Mesoporous carbon with uniquely combined electrochemical and mass transport characteristics for polymer electrolyte membrane fuel cells

The design of electrodes for polymer electrolyte membrane fuel cells (PEMFCs) is a delicate balance of electrochemical and mass transport issues. High performance fuel cell electrode materials require nanoarchitectures with established nanoscopic reaction zones and efficient molecular transport of gasor liquid-phase reactants and products to and from the electrochemical reaction zones. Mesoporous carbon (MC), with uniquely combined electrochemical and mass transport characteristics is an ideal electrode material for polymer electrolyte membrane fuel cells as its mesoscopic structures not only enables electrocatlysts to be highly dispersed, but also offers ideal pore morphologies that facilitate mass transport. Recently, a wide variety of applications of MCs in PEMFCs have been exploited. This article provides a review of these past efforts with an attempt to gain a better understanding of the role of MCs in PEMFCs. The contribution of MCs in the gas diffusion layer is addressed first and their roles in the catalyst layer are then discussed. The advantages and disadvantages, the acting mechanism to promote electrochemical and mass transport characteristics, and the strategies to improve present electrode materials are discussed.