Anodic oxidation using 3D carbon felt/PbO₂ anode: a electron transfer-mediated system for degradation of Rhodamine B

This study investigates the use of porous structured carbon felt (CF) as a substrate for the preparation a lead dioxide (CF/PbO₂) anode for the electrochemical oxidation of Rhodamine B (RhB). Compared to traditional titanium-based lead dioxide (Ti/PbO₂) and graphite sheet-based lead dioxide (GS/PbO₂) anodes, the CF/PbO₂ anode exhibited superior electrocatalytic activity, achieving a RhB degradation efficiency exceeding 99%. After 10 cycles, the electrocatalytic activity of CF/PbO₂ anode remained robust, with a degradation efficiency of over 97%. Fluorescence spectroscopy, quenching experiments, and electrochemical tests indicate that the electrochemical oxidation behaviour on CF/PbO₂ and GS/PbO₂ anodes was governed by direct electron transfer, while indirect oxidation via ^•OH radicals was pivotal for the Ti/PbO₂ anode. LC-MS analysis identified the intermediates of RhB degradation, contributing to the proposed degradation pathway. This study provides an efficient anode for the electrochemical degradation of organic pollutants in water.