Electrochemical synthesis of metal–polypyrrole composites and their activation for electrocatalytic reduction of oxygen by thermal treatment

High‐lateral resolution X‐ray fluorescence microspectroscopy and dynamic mathematical modelling as tools for the study of electrodeposited electrocatalysts

“…1(A)] agrees with the typical curves reported in the literature for conducting polymers. [5,11] Electropolymerisation starts at potentials higher than 0.9 V on the polymer-free GC surface (first cycle), while a lower overpotential is necessary when PPy is present at the electrode surface (successive cycles). The two broad waves appearing at~0 ÷ 0.4 V during the positive-going scan and at~À0 ÷ À0.2 V during the cathodic scan correspond respectively to the doping-undoping processes of the PPy film with perchlorate anions.…”

“…, as recommended by Schilling et al [11] The counter electrode was cleaned by immersion in concentrated HNO 3 to remove the metal and by annealing in a butane flame to eliminate organic residues.…”

Coelectrodeposition of Ternary Mn-Oxide/Polypyrrole Composites for ORR Electrocatalysts: A Study Based on Micro-X-ray Absorption Spectroscopy and X-ray Fluorescence Mapping

“…Of course the ORR efficiency depends not only on the nature of the metals, but it is a system property [58]. Since as-formed PPy is ORR inactive [37], the knowledge of the metal chemical state inside the polymeric matrix and its correlation with the electrodeposition parameters is key to optimising the synthesis process towards more efficient electrocatalysts.…”

“…The electrodeposition protocol was a modification of the step pulsed potential method originally proposed in [37] and revised in [15,44], consisting in an initial step at 0 V for 1 s (#1), a subsequent anodic pulse at +1.2 V for 0.5 s (#2), a cathodic step at −1.8 V for 0.5 s (#3) and a final anodic step at +1.2 V for 0.2 s (#4). The potential values have been selected according to the approach discussed in [40,41].…”

“…This approach is not strictly CECD in the sense defined above, but it is closely related to it in that a single bath containing both pyrrole and a metal salt was employed. (ii) Reactive metals-(ii.a) Co/PPy: the synthesis from a single Co-pyrrole bath by two-step anodic-cathodic polarization is reported in [32]; CECD from an acetonitrile bath for the fabrication of ORR electrocatalysis is expounded in [36]; in [37] the same system has been studied by applying a complex anodic-cathodic pulse sequence: this work is chiefly focused on Co/PPy composites, but some results are also reported on Mn/PPy and Fe/PPy; (ii.b) PPy/SO4-Cu [35] CECD has also been regarded as an improvement of two-step processes, able to yield finer dispersions of Cu without pore-clogging. (ii.c) Fe/PPy: grown by potentiostatic RPP has been shown to allow the combination of the peculiar magnetic properties of matrix and dispersoid [38].…”