Papers by Keyword: Photocatalytic

Abstract: Industrialization has led to widespread aquatic contamination, with dyes being among the most prominent pollutants found in various water bodies. Major contributors to dye pollution include the textile, printing, leather, cosmetics, and chemical industries, with the textile industry alone being responsible for approximately 13% of the dyes released into aquatic environments. This study focuses on comparing the photocatalytic degradation performance of synthesized catalysts prepared in the presence of biopolymers. Pullulan was selected as a capping agent to aid the synthesis process and promote the formation of nanosized catalysts. Three types of catalysts, namely copper oxide, zinc oxide, and a composite of both, were synthesized, and their performance was evaluated through the photocatalytic degradation of methylene blue. Among the three, zinc oxide demonstrated the highest degradation efficiency (99%), followed by the composite (27%), while copper oxide exhibited negligible photocatalytic activity (14%). Further optimization of the best-performing catalyst (zinc oxide) was conducted by varying parameters such as catalyst dosage (0.05-0.15g) and solution pH (5-9). The results showed that zinc oxide achieved the highest degradation under acidic conditions (pH 5) with a dosage of 0.15 g, requiring only 70 minutes to reach nearly 100% degradation. Overall, this study provides valuable insights into the influence of catalyst type on the photocatalytic degradation of methylene blue.

Abstract: Carbon nitride (C₃N₄) has gained attention from scientists due to its potential applications as a catalyst for organic synthesis, electrodes, photocatalysts, and hydrogen storage materials. Using C₃N₄ as a photocatalyst for the glycerol-to-hydrogen reaction could offer many development advantages. Pure C₃N₄ has several shortcomings as a photocatalyst, so modifications are needed to enhance its properties and characteristics. Converting C₃N₄ into nanosheet form and adding Zirconium doping are solutions to improve its performance. The nanosheet form increases the surface area by creating thin sheet structures, while Zirconium doping is chosen because it can improve the conductivity and mechanical properties of the catalyst. This research focuses on characterizing catalysts with varying doping levels (5%, 10%, 15%, 20%, and 27%). Tests conducted include BET analysis, XRD, and UV-Vis DRS. Results show that the sample with 20% doping performs the best, with a specific surface area of 46.087 m²/g. Crystallinity was assessed with values of 2Ө = 27.8426°, 31.6712°, 45.4188°, and 56.4368°. The band gap energy was determined to be 3.067 eV. These findings are then compared with previous research.

Abstract: Nanoparticles are one of the widely studied research topics. ZnO nanoparticles have numerous benefits, such as photocatalysts and antibacterial applications. Methylene blue, which a highly dangerous and pollutes the environment and human health, is mostly used as a coloring dye in the textile industry. The use of biodegradation to treat textile waste is time-consuming and less effective. Applying photocatalysts using semiconductor materials is a more efficient method than conventional approaches for decomposing organic waste. One environmentally friendly method is green synthesis, which involves the use of microorganisms, enzymes, and plant extracts in the fabrication process. In this study, the green synthesis using chemical reduction of Premna serratifolia linn leaf extract was used to produce ZnO nanoparticles. The objective of this study is to investigate the effect of temperature on the fabrication of ZnO nanoparticles and their photocatalytic performance. Zinc nitrate tetrahydrate was used as a precursor, and the furnace temperature was varied at 400, 500, and 600 °C. The obtained ZnO was then tested using scanning electron microscopy (SEM), X-ray diffractometry (XRD), and Fourier transforms infrared spectrophotometry (FTIR). Moreover, the photocatalytic test was evaluated by examining the degradation efficiency of methylene blue using UV light. The XRD analysis indicated that the ZnO nanoparticles had crystallite sizes ranging between 44-60 nm. The SEM morphological test showed that the ZnO particles had a nano-sized spherical shape. The FTIR test results demonstrated the presence of ZnO peaks around 520 cm^‑1. The performance of photocatalytic activity under UV light irradiation was significantly affected by tuning the temperatures. It was observed that the photocatalytic activity increased with increasing temperature, and methylene blue degradation efficiency reached 50% at a temperature of 600 °C. The ability of ZnO as a photocatalyst material was also evaluated by recycling the used material two times, where there was no significant change in photocatalytic performance.

Abstract: Decorated Fe₂WO₆ onto SrTiO₃ nanocubes (Fe₂WO₆/SrTiO₃) composites were fabricated by a two-step hydrothermal technique. Some spectroscopic techniques were adopted to delve the catalyst samples. The composite manifested a prominent antibacterial effect toward Escherichia Coli and Bacillus cereus bacteria. Importantly, the as-fabricated composite was testified to exhibit good photodegradation of chlortetracycline hydrochloride under visible light. The eminent performance of the composite was ascribed to not only the excellent absorption of visible light, but also due to the synergistic effect of S-scheme heterojunction which endowed for the high yield of the active species for the pollutant and microorganism destruction. Our study implied that Fe₂WO₆/SrTiO₃ composites can be a potential bifunctional option for remediating microbial-polluted water.

Abstract: It is well known that adding the appropriate amount of Ag to semiconductor materials can enhance photocatalytic performance. In our previous study, the addition of Ag nanoparticles to ZnO enhanced the photocatalytic activity. The best photocatalytic performance was obtained when Ag content was 5 wt%. However, the effect of a carrier gas flow rate has not been investigated. The objective of this study is to investigate the effect of carrier gas flow rate on the morphology of the ZnO-Ag nanocomposites as well as the photocatalytic activity of the produced nanocomposites. ZnO-Ag nanocomposite was fabricated by a one-step process using flame pyrolysis and the produced nanocomposites were characterized by a scanning electron microscope (SEM) and X-Ray Diffraction (XRD) analysis. The photocatalytic performance was evaluated by measuring the degradation of methylene blue under UV light irradiation. SEM images indicated that the morphology of ZnO-Ag nanocomposites has a spherical shape with a particle diameter of around 65 nm. Moreover, increasing the flow rate will increase the particle size of the produced nanocomposites. The photocatalytic test was determined based on the rate constant of MB degradation efficiency under UV light irradiation, where the photocatalytic activity decreased when the carrier gas increased. Finally, the produced nanocomposites were also tested several times (recycling test), where photocatalytic performance showed that the degradation value of methylene blue for each recycle did not vary much with the variable before being recycled.

Abstract: The photocatalytic activity of NiZnFe₂O₄/TiO₂ core-shell gg nanocrystalline was carried out. The NiZnFe₂O₄/TiO₂ core-shell was synthesized using co-precipitation method with various concentrations 1:0, 1:1, 1:2, 1:3, 1:4, and 1:5. X-ray diffraction spectra pattern showed crystallite size at various concentrations 1:0, 1:1, and 1:3, which of 5.00 nm, 4.90 nm, and 10.81 nm, respectively. The morphology of NiZnFe₂O₄ nanocrystalline was characterized by transmission electron microscopy which confirmed that the sample undergoes agglomeration with not uniform particle shape. The average particle size of the nanocrystalline was 10.26 nm. Fourier transform infra-red showed functional groups such as Ti-O-Ti, M-O_tetra, and M-O_octa at 1473.62, 563 - 586, and 401- 424 cm^-1. In addition, the presence of Ti-O-Ti and M-O functional groups indicates NiZnFe₂O₄/TiO₂ core-shell has been formed. The absorbance spectrum of the NiZnFe₂O₄/TiO₂ core-shell has an energy band gap in the range of 2.1 – 3.3 eV. The results of the Vibrating sample magnetometer showed saturation magnetization and coercivity values ​​in the range of 12.4 – 22.9 emu/gr and 47 - 55 Oe, which were correlated as soft magnetic properties. NiZnFe₂O₄/TiO₂ was successfully degraded Methylene Blue that reach 99.8% under UV light irradiation. The addition of TiO₂ increases degradation, TiO₂ acts as a trapping state that inhibits electron-hole recombination which can prolong the reaction time between free electrons and MB solution molecules. This study revealed the high potential of NiZnFe₂O₄/TiO₂ core-shell nanocrystalline in photocatalytic application.

Abstract: NiZnFe₂O₄/SiO₂ was successfully synthesized by green-synthesis method using moringa oleifera with various concentrations of 0%, 5%, 10%, 15%, 20%, 30% and 50%. X-Ray diffraction spectra showed that the crystal structure of NiZnFe₂O₄/SiO₂ has a mixed cubic spinel structure. Fourier-transform infrared spectra indicated the C-H functional group at 2374-2378 cm^-1 which identified that green synthesis has been successfully carried out, Si-O-Si (siloxane) at 1072-1100 cm^-1 which was confirmed as NiZnFe₂O₄/SiO₂ which allows modification silica was successfully encapsulated in NiZnFe₂O₄/SiO₂ confirmed by the presence of Si-O-Si groups at 1065-1086 cm^-1. The result of the vibrating sample magnetometer NiZnFe₂O₄/SiO₂ showed saturation magnetization and coercivity was 9-18 emu/g and with at 44-50 Oe respectively, so it is detected as superparamagnetic. The UV-Vis absorbance spectrum of NiZnFe₂O₄/SiO₂ for all concentrations was at 194 nm with a band gap of energy ranging from 3.14 to 3.34 eV which indicates good absorption. The Photocatalytic process with NiZnFe₂O₄/SiO₂ using organic dye methylene blue was available to do up to 94%.

Abstract: Microplastic is the most problematic persistent pollutants in the environment despite of its unique properties for various life application. The objective is to investigate the feasibility and practicability of the nanostructured TiO₂ coupling with noble metal in removal polypropylene (PP) microplastics. The TiO₂ nanowires (NWs) were synthesized by thermal oxidation of Ti foil under various mixed oxidation environments. TiO₂ NWs were successfully grown uniformly and with full coverage over the foil under the condition of ramping in KOH mist and soaking in water vapour at 700 °C for 120 minutes. Heterojunction photocatalyst of Ag/TiO₂ NWs was formed using wet impregnation method. Small quantity of Ag nanoparticles (NPs) was attached onto the TiO₂ nanowires. The photocatalytic efficiency of the synthesized Ag/TiO₂ NWs photocatalyst was tested upon removal of PP microplastic from non-static water bodies under UV irradiation. Coupling Ag NPs with TiO₂ NWs have better photocatalytic performance than those without Ag NPs from the reduction of weight loss and the possibility of presence of carbonyl group.

Abstract: Photocatalysts that can utilize sunlight energy have attracted attention. In this study, g-C₃N₄ and mesoporous SiO₂@TiO₂ particles were mixed by hydrothermal synthesis. g-C₃N₄ was made by a simple method of directly heating melamine. Mesoporous SiO₂@TiO₂ was prepared using the stover method. These two types of particles were then mixed by hydrothermal synthesis. Hydrothermal synthesis reduced the size of the g-C₃N₄ particles, and they bound more closely with the TiO₂ particles. The degradation of methylene blue dye by visible light was performed to evaluate the organic degradation of the mixed particles. In addition, the mixed particles were formed into a thin film by the spin-coating method. The film's methylene blue degradation performance and the film's power generation performance in a battery were evaluated. The film showed high convenience in the practical application of photocatalytic degradation of organic pollutants because it can be easily separated from the treated liquid after organic matter degradation.

Abstract: The magnetic photocatalyst of CoZnFe₂O₄/SiO₂ nanoparticles has been synthesised to degrade methylene blue (MB) dye. The CoZnFe₂O₄ nanoparticles were prepared by co-precipitation method under mechanical stirring and coated with SiO₂ by stöber method using Na₂SiO₂ with various concentrations of 5%, 10%, 15%, 20%, 30%, and 50%. The properties of CoZnFe₂O₄/SiO₂ was confirmed by x-ray diffraction (XRD), Fourier transforms infrared (FTIR), vibrating sample magnetometer (VSM), and UV-Visible spectroscopy. XRD analysis revealed that CoZnFe₂O₄ had the spinel ferrite phase structure with crystalite size of 17.0 nm, and then after coating with SiO₂, the size became 17.1 nm. FTIR clearly show an M-O octahedral vibrational bond found with a wavelength of 378 cm^-1, O-Si-O, Si-OH, and Si-O-Fe at 1087, 794, and 570 cm^-1, respectively. The saturation magnetization (Ms) and coercivity of CoZnFe₂O₄/SiO₂ was 29.0 emu/g and 251.9 Oe, respectively. Furthermore, the results of UV-Visible data presented that the absorption edges CoZnFe₂O₄/SiO₂ in the range of 190 - 600 nm. The percentage of CoZnFe₂O₄ degradation is 88.4%, while after coted SiO₂ 50%, the degradation becomes 98.9%.