(IrOx – Pt)/Ti bifunctional electrodes for oxygen evolution and reduction. (1st November 2022)

• Record Type: Journal Article
• Authors: Touni, A.; Papoulia, Ch; Pavlidou, E.; Karfaridis, D.; Lambropoulou, D.; Sotiropoulos, S.
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 89(2022)
• Page Start: 37811
• Page End: 37830
• Publication Date: 2022-11-01
• Subjects: Bifunctional electrocatalysts -- Oxygen evolution reaction -- Oxygen reduction reaction -- IrOx-Pt electrocatalysts -- Galvanic deposition; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.08.275
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Mixed Ir–Pt electrocatalytic films on Ti metal supports were prepared via a galvanic deposition process. Two types of (Ir – Pt)/Ti electrodes were prepared with different Ir–Pt compositions (Ir/Pt atomic composition ratios of 1.74 and 0.44, based on ICP-MS measurements) and of a similar total metal loading (0.15 and 0.12 mg cm −2 ). The simultaneous deposition of both metallic Ir and Pt occurred spontaneously upon immersion of a freshly etched Ti metal substrate into a composite solution of Ir(IV) and Pt(IV) complexes of variable concentration. This was followed by electrochemical anodization to convert Ir to IrOx . Both electrodes showed homogeneous Ir and Pt dispersion on the Ti surface. The bifunctional electrocatalytic performance of (IrOx /Ir – Pt)/Ti electrodes has been tested towards the oxygen evolution (OER) and reduction (ORR) reactions in acidic solutions. The thus prepared Ti-supported Ir–Pt film electrodes exhibited satisfactory performance towards both reactions, with mass-specific currents for OER being higher than those at a single component IrOx/Ir/Ti electrode and the ones for ORR being comparable to those at a single component Pt/Ti electrode. Highlights: Bimetallic Pt–Ir/IrO2 catalysts were synthesized on a Ti substrate by a simple spontaneous galvanic deposition process. IrOx-Pt electrodes were studied for OER and ORR to be used as bifunctional electrocatalysts for the oxygen electrode of URFCs. The beneficial effect of Pt on Ir/IrO2 electrocatalytic activity towards OER has been demonstrated. Simultaneously with the previous point, the sustained ORR activity of Ir/IrO2 –Pt bi-component catalysts has been observed.