A Multiple Evaluation Approach of Commercially Available Screen‐Printed Nanostructured Carbon Electrodes

Abstract

Commercially available carbon‐based screen‐printed electrodes were studied by cyclic voltammetry and electrochemical impedance spectroscopy in their behavior towards electron transfer to the soluble fast redox probes hexacyanoferrate(III), hexaammineruthenium(III) and methyl‐viologen. Semi‐infinite linear diffusion was observed for hexacyanoferrate(III) probe, with heterogeneous electron transfer rate constants significantly favored on nanotubes‐modified surfaces. Finite diffusion was observed for methyl‐viologen on graphene electrodes, which was reflected in the enhancement of the faradic currents by 4‐folds. Hexaammineruthenium(III) showed mixed diffusion behavior. These characteristics are reflected in the voltammetric behavior of lead(II) and cadmium(II) stripping from in‐situ deposited bismuth layer.

Limited Diffusion and Cell Dimensions in a Micrometer Layer of Solution: An Electrochemical Impedance Spectroscopy Study

“…where R is the gas constant, T the absolute temperature, A the electrode geometric area, F the Faraday constant, and C * the bulk concentration of the electroactive species. The rate constant values under thin‐layer conditions is of the same order to those reported for the same electrochemical system under semi‐infinite linear diffusion, . Again, a sigmoidal behavior relates the heterogeneous rate values with the coverslip weight (Figure ).…”

“…The exponent value of the Warburg diffusion impedance is P W~0 .5, in agreement with the semi-infinite linear nature of the diffusion close to the electrode surface. The negligible difference from the theoretical value of 0.5 (less than 5%) is ascribed to some surface roughness, as expected for screen-printed electrodes, which cannot be polished [13] .…”

“…[12] The experimental set-up simply consisted in the smash of a microdrop of solution onto the screen-printed electrodic system by a coverslip, yielding a thin-layer voltammetric output that extends, from an analytical point of view, the use of screen-printed electrodes (SPEs) in decentralized analyses. [13][14][15] Under these experimental conditions, electro-chemical impedance spectroscopy (EIS) in the frequency-range above 30 Hz unequivocally proved that electroactive species moved in a limited diffusion regime, discarding any surface adsorption process. This short frequency-range only assessed a distance from the electrode surface of ca.…”

“…Recently, we presented a novel and simple approach to produce a thin ‐ layer of electrolyte over a whole screen‐printed electrodic system, taking advantage of the geometric distribution of the working, reference and counter electrodes on a same plane . The experimental set‐up simply consisted in the smash of a microdrop of solution onto the screen‐printed electrodic system by a coverslip, yielding a thin‐layer voltammetric output that extends, from an analytical point of view, the use of screen‐printed electrodes (SPEs) in decentralized analyses . Under these experimental conditions, electrochemical impedance spectroscopy (EIS) in the frequency‐range above 30 Hz unequivocally proved that electroactive species moved in a limited diffusion regime, discarding any surface adsorption process.…”

Carbon Nanofiber and Meldola Blue Based Electrochemical Sensor for NADH: Application to the Detection of Benzaldehyde

“…The electroactive area of CNF‐modified electrodes was 0.079±0.012 cm 2 (n=5 electrodes), around 41 % higher than the area of bare graphite electrodes, which was calculated as 0.056±0.006 cm 2 . Various values of the electrochemically active area within the range 0.07–0.11 cm 2 were reported in the literature for the bare DRP‐110 . The lower active area compared to the geometric area of 0.126 cm 2 is explained by the electrochemically inactive binders included in the screen‐printing ink.…”