Electrocatalytic hydrogenolysis of chlorophenols in aqueous solution on Pd58Ni42 cathode modified with PPy and SDBS

• High electrocatalytic activity of Pd58Ni42 electrode was achieved by the synergistic effect of PPy and SDBS.
• Pd loading of the electrode modified with PPy and SDBS decreased by 0.35 mg/cm2.
• Complete decomposition of PCP and 2,4-DCP was achieved within 90 min.
• Proposed reaction pathways for 2,4-DCP and PCP dechlorination were discussed.
• The formation of PPy film improved the stability of Pd58Ni42(SDBS)/PPy/Ti cathode.

Electrocatalytic hydrogenolysis (ECH) of chlorophenols in aqueous solution was achieved on a novel electrode. Polymeric pyrrole (PPy) film and surfactant sodium dodecylbenzene sulfonate (SDBS) were used for preparation of Pd–Ni bimetallic cathode, which was marked as Pd58Ni42(SDBS)/PPy/Ti cathode due to Pd and Ni loading amounts. High electrocatalytic activity could be achieved, by the synergistic effect of PPy and SDBS, meanwhile, the loading of Pd could be decreased by 0.35 mg/cm2. Effective dechlorination processes of pentachlorophenol (PCP) and 2,4-dichlorophenol (2,4-DCP) were investigated. Complete decomposition of PCP could be achieved under the conditions of current of 5 mA, initial pH in cathode compartment of 2.0 and dechlorination time of 90 min. Complete dechlorination of 2,4-DCP could be achieved under current of 5 mA, initial pH of 1.7 and dechlorination time of 90 min. Pathways were inferred according to instantaneous molar concentration of the intermediate products. The formation of PPy film improved the stability of Pd58Ni42(SDBS)/PPy/Ti cathode. The electrode exhibited promising dechlorination potential with high electrocatalytic activity, good stability and low cost.