Details

Autor(en) / Beteiligte

• Wang, Xiao Xia
• Prabhakaran, Venkateshkumar
• He, Yanghua
• Shao, Yuyan
• Wu, Gang

Titel

Iron‐Free Cathode Catalysts for Proton‐Exchange‐Membrane Fuel Cells: Cobalt Catalysts and the Peroxide Mitigation Approach

Ist Teil von

• Advanced materials (Weinheim), 2019-08, Vol.31 (31), p.e1805126-n/a

Ort / Verlag

Germany: Wiley Subscription Services, Inc

Erscheinungsjahr

2019

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• High‐performance and inexpensive platinum‐group‐metal (PGM)‐free catalysts for the oxygen reduction reaction (ORR) in challenging acidic media are crucial for proton‐exchange‐membrane fuel cells (PEMFCs). Catalysts based on Fe and N codoped carbon (Fe–N–C) have demonstrated promising activity and stability. However, a serious concern is the Fenton reactions between Fe2+ and H2O2 generating active free radicals, which likely cause degradation of the catalysts, organic ionomers within electrodes, and polymer membranes used in PEMFCs. Alternatively, Co–N–C catalysts with mitigated Fenton reactions have been explored as a promising replacement for Fe and PGM catalysts. Therefore, herein, the focus is on Co–N–C catalysts for the ORR relevant to PEMFC applications. Catalyst synthesis, structure/morphology, activity and stability improvement, and reaction mechanisms are discussed in detail. Combining experimental and theoretical understanding, the aim is to elucidate the structure–property correlations and provide guidance for rational design of advanced Co catalysts with a special emphasis on atomically dispersed single‐metal‐site catalysts. In the meantime, to reduce H2O2 generation during the ORR on the Co catalysts, potential strategies are outlined to minimize the detrimental effect on fuel cell durability. Co‐based catalysts have emerged as a promising alternate to Pt and Fe catalysts, and enable the cost and durability issues of proton‐exchange‐membrane fuel‐cell cathodes to be addressed. A comprehensive overview of current Co catalysts is provided in terms of their synthesis approaches, structures/morphologies, possible active sites, and catalytic activity/stability improvement, along with perspectives for the remaining challenges and future research directions.