Mn Oxide‐Silver Composite Nanowires for Improved Thermal Stability, SERS and Electrical Conductivity. Issue 29 (30th May 2014)

• Record Type: Journal Article
• Authors: Pradhan, Mukul; Sinha, Arun Kumar; Pal, Tarasankar
• Is Part Of: Chemistry. Volume 20:Issue 29(2014)
• Page Start: 9111
• Page End: 9119
• Publication Date: 2014-05-30
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201304518
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Redox transformation reaction between aqueous AgNO<sub>3</sub> and Mn(CH<sub>3</sub>COO)<sub>2</sub> at low temperature (∼80 °C) has been adopted for industrial‐scale production of uniform Ag–MnOOH composite nanowires for the first time. Varying amounts of incorporated Ag in the composite retain the 1D morphology of the composite. Nanowires upon annealing evolve Ag–MnO<sub>2</sub> nanocomposites, once again with the retention of the parental morphology. Just 4 % of silver incorporation in the composite demonstrates metal‐like conducting performance from the corresponding semiconducting material. Transition of MnO<sub>2</sub> to Mn<sub>2</sub>O<sub>3</sub> to Mn<sub>3</sub>O<sub>4</sub> takes place upon heat treatment in relation to successive increase in Ag concentrations in the nanowires. The composites offer resistance to the observed oxide transformation. This is evidenced from the progressive increase in transition temperature. In situ Raman, ex situ thermal and XRD analysis corroborate the fact. The composite with 12 % Ag offers resistance to the transformation of MnO<sub>2</sub>, which is also verified from laser heating. Importantly, Ag nanoparticle incorporation is proved to offer a thermally stable and better surface enhanced Raman scattering (SERS) platform than the individual components. Both the Ag–MnOOH and Ag–MnO<sub>2</sub> nanocomposites with 8 atomic % Ag show the best SERS enhancement (enhancement factor ∼10<sup>10</sup>). The observed enhancement relates to charge transfer as well as electromagnetic effects.</p> </abstract>