Carbon-based catalysts by structural manipulation with iron for oxygen reduction reaction

Abstract

Acquiring a superior and stable nanostructure of carbon-based catalysts is of pivotal relevance for obtaining remarkable oxygen reduction reaction (ORR) performance. However, there is still no simple method to construct a satisfactory structure of carbon-based catalysts with copious and well exposed active sites, rendering the development of such a method for tuning the structure of catalysts timely and ultimately relevant. Here, we apply a facile and universal solid-state reaction to fulfil structural manipulation of carbon-based catalysts by iron, and report the successful production of a series of catalysts with distinct structures, i.e. carbon nanotubes, 3D crumpled and porous graphene nanostructures, and densely stacked graphene nanosheets. As a direct consequence of the superior nanostructure of 3D crumpled and porous graphene with Fe and N doping at the surface (Fe–N–G), the Fe–N–G catalyst produced with a modest content of Fe precursor displays the most outstanding ORR activity, even superior to that of Pt/C catalysts, and holds substantial promise as a substitute for noble-metal-containing Pt/C catalysts. We demonstrate for the first time that Fe species can be used to effectively modulate the nanostructures of carbon materials, offering new insight into the synthesis and applications of carbon materials as next-generation noble-metal-free catalysts.