Platinum/polypyrrole-carbon electrocatalysts for direct borohydride-peroxide fuel cells

• Published in: Applied catalysis. B, Environmental Environmental, 2018-12, Vol.238, p.454-464
• Main Authors: Oliveira, Raisa C.P., Milikić, Jadranka, Daş, Elif, Yurtcan, Ayşe B., Santos, Diogo M.F., Šljukić, Biljana
• Format: Article
• Language: English
• Subjects: Anodes; Borohydride oxidation reaction; Borohydrides; Carbon; Catalysts; Cathodes; Charge exchange; Charge transfer; Chemical reduction; Direct borohydride fuel cell; Electrocatalysts; Fuel cells; Fuel technology; Hydrogen peroxide; Hydrogen peroxide reduction reaction; Mathematical analysis; Nanoparticles; Oxidation; Platinum; Polypyrrole-carbon composite; Polypyrroles; X ray photoelectron spectroscopy
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2018.06.057

[Display omitted] •Pt/PPy-C electrocatalysts with 5, 12, 20 and 35 wt.% of carbon were synthesized.•Pt/PPy-C were characterized by FTIR, Raman, XPS, SEM/EDS, TEM and ICP-MS.•Pt/PPy-C were tested as electrocatalysts for BH4− oxidation and H2O2 reduction.•Pt/PPy-C35% showed the best catalytic activity for both BOR and HPRR.•DBPFCs using Pt/PPy-C as anodes and/or as cathodes were assembled and tested. Polypyrrole-carbon (PPy-C) composites having different amounts of carbon (5–35 wt.%) decorated with platinum nanoparticles (Pt/PPy-C) were prepared and investigated for borohydride oxidation reaction (BOR) in alkaline medium and for hydrogen peroxide reduction reaction (HPRR) in acidic medium. Structural and morphological properties and composition of these electrocatalysts were determined by FTIR, Raman, XPS, SEM/EDS, TEM and ICP-MS analyses. Pt/PPy-C electrocatalysts were evaluated for BOR and HPRR by cyclic voltammetry and chronoamperometry. Faradaic and kinetic parameters, such as the number of exchanged electrons, n, charge transfer coefficient, α, apparent activation energy, Eaapp, and order of reaction, β, were calculated. n for BOR ranged from 6.0 to 7.6, while n for HPRR ranged from 1.0 to 2.0. Eaapp was found to range from 10 to 18 kJ mol−1 for BOR and from 8 to 14 kJ mol−1 for HPRR. The BOR was found to be a 1st order reaction with respect to BH4−. Pt/PPy-C35% electrocatalyst showed the best activity for both reactions. Fuel cell tests were done with Pt/PPy-C electrodes as anode, as cathode and as both anode and cathode in a direct borohydride-peroxide fuel cell (DBPFC). DBPFC with Pt/PPy-C35% as anode electrocatalyst gave the highest peak power density of 1432 W gPt−1 at current density of 2046 A gPt−1 and cell voltage of 0.70 V.