₃-based composite photocatalysts supported on tungsten disulfide (WS₂), urea, melamine, and graphene nanoplatelets (GNPs) were synthesized and characterized. The SEM micrographs showed that the support materials had a major impact on the composites' shape. While WO₃/WS₂ created layered sheets with scattered nanoparticles, WO₃/melamine and WO₃/urea showed porous and uneven morphologies. Strong interfacial contact was demonstrated by the homogeneous distribution of tiny WO₃ particles on crumpled graphene layers in WO₃/GNPs. W and O from WO₃, as well as S, N, and C elements from the corresponding supports, were verified by EDX. Methyl orange (MO) degradation under light irradiation was used to assess photocatalytic activity. Because of its huge surface area and improved electron mobility, WO₃/GNPs showed the highest degrading efficiency. The WO₃/WS₂ also displayed encouraging activity efficient due to the interfacial charge separation. On the other hand, WO₃/urea and WO₃/melamine performed moderately, most likely as a result of agglomeration and less conductive supports. With WO₃/GNPs emerging as a promising choice for dye degradation and wastewater treatment applications, these findings emphasize the importance of support materials in enhancing WO₃-based photocatalysts.

Abstract: This study investigates the synergistic potential of a novel heterojunction photocatalyst for methyl orange degradation. The photocatalyst comprises iron tungstate (FeWO₄) and graphitic carbon nitride (g-C₃N₄), engineered to exploit the distinct properties of each component for enhanced photocatalytic activity. The research systematically evaluates the performance of the synthesized FeWO₄/g-C₃N₄ composite in degrading methyl orange, with an emphasis on optimizing catalytic efficiency. The photocatalyst was characterized using advanced techniques, including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) to elucidate its structural and morphological properties. Key parameters such as loading concentrations were optimized to assess their influence on the photodegradation efficiency. Among tested compositions, 1.0 wt% FeWO₄/g-C₃N₄ achieved the highest degradation efficiency of MO at 78.04% within 180 minutes under UV irradiation. The heterojunction structure promoted effective charge separation, and further enhanced visible-light response. These results demonstrate the catalyst’s potential for sustainable water purification applications.

Abstract: The present study explores the green conflation of manganese dioxide (MnO₂) nanoparticles through a simple, Eco-friendly, and cost-effective system. This conflation process involves the response of potassium permanganate with an waterless splint excerpt of Hibiscus rosa- sinensis, serving as both a reducing and stabilizing agent. The green conflation system is profitable as it avoids poisonous chemicals, making it safer for both the terrain and implicit operations. The synthesized MnO₂ nanoparticles were considerably characterized using colorful logical ways. X-ray diffraction (XRD) analysis was used to confirm the liquid structure, while Fourier- transfigure infrared (FT- IR) spectroscopy handed sapience into the functional groups present in the material. UV-Visible spectroscopy was employed to study the optic parcels and band gap of the synthesized nanoparticles. Morphological details were observed through Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), which revealed the nanoparticles in globular shape and nanoscale size. One of the notable findings of this study is the photocatalytic effectiveness of the synthesized MnO₂ nanoparticles. Under visible light irradiation, these nanoparticles effectively degraded methyl orange color in waterless results, showcasing their eventuality as an effective photocatalyst. also, the synthesized MnO₂ nanoparticles demonstrated promising operations in the junking of organic adulterants from water, emphasizing their environmental significance. Overall, this study contributes to the development of sustainable nanomaterials for environmental remediation, particularly for wastewater treatment operations. The green conflation approach, combined with the excellent catalytic parcels of MnO₂ nanoparticles, underscores the material's eventuality for practical and large- scale operations.

Abstract: This paper explores the photocatalytic degradation of methyl orange (MO) dye using Mg doped ZnS nanoparticles, synthesized through a microwave assisted solvothermal method using zinc acetate, magnesium chloride, and thioacetamide. The x-ray diffraction (XRD) analysis confirmed the crystalline structure of the synthesized nanoparticles, indicating their suitability for photocatalytic applications. The optical absorption spectra revealed characteristic peaks in the UV-visible range, correlating with the nanoparticle’s effective light absorption capabilities. Furthermore, the energy bandgap, determined through Tauc plots, highlighted the material's potential for visible light induced photocatalysis, making it an efficient catalyst for dye degradation. Furthermore, the experiment involved preparing an aqueous MO solution, mixing it with Mg doped ZnS nanoparticles, and exposing it to visible light. The changes in the dye were observed using UV-Visible spectroscopy. This method showed that the nanoparticles effectively helped in degrading the dye up to 78.5%. The results indicate that Mg doped ZnS nanoparticles are effective for wastewater treatment, as they can effectively break down harmful dyes and can reduce environmental hazards, providing a sustainable and efficient method to treat industrial wastewater and ensure that released water is safer for the environment.

Abstract: Water pollution due to inadequate waste treatment causes damage to the ecosystem to various diseases in humans such as itching, and other skin diseases. One of the efforts to treat wastewater is photocatalyst. TiO₂ is one of the materials that can be used as wastewater treatment because it has good photocatalyst properties. However, TiO₂ has a wide band gap so that this material is only optimal at UV wavelengths. This can be overcome by adding Fe₃O₄ to TiO₂ which can help narrow the band gap and good magnetic properties so as to increase its photocatalyst activity. AC has advantages such as having a large cross-sectional area and being able to absorb waste well. AC/TiO₂/Fe₃O₄ nanocomposite was synthesized by hydrothermal method, then deposited on cork ball by spray coating and heating technique. SEM analysis showed that AC/TiO₂/Fe₃O₄ nanocomposites had an average size ranging from 124-225 nm and were successfully deposited on the surface of cork balls. In addition, the increase in porosity is related to the smaller diameter size with a large surface area. AC/TiO₂/Fe₃O₄ nanocomposites are dominated by the elements C, O, Ti, and Fe confirmed from EDX analysis. The smallest area is in sample 3 worth 1.39 m² /g and adsorbs the highest worth 116.33 nm so as to increase the effectiveness of the photocatalyst. Based on UV-Vis results, the absorption area of TiO₂ and Fe₃O₄ at a wavelength of 325 nm and in the AC/TiO₂/Fe3O₄ nanocomposite shows absorption between 295-330 nm. Fe₃O₄ has a relatively small band gap increase. The band gap energy of nanocomposite samples 1-5 decreased from 3.5 eV to 3.0 eV. O-H stretching vibrations in hydroxyl and carboxyl functional groups were confirmed with the addition of Fe₃O₄ mass. The most optimal river water photodegradation test results were shown in sample 3 with DO levels increased by 98.38%, phosphate levels decreased by 97.9% and water color decreased by 100%. After photodegradation for 150 minutes, the pH test results are still in accordance with the river discharge water quality standards. Overall, this material is very useful for the treatment of organic pollutants and wastewater.

Abstract: Fe₃O₄/CDots nanocomposites by combining Fe₃O₄ synthesized using Moringa oleifera extract and CDots produced from watermelon rinds have been successfully carried out. The Fe₃O₄/CDots nanocomposites with various CDots concentration was carried out through a sonication process. Test results using an X-ray diffractometer show that the crystal structure of the nanocomposite is a cubic inverse spinel. The presence of CDots resulted in a decrease in the size of Fe₃O₄ crystallites from 10.6 nm to 8.4 nm. Fourier transform infrared analysis confirmed the formation of Fe₃O₄/CDots nanocomposites with the appearance of Fe-O and C=C functional groups. The absorbance spectrum of the nanocomposite shows a dominant profile of Fe₃O₄/CDots, with an increase in band gap energy by the increase of CDots concentration in the range of 2.65 – 2.77 eV. The attachment of CDots to Fe₃O₄ is indicated by the luminescence produced in the photoluminescence test. The magnetic properties of Fe₃O₄ and Fe₃O₄/CDots nanocomposites show superparamagnetic characteristics with saturation magnetization values ​​of 54.2 emu/g and 34.3 emu/g, respectively. The magnetic properties of Fe₃O₄/CDots nanocomposites can support the separation feature of the liquid phase with the help of an external magnet. In testing photocatalytic activity, it was able to degrade methylene blue organic dye waste up to 96.7% in 10 minutes of UV radiation. Therefore, Fe₃O₄/CDots have potential as promising heavy metal removal agents and photocatalysts for effective and efficient environmental remediation.

Abstract: Research has been conducted on Fe₃O₄/PEG material applied as a photocatalyst. This research is motivated by the many textile industries that pollute the environment with their liquid waste disposal. The purpose of this research is to analyze the effect of concentration variation of Fe₃O₄/PEG nanocomposites that are green synthesized using Moringa oleifera extract on the photodegradation efficiency of Methylene Blue (MB) dye in water. The nanocomposites formed were then characterized through several techniques, including X-Ray Diffraction, Fourier Transform Infrared Spectroscopy, Vibrating Sample Magnetometer, and Ultraviolet-Visible (UV-Vis) spectrophotometry. Afterwards, the nanocomposites were tested in the MB photocatalytic process with various concentration to determine their effect on the degradation efficiency under UV irradiation. The material characterization results show that the nanocomposites has an inverse spinel cubic crystal structure with a crystallite size of 15.93±0.03 nm, and a lattice parameter of 8.17 Å. UV-Vis analysis showed an absorption peak at a wavelength of 322 nm with a direct energy band gap of 3.8 eV, and properties towards superparamagnetic with a saturation magnetization of 49.9 emu/g. Photocatalytic tests showed an increase in efficiency as the catalyst concentration increased, reaching the highest degradation of 68.2% at a mass of 0.09g. Therefore, this nanocomposite has potential as a photocatalyst.

Abstract: Lanthanum (La) and Nickel (Ni)-codoped Strontium Titanate (SrTiO₃) with the formula of Sr_1-xLa_xTi_1-yNi_yO₃ has been synthesized using the coprecipitation method. This research aimed to determine the effect of nickel and lanthanum co-doping on the photocatalytic activity of SrTiO₃. Here, the Ni concentration (y) was constant at 4%, while La concentrations (x) were varied at 1% and 2%. The synthesized samples were tested via X-ray diffraction (XRD) instrument to determine the crystal structure. It exhibited that the crystallite size reduced along with increased lanthanum concentration. The photocatalytic activity of Sr_1-xLa_xTi_1-yNi_yO₃ was observed under UV and Visible light irradiation against methylene blue (MB) pollutant dyes, and the absorption was measured via a UV-Vis spectrophotometer. It revealed that all samples succeeded in degrading MB solution under the two light sources with exposure times of 1, 2, 3, and 4 hours. Further, it was found that photocatalytic activity with UV lamp irradiation resulted in a better degradation percentage than visible light irradiation. The highest degradation about 60% was achieved by Sr_0.99La_0.01Ti_0.96Ni_0.04O₃ under UV light exposure for 4 hours.

Abstract: ZnO is a semiconductor material that is widely used for many applications in industries such as solar cells, dye-sensitized solar cells, food packaging, photocatalytic, anti-microbial, light-emitting diode devices, and gas sensors. In this study, ZnO nanoparticles (NPs) have been successfully synthesized using two methods, namely spray pyrolysis and a consecutive method. The consecutive method is a combination of sol-gel and spray drying methods. The objective of this study is to investigate the photocatalytic performance of ZnO fabricated using those methods. Both methods used the same precursor, zinc acetate dehydrate as a source of zinc, but with different solvents and additives. Based on the X-ray diffraction pattern, the ZnO NPs synthesized using spray pyrolysis and a consecutive method exhibited similar polycrystalline hexagonal wurtzite structures. The large crystal sizes of ZnO NPs were obtained using a consecutive method, sol-gel followed by spray drying, in comparison with those from the ZnO spray pyrolysis. In contrast, the particle size of ZnO prepared by the consecutive method was in a smaller range. The SEM analysis implied that the ZnO structures had surface defects. In the UV-driven photocatalytic degradation of methylene blue, ZnO produced by the consecutive method exhibited slightly higher degradation performance than ZnO spray pyrolysis. This performance was attributed to the larger crystal size of ZnO NPs, which provided a longer carrier movement at semiconductor surfaces and reduced electron-hole recombination. Additionally, ZnO NPs produced using the consecutive method underwent agglomeration that leads to a smaller contact surface with methylene blue, obstructing the degradation process.

Abstract: Lignin is a type of polymer with diverse functional groups that can be transformed into biofuels and various high-value chemicals. By utilizing light energy and operating at low temperatures, photocatalysis via Reactive Oxygen Species (ROS) becomes a promising strategy to develop further. However, the revelation of photocatalyst mechanisms in ROS production to improve the efficiency and effectiveness of lignin transformation is still limited. This study aims to determine the effect of Cu₂O/CuO quantum dots (QDs) concentration in the photocatalyst system on lignin depolymerization via ROS. The wet chemical method was used to synthesize Cu₂O/CuO QDs. The property determination of absorbance, crystallinity, and particle morphology is characterized using uv-vis, X-ray diffraction (XRD), and Transmission Electron Microscope (TEM) instrument. The ROS production was measured using a UV-vis instrument by varying the Cu₂O/CuO QDs concentration (1, 3, and 5 μM). The depolymerization sign was observed using a Fourier-Transform Infrared Spectroscopy (FTIR) instrument. The result shows that the synthesized material has a Cu₂O/CuO phase with an average particle size of 8 nm and a band gap value of 2.35 eV. The optimum ROS production activity was achieved at the Cu₂O/CuO QDs 3 μM concentration, reaching ten mM/sec. The FTIR result also confirms that the functional group transformation occurred. Overall, this study provides brief insight for further optimization of the lignin depolymerization photocatalysis process.