Highly active and stable synergistic Ir–IrO2 electro-catalyst for oxygen evolution reaction. Issue 7 (3rd July 2018)

• Record Type: Journal Article
• Authors: Zhou, Zhen-Hua; Sun, Wei; Zaman, Waqas Qamar; Cao, Li-Mei; Yang, Ji
• Is Part Of: Chemical engineering communications. Volume 205:Issue 7(2018)
• Page Start: 966
• Page End: 974
• Publication Date: 2018-07-03
• Subjects: Electrochemical catalyst -- hydrogen acceptor -- Ir–IrO2 composite -- oxygen evolution reaction; Chemical engineering -- Periodicals; 660.205
• DOI: 10.1080/00986445.2018.1423970
• Languages: English
• ISSNs: 0098-6445

Abstract

ABSTRACT: The design of efficient and stable electrocatalysts is still crucial to realize oxygen evolution reaction (OER) in acid and corrosive environment. Inspired by the metal/metal oxides catalysts, we hydrothermally synthesized Ir–IrO2 composites duly confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive spectrometer (EDS), X-ray absorption data, and transmission electron microscope results. A low onset over-potential of merely 234 mV and a Tafel slope of 53 mV dec −1 were obtained for the prepared catalyst Ir–IrO2 _0.5AF. In addition, Ir–IrO2 _0.5AF catalyst retained high activity for long time under constant potential polarization. The enhanced performance is attributed to the introduction of lower valence Ir as hydrogen acceptor: hydrogen transfers from –OOH intermediate in OER to adjacent H acceptor site, forming intermediate with relatively lower Gibbs free energy, and resulting in higher activity. The present study emphasizes on important role of the lower valence composition in launching H acceptors and providing wide opportunities toward rational designing of efficient and stable electro-catalysts.