Effects of poly-1,5-diaminoanthraquinone morphology on oxygen reduction in acidic solution

The poly-1,5-diaminoanthraquinone (P15DAAQ) modified Pt electrodes show electrocatalytic activity for oxygen reduction reaction (ORR) with oxygen reduction peak at about 0.39 V in 0.1 M H2SO4. The P15DAAQ with different thickness has different morphology. The effects of morphologies on the electrocatalytic behaviors of P15DAAQ for oxygen reduction reaction are investigated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) measurements. We propose two different O2-transport processes on electrodes modified with thin P15DAAQ and thick P15DAAQ. Together with the quantitative analysis with O2-transport dynamics, electron-transfer resistance, and catalytic reaction rate during ORR, thin P15DAAQ electrode performs better electrocatalysis for ORR, although thick P15DAAQ provides higher real surface area and more reactive sites which is beneficial for ORR within a short time.