Development of Ni‐Ir Oxide Composites as Oxygen Catalysts for an Anion‐Exchange Membrane Water Electrolyzer. Issue 5 (5th January 2022)

• Record Type: Journal Article
• Authors: Park, Deok‐Hye; Kim, Min‐Ha; Lee, Hak‐Joo; Lee, Woo‐Jun; Byeon, Jeong‐Hyeon; Kim, Ji‐Hwan; Jang, Jae‐Sung; Park, Kyung‐Won
• Is Part Of: Advanced materials interfaces. Volume 9:Issue 5(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-05
• Subjects: composite structures -- iridium oxide -- nickel oxide -- oxygen evolution reaction -- water splitting; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202102063
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: In water splitting, anode catalysts for the oxygen evolution reaction (OER), which is the rate‐determining step, are more critical than cathode catalysts. Herein, the authors prepare Ni‐IrO x composite catalysts consisting of NiO and IrO2 for the OER by a solid‐state reaction with different ratios of NiO to IrO2 and reaction temperatures. In particular, Ni‐IrO x ‐400 with a molar ratio of NiO/IrO2 = 1:1 heated at 400 ° C shows the best OER performance. In the overall water splitting test using an anion exchange membrane (AEM) water electrolyzer, the single cell with Ni‐IrO x ‐400 as the anode catalyst shows current densities of 1454.8 mA cm −2, respectively, measured at 1.8 V. Furthermore, the stability tests of the AEM single cells are carried out at 50 ° C under a constant current density of 500 mA cm −2 . The single cell with Ni‐IrO x ‐400 shows only a slight increase in the overpotential (rate: 2.0 mV h −1 ) for 100 h owing to the enhanced stability of Ni‐IrO x ‐400 compared to IrO2 (12.5 mV h −1 ). The improved OER performance of the Ni‐IrO x ‐400 may be attributed to a composite structure that can prevent particle agglomeration and thus preserve the active sites during the OER. Abstract : The anion exchange membrane electrolyzer fabricated using Ni‐IrO x composite catalyst exhibits a current density of 1125.3 mA cm −2 at 1.8 V and 50 °C and an overpotential increment rate of 2.5 mV h −1 at 500 mA cm −2 and 40 °C owing to a composite structure that can prevent particle agglomeration and preserve the active sites for the oxygen evolution reaction.