Shape-dependent electrocatalytic activity of free gold nanoparticles toward glucose oxidation

Abstract

The synthesis of shape and size-controlled free gold nanoparticles (AuNPs) was achieved by wet chemical methods. The UV-vis spectroscopy measurements and transmission electron microscopy characterizations confirmed the fine distribution in size and shape of the AuNPs. The zeta potential measurements permitted the evaluation of the stability of the AuNPs suspension. For the first time, the shape dependence on the electrocatalytic activity of these NPs is thoroughly investigated. The underpotential deposition (UPD) of lead reveals that their crystallographic facets are affected by their shape and growth process. Moreover, the glucose oxidation reaction strongly depends on the shape of AuNPs. Indeed, the gold nanocuboids (GNCs) and the spherical gold nanoparticles (GNSs) are significantly more active than the gold nanorods (GNRs) followed by the polyhedrons (GNPs). The oxidation process occurs at low potential for GNCs whereas the current densities are slightly higher for GNSs electrodes. Most importantly, the control of the shape and structure of nanomaterials is of high technological interest because of the strong correlation between these parameters and their optical, electrical and electrocatalytic properties.

Nanostructured Inorganic Materials at Work in Electrochemical Sensing and Biofuel Cells

“…These fundamental works highlight two distinguished effects: the crystallographic structure for Au(hkl) and the electronic interaction between silver and gold atoms. Recent experimental data confirmed the cornerstone role of the crystallographic structure of AuNPs on the reactivity of glucose [71][72][73][74]. For low indexes, the reactivity of glucose over Au(hkl) surfaces increases in the order (111) < (110) < (100).…”

The Effect of Electrodeposition Parameters and Morphology on the Performance of Au Nanostructures for the Detection of As (III)

“…Pb UPD is an effective technique to probe the surface crystallographic structures of gold materials and has been extensively studied on polycrystalline and single crystalline gold materials. [48][49][50] Since the lead UPD process is stucture sensitive, the potentials of the lead deposition and stripping peaks are used to assist with identification of the relative energy of facets on the surface of the gold spikes in contact with solution. 40,51 Figure S4 (see Supporting Information) depicts the cyclic voltammograms of the gold spikes in an alkaline solution of lead (II) nitrate with a broad potential window.…”

Electrochemical Reactivity at Free and Supported Gold Nanocatalysts Surface

“…This behavior of the gold electrode in the double layer region as well as the surface oxidation region is structure dependent as evidenced by Kokoh et al [3,4] on size and shape controlled gold nanoparticles and Hamelin [52] on gold single-crystal Au (1 1 1) and Au (1 0 0). At higher potentials than 1.2 V vs. RHE, different oxidation peaks depending on the particles shape can be noticed: one oxidation peak is observed for spherical gold nanoparticles at 1.25 V vs. RHE ( Figure 5A); two peaks are revealed on the surface of AuNRs and polyhedral particles at 1.25 V and 1.35 V vs. RHE, respectively (Figure 5B), and one main oxidation peak is observed at 1.25 V followed by shoulder peaks between 1.35 V and 1.50 V vs. RHE for bulk gold electrode.…”

“…In addition, spherical AuNPs can also be synthesized by the reduction in gold salts by sodium borohydride in the presence of CTAB as surfactant [3][4][5]. After the appropriated time and amount of chemicals as reported, AuNPs with different sizes can be obtained in particular AuNSs-6 and AuNSs-14 samples, respectively.…”

“…It is well known that acac is a good organic diketone chelate ligand [37]. In the presence of gold salt HAuCl 4 , it can complex to form a stable chelate Au(III)-acac which can decompose under ambient conditions to form spherical nanoparticles of variable size (10-40 nm). The kinetics of the reduction depends on the pH value.…”