High-Efficiency Iridium-Yttrium Alloy Catalyst for Acidic Water Electrolysis

Proton exchange membrane (PEM) water electrolysis holds great promise in revolutionizing clean energy production by enabling the efficient generation of hydrogen. Nevertheless, a formidable challenge persists in the realm of designing electrocatalysts that are both highly active and acid-resistant during the oxygen evolution reaction (OER), thereby mitigating the substantial kinetic barrier. In this study, the facile synthesis of iridium-yttrium (IrY) alloy nanocatalysts via a thermal shock method is introduced, which exhibits exceptional activity in the context of acidic water oxidation. Through the strategic incorporation of dispersed Y into the lattice of Ir metal, the IrY catalyst demonstrates a notably low overpotential of 255 mV at a current density of 10 mA cm −2 and showcases remarkable catalytic stability in acidic electrolytes, enduring for over 500 h with a high current density of 100 mA cm −2 . Through a comprehensive set of in situ characterizations and analytical methods, the formation of a surface Ir-based oxide layer, induced by deprotonation and electrochemical oxidation is unveiled, which is notably stabilized by the presence of Y dopants. This stabilization of the active site imparts enhanced resistance to over-oxidation and dissolution, underpinning the exceptional stability of the catalyst. Theoretical calculations suggest that the incorporation of Y into the catalyst structure has a significant impact on enhancing the reactivity of the oxygen intermediate (O*) at adjacent Ir sites, thus lowering the overpotential and promoting OER activity. The alloying approach presents a straightforward method for achieving atomic-level modifications in catalyst design and can pave the way for the development of more effective and economically viable OER catalysts and beyond.