Improved catalytic activity and surface electro-kinetics of bimetallic Au–Ag core–shell nanocomposites. (29th October 2014)

• Record Type: Journal Article
• Authors: Monga, Anila; Pal, Bonamali
• Is Part Of: New journal of chemistry. Volume 39:Number 1(2015:Jan.)
• Page Start: 304
• Page End: 313
• Publication Date: 2014-10-29
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c4nj01419g
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : The Aucore –Agshell and hollow Ag–Au alloy nanostructures significantly improved (∼2 times) the reduction of 1, 3-dinitrobenzene relative to the monometallic ones demonstrating the role of the synergistic effect of the Au–Ag interface in catalytic activity. Abstract : This paper demonstrates the preparation of core–shell nanocomposites (NCs) of Aucore –Agshell (Au@Ag) and Agcore –Aushell (Ag@Au) for measuring their catalytic activity and electro-kinetic properties relative to their respective monometallic counterparts. A significant blue-shift (530 → 408 nm) and a red-shift (420 → 550 nm) of the surface plasmon band for Au@Ag and Ag@Au NCs, respectively, were observed due to increased size of binary composites depending on the nature of the core and shell material. The thickness of the deposited Ag shells varied from ∼3–10 nm on the Au core leading to the formation of Au@Ag NCs. On the other hand, the Ag core served as a sacrificial template, where Ag@Au NCs were converted to hollow Ag–Au alloy shells (∼15 nm) because of the galvanic reaction between them due to the difference in their redox potential. An increased zeta potential was found for resulting Au@Ag (+57.8 mV) and hollow Ag–Au alloy shell (−20.13 mV) NCs in comparison to monometallic Au (−6.13 mV) and Ag nanospheres (−5.74 mV) due to surface passivation with aqueous AgNO3 and AuCl4 − solution, respectively. These bimetallic NCs exhibited ∼2 times higher catalytic activity than the monometallic nanoparticles depending on the shell thickness and the core of the respective metals for the nitrobenzene and 1, 3-dinitrobenzene reduction.