Oxygen reduction reaction in methanol fuel cells

Fuel cells are promising alternative sources of energy to address the prevailing energy crisis, which yields energy via electrochemical oxidation and reduction processes. Amid the diverse fuel cells used, direct methanol fuel cell (DMFC) invites great appreciation owing to its superior energy density, accessibility, and user-friendly handling of the fuel methanol. Methanol oxidation reaction (MOR) on the anode and oxygen reduction reaction (ORR) on the cathode are the two reactions in DMFC. However, the sluggish nature of ORR leads to a decline in the overall efficiency of DMFC. Therefore, investigations are active in designing a highly efficient, methanol tolerant, cost-effective, and stable catalyst for the oxygen reduction reaction. This chapter discusses various types of ORR catalysts, their merits, and demerits. In addition, the various catalyst support is also discussed in the chapter.