2018/05/09 by Beata Dembińska, Dembinska, Beata, Magdalena Modzelewska +19
Chemistry · Energy · Engineering · #Chemical Physics (physics.chem-ph) #Electrocatalysts for Energy Conversion #Electrochemical Analysis and Applications #FOS: Physical sciences #Fuel Cells and Related Materials #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.1805.03390
openalex publication_date 2018/05/09 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
Hybrid systems composed of the reduced graphene oxide-supported platinum and\nmultiwall carbon nanotubes-supported iridium (both noble metals utilized at low\nloadings on the level of 15 and < 5 microg cm-2, respectively) have been\nconsidered as catalytic materials for the reduction of oxygen in acid media\n(0.5 mol dm-3 H2SO4). The electrocatalytic activity toward reduction of oxygen\nand formation of hydrogen peroxide intermediate have been tested using rotating\nring-disk electrode voltammetric experiments. The efficiency of the proposed\ncatalytic systems has also been addressed by performing galvanodynamic\nmeasurements with gas diffusion electrode half-cell at 80 \degC. The role of\ncarbon nanotubes is to improve charge distribution at the electrocatalytic\ninterface and facilitate the transport of oxygen and electrolyte in the\ncatalytic systems by lowering the extent of reduced graphene oxide restacking\nduring solvent evaporation. The diagnostic electrochemical experiments reveal\nthat at iridium-containing systems not only higher disk currents, but also much\nsmaller ring currents have been produced (compared to reduced graphene\noxide-supported platinum and its composite with bare carbon nanotubes), clearly\nimplying formation of lower amounts of the undesirable hydrogen peroxide\nintermediate. The enhancement effect coming from the addition of traces of\niridium (supported onto carbon nanotubes) to Pt, utilized at low loading, may\noriginate from the high ability of Ir to induce decomposition of the\nundesirable hydrogen peroxide intermediate. There is a competition between\nactivation (due to the presence of small amounts of Ir) and dilution (by carbon\nnanotubes) of Pt active centers in hybrid systems, therefore special attention\nis paid to the adjustment of their composition.\n