Proton exchange membrane fuel cell (PEMFC) has important implications for the success of clean transportation in the future. One of the key factors affecting the cost and performance of PEMFC is the cathode electrocatalyst for the oxygen reduction reaction (ORR) to overcome sluggish kinetics and instability in an acidic environment. As an essential component of the electrocatalyst, the support material largely determines the activity, mass transfer, charge transfer, and durability of the electrocatalyst. Thereby, the support material plays a critical role in the overall performance of the electrocatalyst. Carbon-based materials are widely used as electrocatalyst supports because of their high porosity, conductivity, chemical stability, and tunable morphology. Recently, some new carbon-based materials with excellent structure have been introduced, such as carbon nanotubes, carbon nanowires, graphene, metal–organic framework (MOF)-derived carbon, and biomass-derived carbon materials. Combined with a variety of strategies, such as controllable construction of porous structures and surface defects, proper doping heteroatoms, the ingenious design of model electrocatalysts, and predictive theoretical calculation, a new reliable path was provided for further improving the performance of electrocatalysts and exploring the catalytic mechanism. Based on the topic of carbon-based materials for ORR in acidic medium, this review summarizes the up-to-date progress and breakthroughs, highlights the factors affecting the catalytic activity and stability of ORR electrocatalysts in acids, and discusses their future application and development.
