Pd/PANI/Ti composite electrocatalyst with efficient electrocatalytic performance: Synthesis, characterization, stability, kinetic studies, and degradation mechanism

The unique structure of benzene ring and chloride ion makes chlorophenol pollutants have a great influence on biology and ecology. Due to its environmental friendliness, electrochemical methods have been widely used to degrade chlorophenol pollutants. Herein, the palladium/polyaniline/titanium (Pd/PANI/Ti) composite electrodes were prepared by the constant current method due to the high catalytic activity of palladium and the high specific surface area of polyaniline. The morphology, crystal structure, element valence, and functional groups of the composite electrodes were observed and analyzed by SEM, XRD, XPS, and FT-IR. The degradation efficiency of 2, 4-DCP in NaCl solution was up to 96.54% for 8 min and 100% for 10 min, respectively. The results show that the best removal efficiency of 2, 4-DCP by Pd/PANI/Ti electrode is as follows: the aniline concentration is 5 mL/L, the preparation voltage is 20 V, the concentration of PdCl2 is 10 μmol/L, the pH is 3, and the electrolyte NaCl concentration is 0.20 mol/L. The kinetics of the 2, 4-DCP degraded by Pd/PANI/Ti electrode was found to be pseudo-first-order kinetics and was fitted to the Langmuir–Hinshelwood model. The degradation products were analyzed by LC-EIS-MS. The removal efficiency of 2,4-DCP remained basically unchanged after 20 times of continuous use. The good removal efficiency of 2, 4-DCP indicates that this electrode is a promising material in the practical application of removing chlorophenol pollutants from water. Finally, the degradation pathway of 2,4-DCP was put forward.