Effect of catalyst layer designs for high-performance and durable anion-exchange membrane water electrolysis

Abstract

Development of anode design is crucial for highly efficient and durable anion-exchange membrane water electrolysis (AEMWE) as the kinetic of oxygen evolution reaction (OER) is sluggish. In this study, a macroporous catalyst layer (macroporous_CL) was proposed as an anode design for AEMWE to enhance the catalyst utilization. A macroporous_CL contains pores of two main size ranges: hundreds of nanometers and hundreds of micrometers. It is prepared using a spraying method to form nanometer-sized pores. The use of a stainless-steel (SUS) porous transport layer (PTL) as the substrate of the spraying method produces micrometer-sized macropores. In an investigation of the effects of the macroporous_CL and conventional catalyst layer (plain_CL) on AEMWE using two different kinds of oxygen evolution reaction (OER) catalysts, the macroporous_CL exhibited higher performance with lower ohmic and charge-transfer resistances compared to the plain_CL. This performance enhancement was attributed to the improved catalyst utilization and electron transport. Also, the macroporous_CL showed better durability compared to the plain_CL. Therefore, the macroporous_CL has been considered as an alternative anode design for AEMWE.