Electrochemical deposition and dissolution of Fe species for N-doped carbon to understand the degradation mechanism of Pt-free oxygen reduction catalysts. (1st October 2016)

• Record Type: Journal Article
• Authors: Wu, Jiajia; Nabae, Yuta; Muthukrishnan, Azhagumuthu; Ohsaka, Takeo
• Is Part Of: Electrochimica acta. Volume 214(2016)
• Page Start: 307
• Page End: 312
• Publication Date: 2016-10-01
• Subjects: Oxygen reduction reaction -- Fe-containing nitrogen-doped carbon catalyst -- Durability test -- Activity decay -- Fe electrodeposition; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.08.006
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: The Fe electrodeposition-electrochemical dissolution improves ORR activity of P-PI. ORR activity decay occurs during the durability test of Fe-containing P-PI. Fe leaching is primarily responsible for the ORR activity decay. The electrochemical treatment is effective for the recovery of ORR activity. Abstract: The enhancement in oxygen reduction reaction (ORR) activity is achieved by the introduction of Fe species via the Fe electrochemical deposition-dissolution treatment into a metal-free nitrogen-doped carbon (P-PI) catalyst, which is prepared by the pyrolysis of polyimide fine particles. The thus-obtained Fe-containing P-PI catalyst suffers activity decay during the durability test, evidenced by the negative shift of half-wave potential, the decrease in limiting current density, the number of electrons transferred, and the ratio of the rate constant for 4-electron ORR to that for 2-electron process, and the increase in H2 O2 production percentage. The decayed ORR activity can be recovered by another Fe electrochemical deposition-dissolution treatment, demonstrating the predominant role of Fe leaching in activity degradation as well as the effectiveness of the electrochemical treatment in activity restoration.