Insight on the Surface Structure Effect of Free Gold Nanorods on Glucose Electrooxidation

The physicochemical properties of noble metal such as gold strongly depend on their size, shape, and their surface structure composition. Gold NPs have been studied in electrocatalysis due to their unexpected activity toward the oxidation of organics. The chemical reactions studies on a well-defined shape provide fundamental data on the surface reactivity for understanding and designing novel catalytic materials. Therefore, different gold nanorods (GNRs) were synthesized by chemical growth process. The UV–vis spectroscopy and transmission electron microscopy measurements confirmed their well-defined shape and size distribution. Moreover, the under-potential of lead (UPD), which is a sensitive electrochemical surface characterization tool, has been used to assess GNRs crystallographic structure information. Additionally, the UPD of lead reveals that their crystallographic facets are affected by their growth process. Most importantly, the interaction between GNRs surface and the remaining capping agent (CTAB) adsorbed after cleaning process has a high effect on the lead deposition and also leads to a decrease in the electrochemical activity of GNRs. The activity of different GNRs toward glucose oxidation was also investigated. The correlation between the activity of these materials toward this reaction and their surface structure was established. It shows an enhancement of the electroactivity in the presence of (100) facets.