More conductive polypyrrole electrodeposited on substrates with close-packed gold nanoparticles

Recently, conductive polymers (CPs) of polypyrrole (PPy) have been widely applied in supercapacitors, gas sensors, photocatalyses and innovative cancer therapies. Chemical and electrochemical oxidation polymerizations are two general pathways for the preparation of PPy. The principal advantage of the electrochemical method is related to the prepared PPy with a better conductivity and its long-term stability. In this work, PPy films are innovatively electrodeposited on Pt substrates modified with Au nanoparticles (NPs) prepared by using sonoelectrochemical deposition-dissolving cycles (SEDDC). The modification of Au NPs demonstrates a catalytic electro-oxidation pathway for the polymerization of PPy. Encouragingly, the conductivity of PPy electrodeposited on this Au NPs-deposited Pt substrate is significantly increased by more than 6-fold of magnitude, as compared with that of PPy electrodeposited on a polished Pt substrate. The increased conductivity of PPy is consistent with its increased oxidation degree, oxidation level and longer conjugating length, and with its dopant ions being more stable during polymerization, which are revealed from analyses of Raman and X-ray photoelectron spectroscopies.