Recent advances and perspectives of Ir-based anode catalysts in PEM water electrolysis

Proton exchange membrane water electrolysis (PEMWE) is a promising sustainable hydrogen production technology that can be effectively coupled with intermittent renewable energy. Currently, iridium (Ir) based catalysts are used that can well balance catalytic activity and stability in water oxidation. Herein, our attention is directed to the recent progress of Ir-based catalysts employed in PEMWE. We first briefly outline the basic working principle of PEMWE, key components, and their functions in the devices. Then, the latest progress of Ir-based anode catalysts and their practical applications in PEMWE are introduced in detail from the aspects of Ir-based single metals, Ir-based alloys, Ir-based oxides, and some supported Ir-based catalysts. Finally, the current problems and challenges faced by Ir-based anode catalysts in future development are commented on. It is concluded that the intrinsic catalytic activity can be significantly improved through precise structural design, morphology control, and support selection. Due to the strong corrosion under acidic conditions, the anti-dissolution of Ir active species should be carefully considered for catalyst fabrication in the future. Hopefully, the current efforts can help understand the current state of Ir-based anode catalysts and develop novel and effective catalysts for application in practical PEMWE. Recent advances and perspectives of Ir-based anode catalysts in PEM water electrolysis are highlighted, and it is concluded that the anti-dissolution and stability improvement of Ir active species should be carefully considered for catalyst design in the future.