Nano-size IrOx catalyst of high activity and stability in PEM water electrolyzer with ultra-low iridium loading

Nano-size IrOx catalyst of high activity and stability in PEM water electrolyzer with ultra-low iridium loading

TitleNano-size IrOx catalyst of high activity and stability in PEM water electrolyzer with ultra-low iridium loading
Publication TypeJournal Article
Year of Publication2018
AuthorsHaoran Yu, Nemanja Danilovic, Yang Wang, William Willis, Abhinav Poozhikunnath, Leonard Bonville, Chris Capuano, Katherine Ayers, Radenka Maric
JournalApplied Catalysis B: Environmental
Volume239
Pagination133 - 146
Date Published12/2018
ISSN09263373
Abstract

The balance of catalyst loading, activity and stability remains a challenge for the anode of proton exchange membrane (PEM) water electrolyzers. Here we report a nano-size IrOx/Nafion® composite catalyst that exhibits both outstanding activity for oxygen evolution reaction (OER) and stability in a PEM water electrolyzer. The IrOx/Nafion® catalyst layer is fabricated using a flame-based cost-effect process, reactive spray deposition technology. The IrOx/Nafion® catalyst shows >10 times improvement in OER mass activity compared to IrOx nanoparticles synthesized using the wet chemistry method. The IrOx/Nafion® catalyst also achieved ∼4,500 h of stable operation in MEA electrolyzer at 1.8 A cm−2 and 80 °C with ultra-low iridium loading of 0.08 mg cm−2. Analysis of the IrOx structure and the electrochemical performance revealed three key factors for balancing high stability and activity: (1) high ratio of Ir (IV) to Ir (III) species and high content of hydroxide on the surface; (2) high anodic charge and surface area due to nano-size IrOx particles that are well-dispersed in the Nafion® ionomer electrolyte; (3) homogeneous anode catalyst layer morphology.

DOI10.1016/j.apcatb.2018.07.064
Short TitleApplied Catalysis B: Environmental
Refereed DesignationRefereed