Ver PDF

Cobalt oxide (Co3O4) and copper-doped cobalt oxide (CuxCo3-xO4) films supported on titanium have been prepared by the thermal decomposition method. The electrodes have been characterized by different techniques like scanning Electron Microscopy (SEM), cyclic voltammetry (CV), and X-Ray photoelectron spectroscopy (XPS). The XPS spectra correspond to a characteristic monophasic Cu-Co spinel oxides when x is below 1. However, when the copper content exceeds that for the stoichiometric CuCo2O4 spinel, a new CuOphase segregates at the surface. The analysis of the surface cation distribution in spinel structure indicates that Cu(II) cation are preferently located in octahedral sites of higher electrochemical activity.

Calderon would like to express her thanks to the Fondecyt project number 167-2015 (Concytec, Perú). Pujada express his thanks to the project number FC-F-3-2017, Vicerrectorado de Investigación (UNIPerú), and also to the Universidad de Chile and the Fondecyt Project 1110148 (Conicyt, Chile).

In this study, a new electrochemical sensor for determination of cyanide is proposed. The sensor is formed by a carbon paste electrode modified with hierarchical porous carbon and silver sulfide nanoparticles. The morphology characterization was performed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), while the chemical and electrochemistry characterization were performed by energy dispersive X-ray spectroscopy and cyclic voltammetry, respectively. Under the optimized conditions, the Ag2SNPs-HPC300 sensor presented a large concentration linear range of 5.9 × 10−7 to 1.1 × 10-3 mol L-1, and limit of detection of 7.0 × 10-8 mol L-1 using square-wave adsorptive anodic stripping voltammetry (SWAdASV) technique. The analytical response of the Ag2SNPs-HPC300 sensor was evaluated in presence of different compounds, and the results showed a RSD of 4.3% in ...