Journal Article

Unveiling the high-activity origin of single-atom iron catalysts for oxygen reduction reaction

Cheng, Daojian, Shui, Jianglan, Wan, Xin, Cao, Dapeng, Yang, Liu, Xiang, Zhonghua, Xu, Haoxiang, Zeng, Xiaofei

2018

Overview

It is still a grand challenge to develop a highly efficient nonprecious-metal electrocatalyst to replace the Pt-based catalysts for oxygen reduction reaction (ORR). Here, we propose a surfactant-assisted method to synthesize single-atom iron catalysts (SA-Fe/NG). The halfwave potential of SA-Fe/NG is only 30 mV less than 20% Pt/C in acidic medium, while it is 30 mV superior to 20% Pt/C in alkaline medium. Moreover, SA-Fe/NG shows extremely high stability with only 12 mV and 15 mV negative shifts after 5,000 cycles in acidic and alkaline media, respectively. Impressively, the SA-Fe/NG-based acidic proton exchange membrane fuel cell (PEMFC) exhibits a high power density of 823 mW cm−2. Combining experimental results and density-functional theory (DFT) calculations, we further reveal that the origin of high-ORR activity of SA-Fe/NG is from the Fe-pyrrolic-N species, because such molecular incorporation is the key, leading to the active site increase in an order of magnitude which successfully clarifies the bottleneck puzzle of why a small amount of iron in the SA-Fe catalysts can exhibit extremely superior ORR activity.

• Publisher: National Academy of Sciences
• Subject: Atoms & subatomic particles / Carbon / Catalysis / Catalysts / Chemical reduction / Chemical synthesis / Density functional theory / Engineering / Iron / Oxygen / Oxygen reduction reactions / Physical Sciences / Platinum / Proton exchange membrane fuel cells