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Title: Nanoscale Au-In alloy-oxide core-shell particles as electrocatalysts for efficient hydroquinone detection

The presence of hydroquinone (HQ), a phenol ubiquitous in nature and widely used in industry, needs to be monitored because of its toxicity to the environment. Here we demonstrate efficient detection of HQ using simple, fast, and noninvasive electrochemical measurements on indium tin oxide (ITO) electrodes modified with nanoparticles comprising bimetallic Au–In cores and mixed Au–In oxide shells. Whereas bare ITO electrodes show very low activity for the detection of HQ, their modification with Au–In core–shell nanoparticles induces a pronounced shift of the oxidation peak to lower potentials, i.e., facilitated oxidation. The response of the different electrodes was correlated with the initial composition of the bimetallic nanoparticle cores, which in turn determined the amount of Au and In stabilized on the surface of the amorphous Au–In oxide shells available for the electrochemical reaction. While adding core–shell nanostructures with different compositions of the alloy core facilitates the electrocatalytic (reduction-) oxidation of HQ, the activity is highest for particles with AuIn cores (i.e., a Au:In ratio of 1). This optimal system is found to follow a single pathway, the two-electron oxidation of the quinone–hydroquinone couple, which gives rise to high oxidation peaks and is most effective in facilitating the electrode-to-analyte charge transfermore » and thus detection. The limits of detection (LOD) decreased when increasing the amount of Au exposed on the surface of the amorphous Au–In oxide shells. As a result the LODs were in the range of 10–5 – 10–6 M and were lower than those obtained using bulk Au.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [1]
  1. Univ. of Nebraska-Lincoln, Lincoln, NE (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Univ. de Valladolid, Valladolid (Spain); Brookhaven National Lab. (BNL), Upton, NY (United States)
  4. Univ. de Valladolid, Valladolid (Spain)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1932-7447; R&D Project: 16082; KC0403020
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 119; Journal Issue: 44; Journal ID: ISSN 1932-7447
American Chemical Society
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES amorphous mixed gold-indium oxide; alloy nanoparticles; electrochemical catalysts; transmission electron microscopy