(201a) IrO2 Nanopore MEA for Highly Efficient Oxygen Evolution Electrocatalyst in SPE

IrO₂ is a great candidate of anode electrode for its high OER activity and good stability. However, the high price of Ir hinders its extensive application¹. In this work, IrO₂ nanopore structure was synthesized with anodized TiO₂ (ATO) template. Most of reported works used ATO template prepared in organic solution, which had tiny or no gaps between the tubes and resulted in nanowire or nanotube structure of catalyst^2-4, High aspect ratio nanowire or nanotube may tend to crack during solid polymer electrolyzer (SPE) assembling. In contrast, ATO template synthesized in HF-H₃PO₄ aqueous solution showed well-separated tubes⁵ and IrO₂ could be electrodeposited on the external tube wall to form nanopore structure with large surface area, high oxygen evolution reaction (OER) activity and good mechanical property. The pore diameter was controlled by applying different voltage. Cyclic voltammetry and galvanostatic method was used to deposit IrO2 on the template. A membrane electrode assemble (MEA) for SPE was fabricated by hot-press method with IrO₂nanopore catalyst and Nafion membrane follow by acid treatment to remove the template.

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