Chemical composition and structure of carbon surfaces and their influence on the activities of carbon catalysts for the oxygen reduction reaction

Abstract

This article reviews the influence of heteroatom doping and the formation of warped graphitic layers on the catalytic activity of carbons for the oxygen reduction reaction (ORR). The development of a non-platinum cathode catalyst is key for the practical use of polymer electrolyte fuel cells (PEFCs), and carbon-based ORR catalysts are receiving special attention. First, we consider studies on the enhanced ORR activity of carbons caused by heteroatom doping. The type of dopant has been extended to elements other than nitrogen, and to multi-element doping. Possible mechanisms elucidating the enhanced ORR activity caused by heteroatom doping are given. Second, we mention the influence of the presence of the warped graphitic layers, which we consider to be an important factor for ORR activity. Finally, we show that combinations of these two factors, namely heteroatom doping and the presence of the warped graphitic layers, can further enhance ORR activity.