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New luminescent heterometallopolymers [(Au‐C6F5)m(AgOSO2CF3)n (PVP)] with different Au:Ag molar ratios were synthesized. The luminescent emissions of these polymers are strongly dependent on the temperature, excitation wavelengths, and the Au(I):Ag(I) molar ratio. The incorporation of a precise amount of Ag(I) atoms in the backbone of [(Au‐C6F5)m(PVP)] metallopolymer allows a controlled tuning of the emission energy in the green‐blue range. [ABSTRACT FROM AUTHOR]

Poly‐1‐vinyl‐1,2,4‐triazole (PVT)‐based materials with silver nanoparticles are promising antibacterial products. The metal nanoparticles with controllable sizes were obtained by radiation‐induced reduction of the dispersions of complexes of PVT with silver ions. Formation of the silver nanoparticles in aqueous suspensions irradiated at pH 6.0, 2.5, and 2.0 was studied using methods of UV–VIS spectroscopy and transmission electron microscopy. UV–VIS spectroscopy has detected a change in the efficiency of interaction between protonated or non‐protonated PVT units and the surface of silver nanoparticles. The interaction of macromolecules with the metal surface under different degrees of protonation of PVT functional groups afforded the nanoparticles with a narrow size distribution and an average size from 3 to 10 nm. An increase in the acidity also leads to a decrease in the ratio of the generation/growth of nanoparticles. The radiation approaches both provide the synthesis of the nanoparticles of controlled sizes and permits to obtain the nanocomposites containing no impurities of chemical reducing agents. The nanocomposites obtained exhibit high antibacterial activity against various bacterial strains, which depends on the size of silver nanoparticles. [ABSTRACT FROM AUTHOR]

Poly(styrene@N‐isopropylmethacrylamide‐methacrylic acid) [P (St‐NM)] microgels were prepared via seed facilitated emulsion polymerization process. In situ reduction of silver ions was carried out to generate Ag nanoparticles in the voids of shell region of polymer microgels. Synthesized P (St‐NM) and Ag‐P (St‐NM) particles were characterized by UV–Vis spectroscopy, transmission electron microscopy (TEM), Fourier‐transformed infrared spectroscopy (FTIR), and X‐ray diffraction (XRD). The stability of Ag nanoparticles within P (St‐NM) system over the wide range of pH and temperature is also a part of this study. Thus, prepared Ag‐P (St‐NM) was tested for its catalytic efficiency against reduction of K2Cr2O7 using formic acid (FA) as reductant. Factors affecting catalytic efficiency of Ag‐P (St‐NM) system towards transformation of Cr+6 to Cr+3 were investigated. Other toxic chemicals can also be reduced using same catalytic system. [ABSTRACT FROM AUTHOR]

The present paper reports a facile in situ synthesis strategy for the production of MnFe2O4@PDA‐Ag magnetically recyclable core–shell nanospheres by the deposition of silver nanoparticles (AgNPs) to the surface of MnFe2O4@PDA nanocomposites through the reduction of silver ions by the outer polydopamine (PDA) layer. The deposition of AgNPs over MnFe2O4@PDA was validated by scanning electron microscopy–energy‐dispersive X‐ray spectroscopy (SEM‐EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and vibrating sample magnetometer (VSM) analysis. The catalytic reduction performance of the obtained MnFe2O4@PDA‐Ag nanospheres were tested over model organic dye pollutants (i.e., methylene blue [MB] and 4‐nitrophenol [4‐NP]) by sodium borohydride. Notably, the as‐prepared MnFe2O4@PDA‐Ag nanocatalyst exhibited significantly enhanced catalytic activity for the reduction of MB (296.52 s−1 g−1) and 4‐NP (92.02 s−1 g−1) compared with the other types of similar Ag‐ and PDA‐based catalytic systems in the recent literature. Moreover, the MnFe2O4@PDA‐Ag nanocatalyst showed excellent recyclability, ease of magnetic separation, and rapid and higher recovery ability with insignificant loss in their catalytic efficiencies even after several cyclic uses. The PDA coating on the surface of MnFe2O4 NPs allocates the surface functionalization for the building of novel catalyst systems. This work presents a simple and practicable for the synthesis of MnFe2O4@PDA‐Ag nanospheres that could have a great potential for the treatment of organic pollutants in wastewater and variety of applications in catalysis. [ABSTRACT FROM AUTHOR]

Materials having both magnetic and catalytic properties have shown great potential for practical applications. Here, a reduced graphene oxide/iron oxide/silver nanohybrid (rGO/Fe3O4/Ag NH) ternary material was prepared by green synthesis of Ag on pre-synthesized rGO/Fe3O4. The as-prepared rGO/Fe3O4/Ag NH was characterized using Fourier transform infrared spectroscopy, X-ray diffractometry, Raman spectroscopy, vibrating sample magnetometry, transmission electron microscopy and energy-dispersive X-ray spectroscopy. rGO sheets were covered with Fe3O4 (8-16 nm) and Ag (18-40 nm) nanoparticles at high densities. The mass percentages were 13.47% (rGO), 62.52% (Fe3O4) and 24.01% (Ag). rGO/Fe3O4/Ag NH exhibited superparamagnetic behavior with high saturated magnetization (29 emu g−1 at 12 kOe), and efficiently catalyzed the reduction of 4-nitrophenol (4-NP) with a rate constant of 0.37 min−1, comparable to those of Ag-based nanocatalysts. The half-life of 4-NP in the presence of rGO/Fe3O4/Ag NH was ca 1.86 min. rGO/Fe3O4/Ag NH could be magnetically collected and reused, and retained a high conversion efficiency of 94.4% after the fourth cycle. rGO/Fe3O4/Ag NH could potentially be used as a magnetically recoverable catalyst in the reduction of 4-NP and environmental remediation. [ABSTRACT FROM AUTHOR]

Green tea extract having many phenolic hydroxyl and carbonyl functional groups in its molecular framework can be used in the modification of Fe3O4 nanoparticles. Moreover, the feasibility of complexation of polyphenols with silver ions in aqueous solution can improve the surface properties and capacity of the Fe3O4@green tea extract nanoparticles (Fe3O4@GTE NPs) for sorption and reduction of silver ions. Therefore, the novel Fe3O4@GTE NPs nano-sorbent has potential ability as both reducing and stabilizing agent for immobilization of silver nanoparticles to make a novel magnetic silver nanocatalyst (Fe3O4@GTE/Ag NPs). Inductively coupled plasma analysis, transmission and scanning electron microscopies, energy-dispersive X-ray and Fourier transform infrared spectroscopies, and vibrating sample magnetometry were used to characterize the catalyst. Fe3O4@GTE/Ag NPs shows high catalytic activity as a recyclable nanocatalyst for the reduction of 4-nitrophenol at room temperature. [ABSTRACT FROM AUTHOR]

This work reports the preparation of multiwalled carbon nanotube/pramipexole/Ag (CNT/pra/Ag) as a novel antibacterial agent, in which pramipexole groups are utilized as linkers to secure Ag nanoparticles to carbon nanotube surfaces without agglomeration. The resulting CNT/pra/Ag sample was characterized by performing transmission and scanning electron microscopy, wavelength- and energy-dispersive X-ray, X-ray diffraction, Fourier transform infrared, inductively coupled plasma and Raman measurements. Using this approach, monodisperse spherical Ag nanoparticles in CNT/pra/Ag have narrow size distributions with average diameters of ca 3-8 nm. The antibacterial activity of CNT/pra/Ag was investigated against bacterial species Staphylococcus aureus, methicillin-resistant S. aureus, Pseudomonas aeruginosa and Escherichia coli using the paper-disc diffusion method and by determining the minimal inhibitory concentration. CNT/pra/Ag showed better inhibitory activity towards Gram-positive bacteria than Gram-negative bacteria in this study, which indicates its potential as an antibacterial material for laboratory and medical purposes. [ABSTRACT FROM AUTHOR]

Recent advances in photocatalysis focus on the development of materials with hierarchical structure and on the surface plasmon resonance (SPR) phenomenon exhibited by metal nanoparticles (NPs). In this work, both are combined in a material where size‐controllable Ag‐NPs are uniformly loaded onto the hierarchical microporous and mesoporous and nanocolumnar structures of ZnO, resulting in Ag‐NP/ZnO nanocomposites. The embedded Ag‐NPs slightly decrease the hydrophobicity of fibrous ZnO, improve its wettability, and increase the absorption of formaldehyde (H2CO) onto the photocatalyst, all of this resulting in excellent photodegradation of formaldehyde in aqueous solution. Besides, we found that Ag‐NPs with optimal size not only accelerate the charge transfer to the surface of ZnO, but also strengthen the SPR effect in the intercolumnar channels of fibrous ZnO particles combining with high concentration of photo‐generated radical species. The micro‐to‐mesoporous ZnO is like a nanoarray packed Ag‐NPs. With Ag‐NPs of diameter 2.5 < ϕ < 6.5 nm, ZnO exhibits the most superior photodegradation rate constant value of 0.0239 min−1 with total formaldehyde removal of 97%. This work presents a new feasible approach involving highly sophisticated Ag‐NP/ZnO architecture combining the SPR effect and hierarchically ordered structures, which results in high photocatalytic activity for formaldehyde photodegradation. [ABSTRACT FROM AUTHOR]