Electrohemical synthesis of high active palladium-based catalysts for fuel cell

Abstract

This thesis presents a facile and simple stepwise electroless deposition method for the synthesis of palladium nanoparticles for fuel cell application. The palladium nanoparticles synthesized by the proposed method exhibited high specific and mass activity for both oxygen reduction reaction and formic acid oxidation compared to commercial platinum and palladium loaded carbon. In particular, the amorphous palladium-phosphorus nanoparticles exhibited the highest specific and mass activity reported in literature so far. For oxygen reduction reaction, the palladium-phosphorus nanoparticles had a specific and mass activity of 6.85 mA cm-2 and 2.21 mA µg-1 respectively which were 4.5 and 2.6 times greater than previously reported values. Furthermore for formic acid oxidation, the palladium-phosphorus nanoparticles had a specific and mass activity of 5.7 mA cm-2 and 2.9 mA µg-1 respectively which were also higher than any previously reported literature values. The palladium nanoparticles where also shown to be more durable than commercial platinum and palladium loaded carbon. Furthermore, the palladium nanoparticles synthesized by the proposed method were also demonstrated to be industrial applicable. Lastly, the proposed synthesis method was also implemented in coating carbon nanotubes with palladium nanoparticles to make a palladium nanoparticles-carbon nanotubes composite. This palladium nanoparticles-carbon nanotubes composite was shown to be able to increase the catalytic and mass activity of bilirubin oxidase in oxygen reduction reaction compared to carbon nanotubes alone. Furthermore, this palladium nanoparticles- carbon nanotubes composite was also demonstrated to be able to increase the electron transfer rate between the bilirubin oxidase and the electrode (99.2 s-1 to 169.4 s-1).