Improved experimental method for electroless deposition of iridium using a platinum sublayer to form a catalyst coated membrane

Abstract

The electroless deposition of iridium onto a perfluorosulfonated (Nafion) membrane is an important chemical reduction process that could produce cost-effective iridium catalysts for water electrolysis applications. A brief overview of the key components and advantages of electroless deposition are provided. The focus of this tutorial is then directed to electroless deposition of platinum and iridium, with the former serving as an intermediate “anchor layer” which improves the adhesion of iridium. The role of the electroless platinum layer is clearly defined, and the structural benefits of depositing the electroless platinum are provided. The lack of literature information on iridium electroless deposition is emphasized, followed with a brief discussion on iridium plating bath recipes and the choice of deposition substrate. The recipe and procedures for electroless platinum and electroless iridium are clearly outlined in rigorous detail, with the intent that this can be easily replicated in different laboratory environments. The membrane is first deposited with an electroless layer of platinum to serve as an anchoring layer for a subsequent iridium electroless deposition layer. Potential iridium recipe variants are mentioned as potential pathways for improving the final deposited iridium mass. A brief results section highlights the capabilities and scope of the recipe and can be used to inspire future development in this area of electrocatalysis.