Tunable activity in electrochemical reduction of oxygen by gold-polyaniline porous nanocomposites

Oxygen electrochemical reduction on gold-polyaniline (Au-PANI) porous nanocomposite-modified glassy carbon electrode in basic media was described. The as-prepared Au-PANI porous nanocomposite showed superior tunable activity for electrochemical reduction of oxygen. The specific surface area of Au-PANI porous nanocomposites was evaluated to be about 11.3 m ²g ^-1 through a convenient voltammetric approach. Rotating ring-disk electrode experiments further demonstrated the number of electrons exchanged in oxygen reduction increased from 2e to 4e with increasing the trigger potential from 300, to 500, 700 mV. The tunable activity in electrochemical reduction of oxygen was achieved as a result of positive potential-induced formation and reduction of Au surface oxide. However, the tunable oxygen reduction reaction is fit for applying potential in a linear positive-going potential sweep. Irreversible ORR tunability was found after a more active surface formed at 700 mV. To optimize the applied potential window on these Au-based porous materials has potential applications such as in electrochemical sensing, fuel cells, or getting rid of the interference from the coexisted substances.