Synergistic effects in oxygen evolution activity of mixed iridium-ruthenium pyrochlores

0559769 - ÚFCH JH 2023 RIV GB eng J - Journal Article
Pittkowski, Rebecca - Abbott, D. F. - Nebel, Roman - Divanis, S. - Fabbri, E. - Castelli, I. E. - Schmidt, T. J. - Rossmeisl, J. - Krtil, Petr
Synergistic effects in oxygen evolution activity of mixed iridium-ruthenium pyrochlores.
Electrochimica acta. Roč. 366, JSN 2021 (2021), č. článku 137327. ISSN 0013-4686. E-ISSN 1873-3859
EU Projects: European Commission(XE) 722614 - ELCOREL
Institutional support: RVO:61388955
Keywords : Electrocatalysis * Oxygen evolution * Pyrochlores * Local structure optimization * Synergy
OECD category: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)
Impact factor: 7.336, year: 2021
Method of publishing: Limited access

Pyrochlore oxides (A(2)B(2)O(7)) simultaneously containing iridium and ruthenium in the B-site are promising catalysts for oxygen evolution reaction (OER) in acid media. The catalytic activity of the pyrochlore based catalysts is increased by the coexistence of Ir and Ru in the B-site of the pyrochlore structure. Lanthanide (Yb, Gd, or Nd) stabilized mixed pyrochlores with a fraction of Ru in the B-site of x(Ru) = 0.2, 0.4, 0.6, 0.8 were synthesized by the spray-freeze freeze-dry approach. All prepared mixed pyrochlore catalysts are surpassing the OER activity of the corresponding iridium and ruthenium analogues featuring no cation mixing as well as that of the benchmark IrO2 catalyst. The synergy of Ir and Ru in the B-site of the pyrochlore structure suppresses the effect of the A-site cation radius on the OER activity. The observed OER activity scales with the Ir-Ru bond distance which represents the local structure of the prepared materials. The most active ytterbium catalyst also shows a significant stability improvement under OER operando conditions over the benchmark IrO2. (C) 2020 Elsevier Ltd. All rights reserved.
Permanent Link: https://hdl.handle.net/11104/0332972