Browsing by Subject "Bimetallic nanoparticles"

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Open Access
Facile synthesis of bimetallic nanoparticles with diverse nanostructures using metal acetylacetonates
(2024-01) Sayma, Dalya M. F.
Bimetallic nanoparticles (NPs) have become a fundamental subject in the field of nanoscience and inorganic chemistry. Owing to the fascinating optical and catalytic properties that rise from their synergetic effect, plasmonic-catalytic bimetallic NPs, in particular, are employed in a myriad of applications such as catalysis, sensing and photocatalysis. Optical properties of plasmonic NPs such as gold or silver NPs are based on the localized surface plasmon resonance (LSPR) in the visible spectral range. Plasmonic NPs enhance the localization of electromagnetic fields, converting light to hot carriers or heat that can be used to drive chemical reactions. On the other hand, catalytic metals, which have d-bands close to the Fermi-level, make strong binding to reactants and lower the activation energy of chemical reactions. The properties of plasmonic-catalytic bimetallic NPs such as efficiency or product selectivity in the chemical reaction do not only rely on factors like size and composition of metal NPs, but more importantly, on the types of nanostructures formed. Herein, several nanostructures were synthesized by developing a facile approach using metal acetylacetonates. The synthesized NPs include bare silver NPs, bare palladium NPs, Pd@Ag core-shell NPs, Pd@Ag nanowires, Ag-Pd alloyed core-satellite NPs, Ag-Pt alloyed nano-stars and concave nano-cubes, and trimetallic AgPdPt NPs. In this study, it was found that the temperature, composition of metal components, and amount of capping and reducing agents play a key role in the synthesis of different types of bimetallic NPs. This study is important in the field of nanochemistry as it provides a novel synthesis method for generating plasmonic-catalytic bimetallic NPs.
Open Access
Immobilized Pd-Ag bimetallic nanoparticles on polymeric nanofibers as an effective catalyst: Effective loading of Ag with bimetallic functionality through Pd nucleated nanofibers
(Institute of Physics Publishing, 2018) Ranjith, K. S.; Celebioglu A.; Uyar, Tamer
Here, we present a precise process for synthesizing Pd-Ag bimetallic nanoparticles (NPs) onto polymeric nanofibers by decorating Pd-NPs through atomic layer deposition followed by a chemical reduction process for tagging Ag nanostructures with bimetallic functionality. The results show that Pd-NPs act as a nucleation platform for tagging Ag and form Pd-Ag bimetallic NPs with a monodisperse nature with significant catalytic enhancement to the reaction rate over the bimetallic nature of the Pd-Ag ratio. A Pd-NP decorated polymeric nanofibrous web acts as an excellent platform for the encapsulation or interaction of Ag, which prevents agglomeration and promotes the interaction of Ag ions only on the surface of the Pd-NPs. We observed an effective reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride (NaBH4) to access the catalytic activity of Pd-Ag bimetallic NPs on a free-standing flexible polymeric nanofibrous web as a support. The captive formation of the polymeric nanofibrous web with Pd-Ag bimetallic functionality exhibited superior and stable catalytic performance with reduction rates of 0.0719, 0.1520, and 0.0871 min-1 for different loadings of Ag on Pd decorated nanofibrous webs such as Pd/Ag(0.01), Pd/Ag(0.03), and Pd/Ag(0.05), respectively. The highly faceted Pd-Ag NPs with an immobilized nature improves the catalytic functionality by enhancing the binding energy of the 4-NP adsorbate to the surface of the NPs. With the aid of bimetallic functionality, the nanofibrous web was demonstrated as a hybrid heterogeneous photocatalyst with a 3.16-fold enhancement in the reaction rate as compared with the monometallic decorative nature of NaBH4 as a reducing agent. The effective role of the monodisperse nature of Pd ions with an ultralow content as low as 3 wt% and the tunable ratio of Ag on the nanofibrous web induced effective catalytic activity over multiple cycles.