Water‐Splitting Electrocatalysis in Acid Conditions Using Ruthenate‐Iridate Pyrochlores1. Issue 41 (4th September 2014)

• Record Type: Journal Article
• Authors: 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.
• Is Part Of: Angewandte Chemie international edition. Volume 53:Issue 41(2014)
• Page Start: 10960
• Page End: 10964
• Publication Date: 2014-09-04
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201406668
• Languages: English
• ISSNs: 1433-7851

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The pyrochlore solid solution (Na_0.33Ce_0.67)₂(Ir_{1−<italic>x</italic>}Ru_{<italic>x</italic>})₂O₇ (0≤<italic>x</italic>≤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&lt;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)O₂ 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.</p> </abstract>