Overall Design of Anode with Gradient Ordered Structure with Low Iridium Loading for Proton Exchange Membrane Water Electrolysis

Insufficient catalyst utilization, limited mass trans-port, and high ohmic resistance of the conventional membrane electrode assembly (MEA) lead to significant performance losses of proton exchange membrane water electrolysis (PEMWE). Herein we propose a novel ordered MEA based on anode with a 3D membrane/catalytic layer (CL) interface and gradient tapered arrays by the nanoimprinting method, confirmed by energy dispersive spectroscopy. Benefiting from the maximized triple-phase interface, rapid mass transport, and gradient CL by overall design, such an ordered structure with Ir loading of 0.2 mg cm-2 not only greatly increases the electrochemical active area by 4.2 times but also decreases the overpotentials of both mass transport and ohmic polarization by 13.9% and 8.7%, respectively, compared with conventional MEA with an Ir loading of 2 mg cm-2, thus ensuring a superior performance (1.801 V at 2 A cm-2) and good stability. This work provides a new strategy of designing MEA for high-performance PEMWE.