Orhan Baytar

Green‐synthesized FeO nanoparticles (via pistachio leaf extract) were modified with Co and Ru to produce Co–FeO and Ru–FeO nanocatalysts. Their catalytic performances were evaluated in hydrogen generation through NaBH ₄ hydrolysis. Kinetic studies revealed distinct reaction behaviors: Co–FeO followed a zero‐order model, whereas Ru–FeO exhibited a fractional reaction order of 0.35. Despite these differences, both catalysts showed similar activation energies, calculated as 52.7 kJmol ⁻¹ for Co–FeO and 52.9 kJmol ⁻¹ for Ru–FeO. Transmission electron microscopy indicated that the pristine FeO nanoparticles had particle sizes of 10–20 nm, while Co modification slightly increased the particle size to 20–25 nm. In contrast, Ru modification resulted in a broader particle size distribution ranging from 25 to 75 nm. The crystallite sizes estimated from the XRD data using the Scherrer equation were 2.5 nm for FeO, 2.0 nm for Co–FeO, and 1.8 nm for Ru–FeO. The results demonstrate that metal modification significantly influences the structural and catalytic properties of FeO nanoparticles. Notably, Ru–FeO exhibited enhanced catalytic activity and faster hydrogen generation, while Co–FeO provided more stable catalytic performance during the reaction. These findings highlight the potential of metal‐modified FeO nanocatalysts for efficient and sustainable hydrogen production.

This study was conducted to evaluate the effect of boron-containing and boron-free silver nanoparticles obtained from okra stems on the vase life of Tulip sinfonie (Tulipa hybrida) cut flowers. Silver nanoparticles with and without boron at 5, 10, and 20 mg/l were obtained from okra stems. The effects of these silver nanoparticles on the vase life, relative fresh weight, and daily vase solution uptake of Tulip Sinfonie cut tulip flowers were evaluated. The longest vase life was obtained from the boron-doped 20 mg/lt application with 7.33 days, while the lowest vase life was obtained from the control group. Statistically significant differences were observed between the applications in daily vase solution uptake and relative fresh weight change. Vase solution uptake was better in boron-doped vases compared to those without boron, thus extending vase life. As with many other studies on the use of silver nanoparticles in vase solutions, this study also showed that the antibacterial properties of the nanoparticles extended vase life by reducing antimicrobial activity. The rate of relative fresh weight decrease was slow throughout the study. Previous studies on vase life have also found that relative fresh weight increased for a certain period at the beginning of the study and then decreased. Furthermore, this study is considered important because it is the first study to add boron to silver nanoparticles in relation to vase life. Vase life, relative fresh weight, and daily vase solution intake were observed to be better in boron-doped applications. It was observed that the addition of boron further improved water uptake. The longest vase life was obtained from high-dose applications of silver nanoparticles. It is thought that it would be beneficial to test different doses of metal nanoparticles such as copper and zinc, and sugar application in the vase solution in future studies.

Green synthesis has gained considerable attention as a sustainable and environmentally friendly approach to nanomaterial fabrication. In this study, zinc oxide (ZnO) nanoparticles (NPs) were synthesized using an aqueous extract of Siirt pistachio thin shells, which acted as a natural reducing, stabilizing, and capping agent due to its rich phytochemical content. This green route eliminates the use of toxic chemicals, offering a cost-effective and scalable alternative for nanoparticle production. The synthesized ZnO NPs were characterized by SEM, TEM, XRD, EDX, and FTIR analyses, revealing predominantly spherical morphology with an average crystallite size of approximately 20 nm calculated by the Debye-Scherrer equation. Photocatalytic activity was assessed through methylene blue (MB) dye degradation under visible light, following a pseudo-first-order kinetic model with a rate constant of 0.0462 min^-1, while antibacterial performance was evaluated via disk diffusion, showing significant inhibition zones against various pathogenic bacteria. The results demonstrate that the ZnO NPs exhibit excellent photocatalytic and antimicrobial properties, highlighting the potential of this green synthesis method for wide-ranging applications in environmental remediation, antimicrobial surface coatings, food packaging, cosmetics, and biomedical technologies.

In this study, activated carbon was synthesized using hydrochar obtained from lentil stalks, which is generally evaluated as animal feed, by hydrothermal method. Thus, a low value-added biomass source was transformed into a higher value-added product. Activated carbon was synthesized using ZnCl₂ activator by chemical activation method and then carbon molecular sieve was obtained by chemical vapor deposition method. Characterization of synthesized activated carbon and carbon molecular sieves was carried out using FTIR, BET and SEM analysis techniques. SEM analysis results showed that synthesized activated carbon had a more porous structure compared to hydrochar and raw lentil stalk. Synthesized activated carbon and carbon molecular sieve were used in methylene blue adsorption for the removal of organic pollutants. In this process, parameters such as pH and initial concentration affecting adsorption performance were investigated and adsorption kinetics were determined. Methylene blue adsorption equilibrium data were applied to Langmuir and Freundlich isotherms and it was determined that the system showed the best fit to Langmuir isotherm. The maximum adsorption capacity (qmax) was determined as 98 mg/g for activated carbon and 87 mg/g for carbon molecular sieve. In addition, it was concluded that the methylene blue adsorption kinetics for both adsorbents fit the pseudo-second-order kinetic model. This study reveals that agricultural wastes such as lentil stalks can be effectively used in reducing environmental pollution by converting them into high-performance adsorbent materials.

This study presents the green synthesis of copper-doped zinc oxide (Cu-doped ZnO) nanoparticles using tobacco stem (TS) extract. The environmentally friendly synthesis method ensures distinct features, high efficiency, and applicability in various fields, particularly in solar cell technology and photocatalytic applications. ZnO nanostructures are investigated due to their unique properties, cost-effectiveness, and broad range of applications. The nanoparticles are synthesized with varying Cu concentrations, and their structural, morphological, and compositional characteristics are thoroughly analyzed. The Cu-doped ZnO nanoparticles exhibit improved properties, such as increased surface area and reduced particle size, attributed to the incorporation of Cu dopants. The green synthesis approach using TS extract serves as a stabilizing agent and avoids the toxicity associated with chemical methods. Characterization techniques including SEM, TEM, EDX, FTIR, and XRD confirm the successful synthesis of the nanoparticles. Photocatalytic degradation studies reveal that the 5% Cu-doped ZnO exhibits the highest photocatalytic activity against methylene blue, attributed to synergistic effects between Cu and ZnO, including oxygen vacancy and electron-hole pair recombination rate suppression. The photocatalytic mechanism involves the generation of superoxide and hydroxyl radicals, leading to methylene blue degradation. Furthermore, the Cu-doped ZnO nanoparticles demonstrate promising photovoltaic performance, with the optimal efficiency observed at a 5% Cu concentration. The study suggests that Cu-doped ZnO has the potential to enhance solar cell efficiency and could serve as an alternative material in solar cell applications. Future research should focus on refining Cu-doped ZnO for further improvements in solar energy conversion efficiency.