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Water‐Splitting Electrocatalysis in Acid Conditions Using Ruthenate‐Iridate Pyrochlores
Author(s) -
Sardar Kripasindhu,
Petrucco Enrico,
Hiley Craig I.,
Sharman Jonathan D. B.,
Wells Peter P.,
Russell Andrea E.,
Kashtiban Reza J.,
Sloan Jeremy,
Walton Richard I.
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201406668
Subject(s) - pyrochlore , electrocatalyst , catalysis , oxygen evolution , ruthenium , redox , xanes , nanocrystalline material , electrochemistry , hydrothermal circulation , materials science , inorganic chemistry , infrared spectroscopy , water splitting , chemistry , chemical engineering , spectroscopy , electrode , nanotechnology , photocatalysis , engineering , phase (matter) , biochemistry , physics , organic chemistry , quantum mechanics
Abstract The pyrochlore solid solution (Na 0.33 Ce 0.67 ) 2 (Ir 1− x Ru x ) 2 O 7 (0≤ x ≤1), containing B‐site Ru IV and Ir IV is prepared by hydrothermal synthesis and used as a catalyst layer for electrochemical oxygen evolution from water at pH<7. The materials have atomically mixed Ru and Ir and their nanocrystalline form allows effective fabrication of electrode coatings with improved charge densities over a typical (Ru,Ir)O 2 catalyst. An in situ study of the catalyst layers using XANES spectroscopy at the Ir L III and Ru K edges shows that both Ru and Ir participate in redox chemistry at oxygen evolution conditions and that Ru is more active than Ir, being oxidized by almost one oxidation state at maximum applied potential, with no evidence for ruthenate or iridate in +6 or higher oxidation states.