Performance durability of polyaniline-derived non-precious cathode catalysts

This research has focused on performance durability of the newly-developed polyaniline (PANI)-derived non-precious metal cathode catalysts. These catalysts show high oxygen-reduction activity in electrochemical and fuel cell testing, reflected by the onset and half-wave (E_1/2) potentials of oxygen reduction in RDE testing of 0.90 V and 0.77 V, respectively. Best-performing catalysts also exhibit insignificant H₂O₂ yield of less than 1%. Catalyst performance in fuel cell testing strongly depends on the choice of nitrogen precursors, transition metals used, and carbon supports. As expected, catalyst stability is affected by the operating voltage of the fuel cell, with more stable performance observed at low operating voltage and open cell voltage, than at intermediate voltages. Physical and electrochemical characterization of the catalysts, also in the presence of hydrogen peroxide, has been carried out to provide insight into the origin of possible degradation mechanisms.