1. Low-Noble-Metal-Loading Hybrid Catalytic System for Oxygen Reduction Utilizing Reduced-Graphene-Oxide-Supported Platinum Aligned with Carbon-Nanotube-Supported Iridium
- Author
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Iwona A. Rutkowska, Agnieszka Zlotorowicz, Leszek Stobinski, Artur Małolepszy, Vito Di Noto, Maciej Krzywiecki, Jerzy K. Zak, Beata Dembinska, Enrico Negro, Krzysztof Miecznikowski, Magdalena Modzelewska, and Pawel J. Kulesza
- Subjects
Materials science ,Oxide ,iridium additive ,chemistry.chemical_element ,02 engineering and technology ,Carbon nanotube ,engineering.material ,010402 general chemistry ,lcsh:Chemical technology ,01 natural sciences ,reduced graphene oxide ,Catalysis ,law.invention ,lcsh:Chemistry ,chemistry.chemical_compound ,law ,lcsh:TP1-1185 ,Iridium ,Physical and Theoretical Chemistry ,platinum catalyst ,oxygen reduction reaction ,Gas diffusion electrode ,carbon nanotubes ,Graphene ,hydrogen peroxide intermediate ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Chemical engineering ,lcsh:QD1-999 ,engineering ,Noble metal ,0210 nano-technology ,Platinum - Abstract
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 &le, 2 µ, g cm&minus, 2, respectively) were considered as catalytic materials for the reduction of oxygen in acid media (0.5-mol dm&minus, 3 H2SO4). The electrocatalytic activity toward reduction of oxygen and formation of hydrogen peroxide intermediate are tested using rotating ring&ndash, 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&mdash, in iridium-containing systems&mdash, 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.
- Published
- 2020