Low-Noble-Metal-Loading Hybrid Catalytic System for Oxygen Reduction Utilizing Reduced-Graphene-Oxide-Supported Platinum Aligned with Carbon-Nanotube-Supported Iridium

Catalysts

Enrico Negro¹  Vito Di Noto¹  Leszek Stobinski²  Artur Malolepszy²  Agnieszka Zlotorowicz³  Magdalena Modzelewska³  Jerzy Zak³  PawelJ. Kulesza³  Beata Dembinska³  Krzysztof Miecznikowski³  IwonaA. Rutkowska³  Maciej Krzywiecki⁴ 

[1]Department of Industrial Engineering, Università degli Studi di Padova in Department of Chemical Sciences, Via Marzolo 1, 35131 Padova (PD), Italy

[2]Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warynskiego 1, PL-00-645 Warsaw, Poland

[3]Faculty of Chemistry, University of Warsaw, Pasteura 1, PL-02-093 Warsaw, Poland

[4]Institute of Physics–CSE, Silesian University of Technology, Konarskiego 22B, PL-44-100 Gliwice, Poland

关键词: reduced graphene oxide;    carbon nanotubes;    platinum catalyst;    iridium additive;    oxygen reduction reaction;    hydrogen peroxide intermediate;   

DOI  :  10.3390/catal10060689

来源: DOAJ

【 摘 要 】

Hybrid systems composed of the reduced graphene oxide-supported platinum and multiwalled carbon nanotube-supported iridium (both noble metals utilized at low loadings on the level of 15 and ≤2 µg cm⁻², respectively) were considered as catalytic materials for the reduction of oxygen in acid media (0.5-mol dm⁻³ H₂SO₄). The electrocatalytic activity toward reduction of oxygen and formation of hydrogen peroxide intermediate are tested using rotating ring–disk electrode (RRDE) voltammetric experiments. The efficiency of the proposed catalytic systems was also addressed by performing galvanodynamic measurements with gas diffusion electrode (GDE) half-cell at 80 °C. The role of carbon nanotubes is to improve charge distribution at the electrocatalytic interface and facilitate the transport of oxygen and electrolyte in the catalytic systems by lowering the extent of reduced graphene oxide restacking during solvent evaporation. The diagnostic electrochemical experiments revealed that—in iridium-containing systems—not only higher disk currents, but also somehow smaller ring currents are produced (when compared to the Ir-free reduced graphene oxide-supported platinum), clearly implying formation of lower amounts of the undesirable hydrogen peroxide intermediate. The enhancement effect originating from the addition of traces of iridium (supported onto carbon nanotubes) to platinum, utilized at low loading, may originate from high ability of iridium to induce decomposition of the undesirable hydrogen peroxide intermediate.

【 授权许可】

Unknown