Anthraquinone (AQS)/polyaniline (PANI) modified carbon felt (CF) cathode for selective HO generation and efficient pollutant removal in electro-Fenton.

A novel binder-free anthraquinone (AQS)/polyaniline (PANI) modified carbon felt (CF) cathode for selective HO generation and efficient pollutant removal in electro-Fenton was fabricated by CV electro-deposition method. AQS, the oxygen reduction reaction (ORR) catalyst, was immobilized by the PANI film, which contributed to the obtained high stability of the AQS/PANI@CF cathode. The concentration of the electro-generated HO on AQS/PANI@CF cathode (83.3 μmol L) was about 10 times higher than that of the bare CF cathode. And the high yield of HO was attributed to the catalytic reduction of O by AQS to generate more superoxide radical (O), which combined with H to form HO. Additionally, the rhodamine B (RhB) degradation efficiency reached 98.8% within 60 min with the AQS/PANI@CF served as the cathode with high stability and good repeatability. The main generated reactive radicals were determined by the quenching experiments and the electron paramagnetic resonance (EPR) tests. Besides, a plausible mechanism of the AQS/PANI@CF cathode applied electro-Fenton process was proposed. This work provided a reliable reference for the subsequent investigations of the binder-free cathode with high performance and stability.