新しい鉄の触媒が、ついに水素燃料電池を安価に実現するかもしれない – 水素燃料電池を安価に購入できるようになる(New iron catalyst could – finally!- make hydrogen fuel cells affordable)

プラチナが高価なため、環境に優しい燃料の商業化を何十年も妨げてきたのですが、この低コスト触媒はその代替となり得ることが研究で明らかになりました。 Study shows the low-cost catalyst can be a viable alternative to platinum that has stymied commercialization of the eco-friendly fuel for decades because it’s so expensive

2022-07-07 バッファロー大学(UB)

＜関連情報＞

• https://www.buffalo.edu/news/releases/2022/07/006.html
• https://www.nature.com/articles/s41560-022-01062-1

燃料電池用高活性・高耐久性酸素還元触媒としての窒素-炭素コーティングされた原子状鉄サイト Atomically dispersed iron sites with a nitrogen–carbon coating as highly active and durable oxygen reduction catalysts for fuel cells

Shengwen Liu,Chenzhao Li,Michael J. Zachman,Yachao Zeng,Haoran Yu,Boyang Li,Maoyu Wang,Jonathan Braaten,Jiawei Liu,Harry M. Meyer III,Marcos Lucero,A. Jeremy Kropf,E. Ercan Alp,Qing Gong,Qiurong Shi,Zhenxing Feng,Hui Xu,Guofeng Wang,Deborah J. Myers,Jian Xie,David A. Cullen,Shawn Litster & Gang Wu
Nature Energy

Abstract

Nitrogen-coordinated single atom iron sites (FeN₄) embedded in carbon (Fe–N–C) are the most active platinum group metal-free oxygen reduction catalysts for proton-exchange membrane fuel cells. However, current Fe–N–C catalysts lack sufficient long-term durability and are not yet viable for practical applications. Here we report a highly durable and active Fe–N–C catalyst synthesized using heat treatment with ammonia chloride followed by high-temperature deposition of a thin layer of nitrogen-doped carbon on the catalyst surface. We propose that catalyst stability is improved by converting defect-rich pyrrolic N-coordinated FeN₄ sites into highly stable pyridinic N-coordinated FeN₄ sites. The stability enhancement is demonstrated in membrane electrode assemblies using accelerated stress testing and a long-term steady-state test (>300 h at 0.67 V), approaching a typical Pt/C cathode (0.1 mg_Pt cm⁻²). The encouraging stability improvement represents a critical step in developing viable Fe–N–C catalysts to overcome the cost barriers of hydrogen fuel cells for numerous applications.