The electrocatalytic dechlorination of 4-chlorophenol (4-CP) in aqueous solution was studied by using a palladium-nickel bimetallic composite catalyst deposited on nickel foam (Pd-Ni/Ni foam) as the cathode.The Pd-Ni composite particles with a diameter of less than 50 nm were finely dispersed on the Ni foam surface.The Pd-Ni/Ni foam electrode exhibited higher dechlorination efficiency than single Pd or Ni supported on Ni foam electrodes.High-performance liquid chromatography analysis verified that phenol was the main dechlorination product.For an applied current of 20 mA

a bulk solution temperature of 15℃

and an initial 4-CP concentration of 1 mmol·L-1

dechlorination efficiency of 82% was observed.Based on electrochemical impedance spectroscopic results and the current efficiency of 4-CP dechlorination at different applied currents on various electrodes

the authors determined the rate-limiting step under various polarization conditions in the experiments.