posted on 2023-12-18, 17:08authored byYan Shi, Chao Ding, Zhuoxin Lu, Lisha Shen, Kai Huang, Chenglin Zhao, Hongyi Tan, Chang-Feng Yan
In a proton exchange membrane water electrolyzer, directly
reducing
the Ir loading in the anode always leads to a decline in performance.
The limited in-plane electrical conductivity of the inhomogeneous
catalyst layer is one of the reasons that constrain the improvement
of cell performance. Herein, to enhance the activity of the low Ir
anode, continuous gold films with different thicknesses are coated
on a conventional IrO2 catalyst layer to form bilayer anodes.
The gold film acts as a bridge for connecting isolated IrO2 agglomerates, thus endowing an improved in-plane conductivity and
Ir mass activity. A significant improvement of cell performance is
observed with the bilayer anode, and the overpotential breakdown analysis
further interprets the origin of the performance enhancement. Moreover,
an electrochemical imaging technique by using the ex situ scanning
vibrating electrode technique is adopted for the direct observation
of the active area distribution of the electrode, and the mechanism
that how in-plane conductivity affects the Ir utilization is elucidated.