“…Proton exchange membrane fuel cells (PEMFCs) have been attracting a lot of attention as promising energy converters, especially in automobile applications, because of their high efficiency, high energy density, high power density, zero emissions, and rapid cold start-up. − Membrane electrode assembly (MEA) as the most important part is the area of electrochemical reaction, especially catalyst layers (CLs) consisting of Pt/C as a catalyst and an electronic conductor, and Nafion as a proton transferred channel to extend the triple-phase boundary (TPB). , Many interfaces are formed during the self-assembly of Pt/C and Nafion due to some physical effects, such as the adsorption between platinum and Nafion, chelation between carbon black and platinum, the interaction between oxygenic groups on the surface of carbon black and Nafion and changes of Nafion structure in the electrocatalytic reaction. − These interfaces are also active sites of electrochemical reaction, where catalysts, electron pathway, and proton pathway are simultaneously contained to satisfy the special needs to make the electrochemical reaction. Cheng et al had confirmed that Nafion is able to promote the activity of platinum due to effective proton transfer and improvement of TPB . But the self-assembly of catalyst layer consisted of Pt/C and Nafion is yet to be understood, which plays a vital role to further significantly improve the power density of PEMFC.…”