Fe/Co-based nanoparticles encapsulated in heteroatom-doped carbon electrocatalysts for oxygen reduction reaction

Abstract

It is crucial to develop low-cost and highly efficient catalysts for oxygen reduction reaction (ORR) which is the key process in electrochemical energy conversion and storage devices. Transition metal-based nanoparticles/carbon materials are an important class of non-noble metal catalysts that have attracted considerable research interest. The topic of this review is mainly focused on carbon encapsulated Fe/Co-based nanoparticles catalysts for ORR, and these catalysts are summarized in categories of metals, oxides, carbides, phosphides, sulfides and hybrid nanoparticles. The structures and morphologies of the carbon matrix as well as compositions of nanoparticles have great influence on the catalytic performance. Numerous catalysts display excellent ORR activity and stability in alkaline media but only a few are efficient in acidic media. In addition, challenges and further strategies on the development of this type of carbon encapsulated nanoparticles catalysts are also proposed.