Modification of a Pd-loaded electrode with a carbon nanotubes–polypyrrole interlayer and its dechlorination performance for 2,3-dichlorophenol

Abstract

A novel Pd loaded Ti electrode was prepared with a carbon nanotubes and polypyrrole interlayer modification, referred to as a Pd/CNTs–PPy/Ti electrode. Pretreated CNTs were deposited on the substrate uniformly by electrophoretic deposition technique. Modification by the CNTs–PPy interlayer made the Pd particles smaller and well-distributed. Pulsed-current electrodeposition technique led to more compact Pd particles. The hydrogen adsorption current value increased 55.3% and the electrochemical active surface area (EASA) increased 58.7% compared to the electrode without modification. The prepared Pd/CNTs–PPy/Ti electrode was employed in dechlorination of 2,3-dichlorophenol (2,3-DCP) in aqueous solution. The potential impact factors on the electrocatalytic dechlorination were studied, including dechlorination current, initial pH value of catholyte, reaction temperature and common ions in aqueous solution. Complete dechlorination could be achieved within 70 min under the selected conditions i.e., current of 5 mA, and an initial pH of 2.5 at ambient temperature. The common ions in aqueous solution, such as NO₃⁻, CO₃²⁻, HCO₃⁻, Mg²⁺, K⁺ and Ca²⁺, had no obvious effect on the electrocatalytic dechlorination within the scope of this investigation. The prepared Pd/CNTs–PPy/Ti electrode exhibited promising dechlorination potential with higher electrochemical activity.