Abstract: Cost, durability, and fuel supply infrastructure remain the key problems barricading the successful commercialization of fuel cells. As for the proton exchange membrane fuel cells, the cost and durability of key materials come from Pt catalysts used in the fuel cells. Due to the various cost and resource issues regarding Pt, it is important for researchers to develop low-Pt fuel cell catalysts. Recently, core-shell structured electrocatalysts have attracted increasing attention because of their unique structure in reducing the amount of Pt. The recent de-velopment of the preparation methods and characterization techniques for core-shell structured catalysts are reviewed. First, an introduction to the preparation methods for the synthesis of core-shell structured electrocatalysts was presented, including the colloid method, electro-chemical method, and chemical reduction method. Among these methods, the colloid method is the most facile and controllable and has already been widely employed in the synthesis. Electrochemical and chemical reduction methods are the most promising methods that have been developed in the past several years. Then, the characterization techniques were discussed in details. Among these techniques, the high-angle annular dark field-scanning transmission electron microscopy developed during recent years is regarded as an effective way to characterize the core-shell structured catalysts. Finally, the application problems and some research trends were discussed and summarized.

Key words: fuel cell, platinum-based catalyst, core-shell structure, oxygen reduction reaction, under potential deposition