▎ 摘　　要

The aim of this study is to extend the knowledge of possible improvements in graphene-supported PtCoFe electrocatalysts synthesized through different thermal treatment procedures. Electrocatalysts are prepared via the reduction of precursors followed by thermal treatment at three different temperatures. A freeze-drying procedure is also used instead of conventional drying to extend the knowledge of possible improvements in electrocatalysts. In the single cell tests, the electrocatalyst nanoparticles, which are synthesized by freeze-drying procedures, show higher performance than the other electrocatalysts. This may be due to more triple-phase boundaries being created in the freeze-dried electrocatalyst because of the increased d(002) and its well-arranged spacing of the nanostructure. The power density of the proton exchange membrane fuel cell (PEMFC) with the synthesized cathode electrocatalyst with low metal loading (0.1 mg cm(-2) Pt) can reach a maximum of 450 mW cm(-2) at 75 degrees C, which indicates its potential application in PEMFCs.