Journal ArticleDOI
A 'green' chitosan silver nanoparticle composite as a heterogeneous as well as micro-heterogeneous catalyst
A. Murugadoss,Arun Chattopadhyay +1 more
TLDR
The composite represents an ideal case of an environmentally friendly and stable catalyst, which works under heterogeneous as well as micro-heterogeneous conditions with the advantage of nanoscopic particles as the catalyst.Abstract:
In this paper, we report on the catalytic activity of a new metal nanoparticle–polymer composite consisting of Ag nanoparticles (NPs) and environmentally friendly ('green') chitosan. The polymer (chitosan) not only acted as the reducing agent for the metal ions, but also stabilized the product NPs by anchoring them. The majority of the particles produced in this way had sizes less than 5 nm. The catalytic activity of the composite was investigated photometrically by monitoring the reduction of 4-nitrophenol (4NP) in the presence of excess NaBH4 in water, under both heterogeneous and micro-heterogeneous conditions. The reaction was first order with respect to the concentration of 4NP. We also observed that the apparent rate constant, kapp, for the reaction was linearly dependent on the amount of Ag NPs present in the composite. Moreover, the turn-over frequency (TOF) of the catalyst was found to be (1.5 ± 0.3) × 10−3 s−1, when the reaction was carried out under heterogeneous conditions. The Ag NPs in the composite retained their catalytic activities even after using them for ten cycles. Our observations also suggest that the catalytic efficiency under micro-heterogeneous conditions is much higher than under heterogeneous conditions. Thus the composite we have represents an ideal case of an environmentally friendly and stable catalyst, which works under heterogeneous as well as micro-heterogeneous conditions with the advantage of nanoscopic particles as the catalyst.read more
Citations
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Bio-nanocomposites for food packaging applications
TL;DR: The most promising nanoscale fillers are layered silicate nanoclays such as montmorillonite and kaolinite as mentioned in this paper, which can provide active and/or smart properties to food packaging systems.
Journal ArticleDOI
Functional Characterization of Chitin and Chitosan
Inmaculada Aranaz,Marian Mengíbar,Ruth Harris,Ines Panos,Beatriz Miralles,Niuris Acosta,Gemma Galed,Angeles Heras +7 more
TL;DR: A functional characterization of chitin and chitosan regarding some biological properties and some specific applications (drug delivery, tissue engineering, functional food, food preservative, biocatalyst immobilization, wastewater treatment, molecular imprinting and metal nanocomposites) is presented.
Journal ArticleDOI
Photochemical green synthesis of calcium-alginate-stabilized Ag and Au nanoparticles and their catalytic application to 4-nitrophenol reduction.
TL;DR: The as-prepared new solid-phase biopolymer-based catalysts are very efficient, stable, easy to prepare, eco-friendly, and cost-effective, and they have the potential for industrial applications.
Journal ArticleDOI
In situ assembly of well-dispersed Ag nanoparticles (AgNPs) on electrospun carbon nanofibers (CNFs) for catalytic reduction of 4-nitrophenol
TL;DR: It was suggested that the CNFs/AgNPs composite nanofibers exhibited high catalytic activity in the reduction of 4-NP, which might be attributed to the high surface areas of AgNPs and synergistic effect on delivery of electrons between C NFs and Ag NPs.
Journal ArticleDOI
Polymer-supported metals and metal oxide nanoparticles: synthesis, characterization, and applications
TL;DR: In this article, the authors present a broad coverage of nanoparticles and polymeric/biopolymeric host materials and the resulting properties of the hybrid composites, and discuss the role of the Donnan membrane effect exerted by the host functionalized polymer in harnessing the desirable properties of metal and metal oxide nanoparticles for intended applications.
References
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Journal ArticleDOI
A class of non-precious metal composite catalysts for fuel cells
Rajesh Bashyam,Piotr Zelenay +1 more
TL;DR: The results of this study show that heteroatomic polymers can be used not only to stabilize the non-precious metal in the acidic environment of the PEFC cathode but also to generate active sites for oxygen reduction reaction.
Journal ArticleDOI
Oral gene delivery with chitosan--DNA nanoparticles generates immunologic protection in a murine model of peanut allergy.
TL;DR: It is demonstrated that oral allergen-gene immunization with chitosan–DNA nanoparticles is effective in modulating murine anaphylactic responses, and its prophylactic utility in treating food allergy is indicated.
Journal ArticleDOI
Silver nanoparticle catalyzed reduction of aromatic nitro compounds
TL;DR: In this article, the plasmon band of the silver metal nanoparticles formed in situ are the active catalyst for reducing aromatic nitro compounds to amines in aqueous medium.
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Thermosensitive core--shell particles as carriers for Ag nanoparticles : modulating the catalytic activity by a phase transition in networks
TL;DR: It is demonstrated that thermosensitive core–shell networks may indeed be used as such a nanoreactor by modulating the activity of nanoparticles through a thermodynamic transition that takes place within the carrier system.
Journal ArticleDOI
Biofabrication with chitosan.
Hyunmin Yi,Li-Qun Wu,William E. Bentley,Reza Ghodssi,Gary W. Rubloff,James N. Culver,Gregory F. Payne +6 more
TL;DR: The traditional motivation for integrating biological components into microfabricated devices has been to create biosensors that meld the molecular recognition capabilities of biology with the signal processing capabilities of electronic devices, but a different motivation is emerging; biological components are being explored to radically change how fabrication is achieved at the micro- and nanoscales.