Highly Ordered Macroporous Poly-3,4-ortho-xylendioxythiophene Electrodes as a Sensitive Analytical Tool for Heavy Metal Quantification

Abstract

Highly ordered macroporous electrodes of the conducting polymer poly-3,4-ortho-xylendioxythiophene (PXDOT) are presented as a sensitive analytical tool for heavy metal ion quantification due to a controlled gain in electroactive area. They were designed by using colloidal crystal templates. A direct correlation between the final number of porous layers and the deposition charge (Q d) employed for electropolymerization is observed. All the electrodes exhibit a surface-templated structure due to an interaction between the radical cation, formed during the electropolymerization, and the surface groups of the silica beads. The voltamperometric response of the macroporous PXDOT electrodes shows a rather fast electron transfer with ΔE p values between 70 mV and 110 mV. Square wave anodic stripping voltammetric (SWASV) analysis of Cu2+ as a representative heavy metal ion shows a linear response in the subppm range. As a model application, the efficient quantification of Cu2+ in a commercial mezcal sample is validated by the standard addition method and the results correlate adequately with the values obtained by atomic absorption spectroscopy.

Microstructures of Binary Oxides with an Inverse Opal Structure Used as Photoelectrodes for Water Splitting

“…The diameter of the SiO 2 spheres obtained depends on the reaction time, so the shorter the time, the smaller the diameter of the spheres obtained. Among the diameters that have been used for opal synthesis are: 440 nm [50], >500 nm [49], < 0.2 μm [48], 500 nm [51]. The SiO 2 particles settle by gravity for a period of 5 to 20 days on the surface to be used as a support, this allows the growth of the solid phase of the opals, and finally the sediment is dried [50].…”

Electrochemical and Spectroscopic (FTIR) Evidence of Conducting Polymer-Cu Ions Interaction

“…The latter has gained our attention due to its outstanding electrochemical, electrical, and optical stability, even in hydroalcoholic media [ 26 , 27 , 28 ]. Recently, the possible quantification of Cu 2+ through the use of modified electrodes with PXDOT was studied [ 29 ]. However, a better understanding of the possible interaction between the matrix of these π-conjugated polymers and heavy metal ions is still needed and is the focus of this contribution.…”

In Situ Spectroelectrochemical-Conductance Measurements as an Efficient Tool for the Evaluation of Charge Trapping in Conducting Polymers

“…Among the different spectroscopies coupled with electrochemistry, UV–vis is one of the most used techniques due to the simple correlation between the absorption changes and the simultaneous electrochemical measurements. This technique has been used to study not only single step electron-transfers, but also multistep redox reactions or the formation of mixed-valence intermediates. − In particular, in situ UV–vis–NIR spectroelectrochemistry has been widely employed to evaluate the electronic transitions involved in the charging/discharging process of π-conjugated polymers. − These materials have received increasing attention due to their possible use in sensing, − energy storage and conversion, and environmental remediation, as well as in bioelectronics, , and neuromorphic computing . Nevertheless, the type of charge carrier, e.g ., σ-dimers, π-dimers, polaron pair, and bipolaron, and the mechanisms of charge carrier transport, intrawire and interwire , remains still a point of discussion. , Thus, an important aspect in conducting polymer (CP) research is to develop in situ spectroelectrochemical methods that allow real-time monitoring of the electrochemical, electric, and optical properties of conducting materials.…”