Developing cheap and stable membrane electrode assembly for proton exchange membrane water electrolysis (PEMWE) plays critical roles in renewable energy revolution. Iridium is the commonly efficient oxygen evolution reaction catalyst. But the reserve in earth is a shortage. Herein, an ordered array electrode in feature of the defective Ir film decorated on external WOx nanorods (WOxNRs) is designed. Electrodeposition is carried out to prepare an iridium coating (∼68 nm in thickness) to guarantee the ordered morphology. This novel electrode obtained brilliant I-V performances (2.2 A cm-2@2.0 V) and 1030 h stability (0.5 mA cm-2) with a reduced loading of 0.14 mgIr cm-2. The uniform dispersion Ir catalyst on the WOx substrate benefits to enhance Ir mass activity and improve the poor conductivity originating from WOx. Compared with that of sprayed electrode, the threshold current density of mass transport polarization region can be expande to at least 3.0 A cm-2 for ordered structure electrode attributed to the abundant water storage bulk. This novel Ir@WOxNRs electrode occupies a huge potential to defuse the cost and durability issues confronting with the PEMWE.
Keywords: Ir coating; PEM water electrolysis; WOx nanorod; electrode; oxygen evolution; stability.