Tuning amorphous Ir-IrOx oxygen evolution catalyst via precursor complexation for efficient and durable water electrolysis

• Published in: Applied surface science Vol. 606; p. 155008
• Main Authors: Gu, Fangwei, Zheng, Lufan, Wei, Hailong, Mi, Wanliang, Zhang, Cong, Su, Qianqian, Zhu, Wei, Lin, Wei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30-12-2022
• Subjects: Amorphous IrOx; Complexation; Oxygen evolution reaction; Proton exchange membrane water electrolysis; Complexation; Amorphous IrOx; Oxygen evolution reaction; Proton exchange membrane water electrolysis
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.155008

A novel complexation method was reported to prepare a heterostructured Ir-IrOx OER catalyst with controllable amorphous IrOx surface and optimizable OER activity.
[Display omitted]
•A heterostructured Ir-IrOx OER catalyst is synthesized via a precursor complexation method for the first time.•The amorphous IrOx surface and Ir oxidation states can be tuned by alternatives of complexes and calcination temperatures.•The high activity and stability of Ir-IrOx catalysts were verified in RDE test and PEMWE cell test.•The appropriate ratio of amorphous IrOx surface to Ir skeleton was demonstrated to be a key factor related to OER activity.
Sluggish kinetics and corrosive condition of oxygen evolution reaction (OER) make it the bottleneck of proton exchange membrane water electrolyzer (PEMWE). It is essential to develop facile and scalable synthetic methods to elevate the activity and stability of OER electrocatalysts. We report a precursor complexation method to prepare a Ir-IrOx OER catalyst with crystalline Ir skeleton and amorphous IrOx surface. The appropriate valence states of amorphous IrOx surface and Ir skeleton were the probable origins of high activity and durability for OER by tuning the complexes and calcination temperature. An increasing calcination temperature and a complex with high decomposition rates led to more fractions of oxide surface as well as high valence state of Ir. The Ir-IrOx catalyst only required an overpotential of 228 mV to attain a current density of 10 mA cm−2, surpassing most reported Ir-based catalysts. A PEMWE equipped with the Ir-IrOx OER catalyst reached a current density of 1 A cm−2 at a low cell voltage of 1.67 V at 80 °C, and the applied voltage was almost unchanged in the 100 h’ chronopotentiometry test, suggesting the potential practicability of the catalysts.