Metal oxide-based materials as an emerging platform for fuel cell system: a review

Polymer electrolyte fuel cells (PEFCs) are attractive energy resources in transportation and portable applications due to their low operational temperatures, excellent energy densities, and simplicity of storage. For the past decade, metal oxides (MO) have been identified as plentiful supplies with excellent electrochemical properties, low cost, an abundance of hydroxyl groups, and environmentally acceptable alternative to currently available materials. Their intriguing properties such as extremely large surface area, low synthesis cost, and so on, make them ideals for many applications. This review covered MO structure, characteristics, and current preparation methods. MO/metal nanoparticles and MO/carbon nanoparticles are also addressed as electrocatalysts, co-catalysts, or supports, especially in PEMFC and DMFC applications. This review also examined the effects of different MO nanoparticles in polymer and biopolymer membranes on membrane characteristics. Finally, the existing issues and future perspectives of MO nanoparticles are also discussed in this review. GRAPHICAL ABSTRACT