The effect of iridium content in boron carbide-supported iridium catalyst on the activity and stability of proton exchange membrane water electrolyzer
Jahowa Islam, Sang-Kyung Kim, Md Mizanur Rahman, Phan Thanh Thien, MinJoong Kim, Hyun‐Seok Cho, Changsoo Lee, Jae Hun Lee, Sechan Lee
Abstract
One of the major obstacles to proton exchange membrane water electrolyzer (PEMWE) for large-scale applications is the cost of iridium for oxygen evolution reaction (OER). To resolve this issue, boron carbide-supported iridium catalysts are prepared by varying the iridium content from 10 to 60 wt%. Increasing the iridium content on the boron carbide support affects the physical properties of the catalysts and the electronic structure of iridium. At the content of 40%, Ir/B4C showed the highest catalytic activity mainly due to its high electrochemical surface area. 40%-Ir/B4C showed outstanding cell performance of 1.0 A/cm2 at 1.61 V with a loading of 0.5 mg⋅Ir/cm2 which has the same performance with 3.0 mg⋅Ir/cm2 of unsupported commercial catalyst. 40%-Ir/B4C also showed excellent durability in a half-cell as well as in a single cell. The presence of Ir (IV) and the metal-support interaction help 40%-Ir/B4C to be stable.