Importance of Electrocatalyst Morphology for the Oxygen Reduction Reaction

Abstract Proton/anion‐exchange membrane fuel cells (PEMFC and AEMFC), generating electricity from the H 2 energy with zero‐carbon emission, have become very promising energy conversion devices to meet the increasing energy demand and reduce the dependence on fossil fuels. Currently, platinum (Pt) based materials have proven to be the most efficient electrocatalysts for the oxygen reduction reaction (ORR) at the cathode of the PEMFC and AEMFC. However, the high price and the limited reserve of Pt greatly hinder their industrial applications. Recently, transition metal‐nitrogen‐carbon (M−N−C) based material, as an efficient alternative to replace the precious metal Pt‐based material, has attracted researchers’ attention. Great contributions have been devoted to develop M−N−C based electrocatalysts. This review summarizes recent advances on M−N−C based electrocatalysts used for ORR from the point view of morphology. One‐dimensional (1D), two‐dimensional (2D), three‐dimensional (3D) and multi‐dimensional (MD) M−N−C materials were discussed thoroughly with particular attention on the relationship between the structure and the catalytic activity.