Electrocatalytic activity for hydrogen evolution of polypyrrole films modified with noble metal particles

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

“…As far as nanocomposites are concerned, electrodeposition can give rise either to the direct deposition of the metal particles onto the growing polymer layer [17] or to the entrapment of metal complexes that yield metal particles during a subsequent reduction step. [18] The composite morphology and metal distribution are affected in a complex way by a wide range of electrodeposition parameters, such as the electronic conductivity of PPy, doping degree, polymer porosity, metal ion transport within the PPy network structure, chemical interactions between metal ions and their complexes with the polymer, direct metal electroplating onto the polymer. Moreover, the competition between the metal ion reduction processes going on on the surface or inside the polymer layer and on the underlying metal surface, potentially accessible through the pinholes of the polymer film, notably affects the composite structure.…”

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

“…In this work, we shall concentrate on the first approach-that for simplicity we shall denominate coelectrodeposition (CECD), giving rise either to the direct deposition of the metal particles onto the growing polymer layer (a typical example is e.g., [3]) or to the entrapment of-typically anionic, (exclusively anionic in the case of pure PPy)-metal complexes that yield metal particles during a subsequent reduction step (e.g., [4]). It has been recently demonstrated that suitable co-polymers of PPy, such as PPy-PSS (Polystyrene sulphonate), can capture cations [5].…”

“…In this section we omit details on classical morphological (SEM, TEM), structural (XRD, SAED) and electrochemical (CV, LSV, chronocoulometry) methods as well as on dedicated functional characterizations and rather concentrate on methods that have been chosen specifically for the study of the intrinsic properties of pure PPy films and PPy-matrix composites. (i) AES with depth profiling for the assessment of particle localization within the CP matrix [18]; (ii) AFM for the quantification of homogeneity, grain size and surface roughness (in situ Au/PPy [19]); (iii) DTA and TGA for thermal stability analyses [20]; (iv) EPR for studies of polaronic conduction mechanisms [21] and electronic interactions bewteen PPy matrix and oxide dispersoids [22]; (v) EQCM for the in situ monitoring of electropolymerization and composite electrodeposition processes [23] and for the study of ion fluxes into and out of electropolymerized films [5,24,25]; (vi) ERS [26,27] and spectroellipsometry [28] for the definition of charge-transfer processes during both electropolymerization and electrocatalysis; (vii) FTIR and Raman, for the investigation of the interaction between PPy matrix and oxide particles (FTIR Fe2O3 [20], FTIR TiO2 [29], FTIR Fe-Co/PPy [30], ATR-IR Cu basic salts [5], Raman Fe3O4 [31], Raman SnO2 [2]); (viii) ICP-AES for the analysis of the metal content in PPy-matrix composites (Sn [2]); (ix) NEXAFS [32] for a detailed study of charge transfer between Co and PPy; (x) Solid state electrochemical impedance for the differential evaluation of the electrical resistance of films [31]; (xi) UV spectroscopy was used for the study of the electronic structure of PPy and of the way the presence of particles modifies it [33]; (xii) XPS with depth profiling revealed the chemical state of inorganic dispersoid (Fe in prussian blue/PPy CECD [34], Sn in SnO2/PPy [10], Cu and S in Cux(OH)y(SO4)z [5], Cu and N in SO4-Cu/PPy [35], Pt and Ru [4]) and allowed the assessment of the chemical interaction of the dispersoid with the matrix (chiefly by N 1s spectroscopy …”

“…(i.b) Pt/PPy: sandwich composites, consisting of multiple electrodeposited PPy and Pt layers have been studied in [17]. (i.c) The growth of Ir, Pd, Pt and Ru/PPy composites has been described in [4], as obtained by polymerization in the presence of anionic Pt-group complexes that were reduced in a post-treatment, applied after completion of the polymer growth phase. 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.…”

Electrodeposition of Polypyrrol/Platinum Films

“…Los sustratos de acero inoxidable, utilizados como soporte en sistemas poliméricos modificados con partículas catalíticas, son muy atractivos para las aplicaciones tecnológicas. Considerando que es un material económico y además, que el acero inoxidable puede sufrir una modificación interfacial con la formación de una película delgada de óxidos que conducen a una pasivación del mismo [29,30]. En este trabajo se presenta la obtención electroquímica de películas de PPy y PPy/Pt depositadas sobre acero inoxidable 304, las cuales se caracterizaron por medio de espectroscopia Raman, microscopía electrónica de barrido, perfilometría, impedancia y se evaluaron sus potenciales de oxidación por voltametría cíclica.…”