Size‐Dependent Electrocatalytic Activity of Free Gold Nanoparticles for the Glucose Oxidation Reaction. Issue 10 (11th March 2016)

• Record Type: Journal Article
• Authors: Hebié, Seydou; Napporn, Teko W.; Morais, Cláudia; Kokoh, K. Boniface
• Is Part Of: Chemphyschem. Volume 17:Issue 10(2016)
• Page Start: 1454
• Page End: 1462
• Publication Date: 2016-03-11
• Subjects: electrocatalysis -- glucose -- gold -- nanoparticles -- oxidation; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201600065
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: Understanding the fundamental relationship between the size and the structure of electrode materials is essential to design catalysts and enhance their activity. Therefore, spherical gold nanoparticles (GNSs) with a mean diameter from 4 to 15 nm were synthesized. UV/Vis spectroscopy, transmission electron microscopy, and under‐potential deposition of lead (UPDPb ) were used to determine the morphology, size, and surface crystallographic structure of the GNSs. The UPDPb revealed that their crystallographic facets are affected by their size and the growth process. The catalytic properties of these GNSs toward glucose electrooxidation were studied by cyclic voltammetry, taking into account the scan rate and temperature effects. The results clearly show the size‐dependent electrocatalytic activity for glucose oxidation reactions that are controlled by diffusion. Small GNSs with an average size of 4.2 nm exhibited high catalytic activity. This drastic increase in activity results from the high specific area and reactivity of the surface electrons induced by their small size. The reaction mechanism was investigated by in situ Fourier transform infrared reflectance spectroscopy. Gluconolactone and gluconate were identified as the intermediate and the final reaction product, respectively, of the glucose electrooxidation. Abstract : Size matters ! The crucial role of the size and surface crystallographic structure of gold nanocatalysts is demonstrated for the electrooxidation of glucose in alkaline media. The electrocatalytic activity of the gold nanoparticles increases reciprocally with the particle size. By using a combination of in situ infrared spectroscopy and electrochemistry techniques, it is shown that δ‐gluconolactone and gluconate are the intermediate species and the main reaction product, respectively.