Electro-polymerization fabrication of PANI@GF electrode and its energy-effective electrocatalytic performance in electro-Fenton process

Abstract

An energy-effective polyaniline coated graphite felt (PANI@GF) composite cathode for the electro-Fenton (E-Fenton) process was synthesized through an electro-polymerization method. The electrocatalytic activity of the cathode for the 2e− ORR process was investigated and dimethyl phthalate (DMP) was used as a model substrate to evaluate its performance in the E-Fenton process. The as-prepared PANI@GF composite possessed a three-dimensional porous structure, which is favorable for O2 diffusion, while the large amount of N atoms in the conductive polyaniline (PANI) enhanced 2e− ORR reactivity. The DMP degradation of the E-Fenton system using PANI@GF was significantly enhanced owing to the improvement in ORR performance. The apparent kinetic constant for DMP degradation was 0.0753 min−1, five times larger than that of GF. The optimal carbonization temperature and polymerization time for the preparation of the PANI@GF composite cathode was found to be 900 °C and 1 h, respectively. Measurement conditions are a crucial factor for proper evaluation of cathode electrocatalytic performance. Accordingly, the O2 flow rate, Fe2+ concentration, and pH for DMP degradation were optimized at 0.4 L/min, 1.0 mmol/L, and 3.0, respectively. These results indicate that the present PANI@GF composite cathode is energy-effective and promising for potential use as an E-Fenton system cathode for the removal of organic pollutants in wastewater.