Optimization and characterization of nanostructured paper-based electrodes

Abstract

Paper-based working electrodes were modified by the addition of nanomaterials (carbon nanofibers, gold nanoparticles, graphene and hybrids of them), with the aim to increase the conductivity and to obtain an electroactive platform with improved analytical behaviour. The effect of the nanostructures was evaluated by using cyclic voltammetry and dopamine as electrochemical probe. The modifications with in-situ generated nanomaterials such as gold nanoparticles (AuNPs) or others requiring treatment like graphene oxide (GO), were optimized by factorial design. The characterization of the cellulose based electrodes by scanning electron microscopy (SEM) showed the distribution of carbon nanofibers and the presence of AuNPs around the cellulose fibers. The partial modification made by the carbon ink was also monitored by attenuated total reflection (ATR) spectrometry. Electrodes modified with rGO and AuNPs exhibited higher intensity peaks with more reversibility and reproducibility than unmodified paper. The highest intensities and lowest limits of detection were achieved with paper electrodes modified with hybrid nanostructures composed by both CNFs and AuNPs.

Paper-based electrochemical transducer modified with nanomaterials for mercury determination in environmental waters

“…Following a procedure previously developed in our group [34,38], the working electrode (WE) of the screen-printed platform as well as the ceramic surface that is located between the WE and auxiliary (AE) and reference (RE) electrodes, were covered by the cellulosic electrode. Every paper electrode was cut to obtain a circle with an area of 4 mm 2 as shown in Figure 1.…”

Paper-Based Working Electrodes Coated with Mercury or Bismuth Films for Heavy Metals Determination

“…It is composed of cellulose fibers which confer properties like roughness and hydrophilicity, becoming easy to handle, with the possibility to form three-dimensional sensors [40][41][42][43]. Paper can also be modified by the addition of (i) hydrophobic materials, like wax, to form barriers that allow customization of the electrochemical cell, (ii) appropriate inks to have a conductive surface or (iii) nanostructures to improve selectivity and/or sensitivity [56][57][58][59][60]. Research literature on the determination of heavy metals by using paper electrodes is scarce.…”

“…In this work, we studied the ex situ deposition of bismuth films on a working paper-based electrode developed in previous works [59,64,65] and compared the performance with that obtained with more traditional mercury films.…”

Predictive Modelling to Study the Electrochemical Behaviour of PdO, TiO2 and Perovskite-Type LaFeO3 Modified Carbon Paste Electrodes

“…The study of electrode features provides valuable information concerning the electrochemical features of these devices. In this context, modifications are usually studied by methods such as voltammetry and impedimetry [7,8]. Regarding the theoretical circuit design of an electrode, Electrochemical Impedance Spectroscopy (EIS) provides deep information on phase shifts and charge kinetics, henceforth turning this method into an optimal alternative to characterize the electrochemical features of many modifications [9,10].…”