Altered electrochemistry of poly(3,4-ethylenedioxythiophene) after activation of the inserted cobalt ions

Cobalt ions were inserted into poly(3,4-ethylenedioxythiophene) by cyclic voltammetry in a 0.1M Co(NO3)2 aqueous solution (PEDOT(Co)). After activation of the inserted cobalt, the PEDOT(aCo) system was investigated by cyclic voltammetry, digital video electrochemistry, spectroelectrogravimetry, and coupled impedance techniques (ac-electrogravimetry) to elucidate the key role of inserted cobalt ions in the altered electrochemistry of PEDOT. The incorporation of Co2+ involves slow transfer of cations for charge compensation during 2+⇄3+ conversion inside the PEDOT. This fact explains the enhanced charge storage showed by PEDOT(aCo) compared with pristine PEDOT at similar potentials. Finally, the stability of PEDOT(aCo) was investigated by cyclic voltammetry measuring at the same time current, mass and motional resistance variation during 100 cycles offering high stability at all times.This work was supported by the Spanish E3TECH-PLUS Research Network RED2022-134552-T (MICINN/AEI, Spain). SEM was carried out in the Microscopy Section of Central Service for Experimental Research (SCSIE) of the University of Valencia. Esteban Guillén acknowledges the support from the Generalitat Valenciana (INVEST/2022/431)

A statistical interpretation of the voltammetry of adsorbed substances under the perspective view of the Digital Video Electrochemistry

Coupling cyclic voltammetry with digital video electrochemistry allows identifying different electrochemical processes overlapped. Mathematical description of the time evolution of mean color intensities and their standard deviation at the studied electrode surface during voltammetric experiments were developed. Parallel electrochemical reactions and the presence of colored intermediate species was also evaluated. Single expressions for the shape of these curves, including the maximum of peaks or the half-peak widths are analyzed on the basis of a single layer covered electrode. The good similitude among current, mean color intensities derivative and variance curves allows a statistical interpretation for these processes

Reconocimiento del alumnado como personas investigadoras

En este trabajo se pretende mostrar ejemplos de actividades experimentales que contribuyan al Reconocimiento del Alumnado como personas investigadoras. En las experiencias docentes se ha utilizado tecnologías de bajo costo para la adquisición de imágenes [1] en entornos académicos de distintos niveles, desde preuniversitarios a postgrado. Actualmente, los smartphones y las tablets son herramientas muy potentes al alcance de los alumnos para observar fenómenos, realizar actividades grupales y acceder a las bases de datos. Incluso, como herramientas para aprovechar la realidad virtual y la inteligencia artificial. Sin embargo, para su uso eficaz en docencia, es necesario que haya una relación profesorado/alumnado tal y como Axel Honneth entiende el Reconocimiento entre persona

Measurement of total antioxidant capacity by electrogenerated iodine at disposable screen printed electrodes

Total antioxidant capacity is an important parameter for the evaluation of the oxidative status in different kinds of biological samples such as plant extracts, or in food industry. We report a fast, easy, portable, cost-effective electroanalytical method to measure total antioxidant capacity, based on the reaction of natural antioxidants with electrogenerated iodine using disposable platinum screen-printed electrodes. This reaction can be measured by the increment of the electrochemical current signal of iodide oxidation to iodine during a voltammetric cycle. Iodine reacts with reducing compounds such as glutathione, ascorbate, gallic acid and NADH without interference of the corresponding oxidized counter-parts. The addition of ascorbate oxidase also allows the concentration of ascorbate to be determined. The method was tested with real samples of plant extracts and the results correlated well with those obtained with a standard spectrophotometric method