A Polypyrrole-Modified Pd-Ag Bimetallic Electrode for the Electrocatalytic Reduction of 4-Chlorophenol

Abstract

A polypyrrole-modified bimetallic electrode composed of Pd-Ag on a Ti substrate (Pd-Ag/PPY/Ti) was successfully prepared via a chemical deposition method, and was applied to the electrocatalytic hydrodechlorination of 4-chlorophenol (4-CP) in aqueous solution. The electrode was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Various influences on the dechlorination efficiency of 4-chlorophenol, including applied current, initial pH value, and temperature, were studied. The dechlorination efficiency of 4-CP reached 94% within 120 min under the optimum conditions, i.e., a dechlorination current of 6 mA, an initial pH of 2.30, and a temperature of 303 K. The apparent activation energy of the dechlorination of 4-CP by the Pd-Ag/PPY/Ti electrode was calculated to be 49.6 kJ/mol. The equivalent conversion rate constant kPd was 0.63 L.gPd−1·min−1, which was higher than the findings presented in comparable literature. Thus, a highly effective bimetallic electrode with promising application prospects and low Pd loading was fabricated.

Palladium-Catalyzed Reactions

“…The electrocatalytic hydrodehalogenation of chlorophenols has been regarded as an attractive method for the removal of halogen atoms in chlorine-containing aromatic hydrocarbons, which represents a big issue from an environmental point of view. Wei et al have recently prepared a bimetallic electrode composed of Pd-Ag, which was applied to the electrocatalytic hydrodechlorination of 4-chlorophenol in water [6]. This new electrode, obtained via chemical deposition, exhibits high performances with low Pd loadings, and, for these reasons, industrial application prospects are expected.…”