Morphology of Gold Nanoparticles and Electrocatalysis of Glucose Oxidation
| Autor: | Sushma Karra, Marilyn Wooten, Wendell P. Griffith, Waldemar Gorski |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
General Chemical Engineering
Inorganic chemistry Oxide 02 engineering and technology Glassy carbon 010402 general chemistry 021001 nanoscience & nanotechnology Electrocatalyst 01 natural sciences Article Amperometry 0104 chemical sciences Catalysis chemistry.chemical_compound chemistry Colloidal gold Electrochemistry Gluconic acid 0210 nano-technology High-resolution transmission electron microscopy |
| Zdroj: | Electrochimica Acta. 218:8-14 |
| ISSN: | 0013-4686 |
| DOI: | 10.1016/j.electacta.2016.09.097 |
| Popis: | The shape-dependent activity of gold nanoparticles (AuNP) was studied by testing them as electrocatalysts for the notoriously slow non-enzymatic oxidation of glucose in neutral solutions. The AuNP of spherical and irregular (including polyhedral) morphologies were synthesized and attached to glassy carbon electrodes with chitosan. Voltammetric and mass spectrometric studies showed that the irregular AuNP were more catalytically active toward the oxidation of glucose to gluconic acid. No obvious differences between both morphologies were found based on their X-ray diffraction patterns and HRTEM images suggesting that the crystallographic orientation alone did not account for their catalytic properties. While both morphologies contain the (111) crystallographic planes that are catalytic toward glucose oxidation, the better activity of irregular AuNP was ascribed to a higher surface density of incipient gold oxide acting as a fast redox mediator for glucose oxidation. Supporting this, the AuNP of both morphologies oxidized glucose after their anodic activation, although not to the same extent. The amperometric (0.30 V) determination of glucose at electrodes made of irregular AuNP yielded a wide linear calibration plot (0.20–110 mM; R 2 , 0.998), sensitivity of 66 μA M −1 cm −2 , limit of detection of 100 μM (S/N, 3), and a response time below 5 s. The advantage of low-cost irregular AuNP over macro gold is that they are catalytic toward glucose oxidation without any need for prior activation. |
| Databáze: | OpenAIRE |
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