Nanoporous PtIr Nanosheets as Bifunctional Electrocatalysts for Regenerative Proton Exchange Membrane (PEM) Fuel cells

The hydrogen economy is critical for deep decarbonization of the energy sector owing to high energy density of H₂ as a fuel, clean operation, and flexible implementation in terms of scale (W to GWs), source and end-use. To this date, proton exchange membrane water electrolyzers (PEMWEs) and fuel cells (PEMFCs) remain as emergent technologies for H₂ production and utilization due to the development in polymer electrolyte membranes, high current density operations, etc. These devices however operate in highly acidic conditions requiring significant amounts of platinum group metals (PGM)-based materials. Thus, widespread adoption of PEM devices depends on advancements in material development as well as device integration to lower total system costs and improve efficiencies.<br/>Our group has developed a novel approach to make nanoporous nanosheets of Ir (np-Ir NS). These np-Ir NS show superior catalytic activity and durability as anodic oxygen evolution reaction (OER) electrocatalysts in comparison to commercial IrO₂ nanoparticle catalysts. The unique morphology of nanoporous nanosheets allows support-free integration into catalyst layers and a form factor that results in significantly lower ohmic losses at high current density.¹<br/>In this work, we implement the previously developed, top-down approach to synthesize nanoporous nanosheets of PtIr (np-IrPt NS). These alloyed np-IrPt NS show excellent electrocatalytic properties for hydrogen oxidation reaction (HOR) and oxygen evolution reaction (OER), comparable with state-of-the-art PGM catalysts. Bifunctional catalytic properties make np-IrPt NS ideal candidates for regenerative fuel cell applications. We will also discuss the integration of np-IrPt NS into regenerative proton exchange membrane fuel cell (R-PEMFC) devices.<br/>References:<br/>1. Chatterjee and Peng et. al., <i>Adv. Energy. Mater.</i> <b>2021</b>, 11, 2101438