The size effect of Pt nanoparticles: a new route to improve sensitivity in electrochemical detection of As(iii)

Abstract

In this work, we demonstrate a size-dependent effect of Pt nanoparticles ranging 2–5 nm on the electrochemical behavior toward arsenic [As(III)]. This work presents the stripping voltammetry for sensitive identification of As(III) using four types of platinum nanoparticles for the first time, the sizes of which are 2.3, 3.5, 4.3 and 5.5 nm. Anodic oxygen-transfer reactions are expected to explain the interaction between As(III) and different size Pt nanoparticles for scientific understanding of the size effect on stripping voltammetry. We report that surface sites of Pt are made up of {111}, {100} facts and the edges. The percentage of the edges decreases with the increase of the particle size, while the percentage of {111}, {100} sites increases. The binding energy of the edge sites is higher than that of {111}, {100} facts. As a result, the desorption of the intermediates during the electrochemical process is easier on the edge sites. Therefore, the sensitivity of detection of As(III) is higher on the edge sites than on the {111} and {100} sites.