Browsing by Author "Karimi-Maleh, Hassan"

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Biogenic Platinum-Based Bimetallic Nanoparticles: Synthesis, Characterization, Antimicrobial Activity and Hydrogen Evolution
(Pergamon-elsevier Science Ltd, 2023) Darabi, Rozhin; Alown, Fadaa E. D.; Aygun, Aysenur; Gu, Qiang; Gulbagca, Fulya; Altuner, Elif Esra; Karimi-Maleh, Hassan
In this study, platinum-based silver nanoparticles (Pt@Ag NPs) were synthesized by the green synthesis method, and their catalytic effects on hydrogen production were investi-gated. The characterization measurements of the synthesized NPs were performed by TEM, UV-Vis, XRD, and FTIR. According to TEM characterization results, Pt@Ag NPs had an average size of 5.431 nm. In experiments based on catalytic reactions for hydrogen pro-duction, test measurements were made at different parameters. It was observed that as the concentrations of the substrate and catalysts increased, the catalytic reaction accelerated, and the hydrogen release increased. Likewise, it was determined that hydrogen production increased with increasing temperature in different temperature experiments. The turnover frequency, entropy, activation energy, and enthalpy values are calculated as 702.38 h-1,-160.5 J/mol.K, 32.48 kJ/mol, and 29.94 kJ/mol, respectively. According to the reusability test results, it was observed that the average reusability was found to be 85% after 5 cycles and it was confirmed that the NPs showed high-catalytic activity. In addition, the biological activities of Pt@Ag NPs, including antimicrobial, antioxidant and anticancer were tested. Pt@Ag NPs synthesized using Hibiscus sabdariffa (Hs) extract are thought to have the po-tential to be used in both biomedical and catalytic applications. The use of Pt@Ag NPs in the hydrogen production process shows great promise for green energy studies because it is environmentally friendly, non-toxic, and low cost. & COPY; 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Highly Active Pdpt Bimetallic Nanoparticles Synthesized by One-Step Bioreduction Method: Characterizations, Anticancer, Antibacterial Activities and Evaluation of Their Catalytic Effect for Hydrogen Generation
(Pergamon-elsevier Science Ltd, 2023) Aygun, Aysenur; Gulbagca, Fulya; Altuner, Elif Esra; Bekmezci, Muhammed; Gur, Tugba; Karimi-Maleh, Hassan; Sen, Fatih
Metallic nanoparticles (MNPs) have important applications in medicine and technology. Bimetallic NPs, which are among the metallic nanoparticles, are of great interest due to their properties. An innovative method by green synthesis has been developed to obtain bimetallic NPs. Aromatic plants are used in this synthesis method. One of the plants used for green synthesis is Nigella sativa and it has a unique place among plants for use as medicine. In this study, the synthesis of Palladium-Platinum bimetallic nanoparticles (PdPt NPs) and the catalytic, antibacterial, and anticancer activity of synthesized PdPt NPs by green synthesis method using Nigella sativa seed extract are reported. The synthesized PdPt NPs were characterized by Fourier Transform Infrared Spectrophotometer (FTIR), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), and UV-Vis spectrom-etry techniques. The catalytic activity of PdPt NPs was determined by performing sodium borohydride (NaBH4) hydrolysis experiments. According to the results obtained, Turnover Frequency (TOF), activation energy, entropy, and enthalpy values were found to be 1664.76 h-1, 13.93 kJ/mol,-119.02 J/mol.K, and 11.43 kJ/mol, respectively. It was determined that PdPt NPs are highly effective catalysts for hydrogen production. PdPt NPs (200 mu g/mL) were determined to have antibacterial activity of 57.58%, 64.42%, 48.68%, and 58.77% against Escherichia coli, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, and Bacillus subtilis bacteria, respectively. In addition, the cytotoxic effects of PdPt NPs, MTT against human breast cancer cell line (MDA-MB-231), human endometrial carcinoma cell line (Ishikawa, ISH), human cervical cancer cell line (HeLa), L929-Murine fibroblast cell line test, and IC50 values were calculated. The IC50 values of PdPt NPs applied against MDA-MB-231, ISH, and HeLa cancer cell lines were calculated as 9.1744 +/- 1.566 mu g/mL, 12.2431 +/- 1.132 mu g/ mL, 18.1963 +/- 1.730 mu g/mL, respectively. No significant cytotoxic effect was observed in healthy L929-murine fibroblasts. Green synthesis of PdPt NPs was determined to have significant advantages over chemical approaches. The biogenic PdPt NPs synthesized in this study suggest the design of bio-based bimetallic catalysts with high catalytic perfor-mance to prevent environmental pollution. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.