Improved electrode durability using a boron-doped diamond catalyst support for proton exchange membrane fuel cells

Abstract

The durability of a fuel cell electrode was improved by using a boron-doped diamond (BDD) electrode support. BDD nanoparticles were synthesized by a size-controllable electrostatic self-assembly method (ESA). Moreover, the morphological changes as a function of operating time were investigated to prove the durability enhancement. First, diamond seeds were formed by an ESA method. The BDDs were then synthesized around these seeds by a conventional hot-filament chemical vapor deposition process. A Pt catalyst was then deposited by the polyol method, and it was characterized by scanning electron microscopy and transmission electron microscopy. The supporting BDD particles were 100-200 nm in size, whereas the Pt catalyst particles were 2-4 nm. Multiwalled carbon nanotubes (MWCNTs) and a conventional supporting material (Vulcan XC-72) were also studied for comparison. The electrochemical characteristics were examined by cyclic voltammetry and unit cell tests. The BDD support showed a larger surface area and better performance than the MWCNT and Vulcan XC-72 supports. According to the accelerated long-term stability tests, the BDD support material was more stable than the MWCNT and Vulcan XC-72 supports. These results show that BDD supports improve the durability of the fuel cell electrode.