Electrochemical Oxidation of Water Through Conducting Polymer for Hydroxyl Radical Generation at Ultra-Low Voltage.

Abstract

Although conducting polymers (CPs) have catalyzed the development of advanced optoelectronic devices, their performance in aqueous environments remains largely underexplored due to the quenching of electron/hole by water molecules. In this study, we present an unconventional electrochemical strategy to achieve unexpected hydroxyl radical (•OH) generation at a remarkably low voltage of 0.4 V (vs. Ag/AgCl). This is realized through an integrated system comprising CPs of poly(fluorene-alt-thienopyrazine) (PFTP) adsorbed onto the partially oxidized copper sheet. Microscopy and surface analysis techniques demonstrated that the Cu₂O layer on the copper sheet surface could enhance the interaction between PFTP and copper sheet, thereby tuning the oxidation potential of PFTP from 1.27 to 1.70 V (vs. Ag/AgCl). It was the specific shift that makes thermodynamically capable of oxidizing water into •OH upon electrical stimulation. Theoretical calculations and mass spectrometry imaging results indicated that the PFTP/Copper interaction is mainly attributed to the interaction between the S atoms on the PFTP backbone and Cu₂O sites, and the weak interfacial interaction effectively tuned the HOMO energy level of PFTP. Finally, the PFTP/Copper system demonstrates a superior sterilization rate of 99% against bacterial biofilms at low operating voltages, offering a sustainable and energy-efficient solution for anti-biofouling applications.