An efficient foam Ni/MnO₂/Pd composite cathode for the electrocatalytic degeneration of phenol

In this study, a Nickel foam electrode modified with MnO₂ and Pd (i.e., a foam Ni/MnO₂/Pd electrode) was fabricated in two electrodeposition steps. First, MnO₂ was deposited on a three-dimensional cross-linked Ni foam electrode with high porosity and surface area through cyclic voltammetry. Then, the constant current method was used to deposit Pd electrically on the Ni foam electrode. The foam Ni/MnO₂/Pd cathode exhibited a phenol degradation rate of 91.6% at a current density of 2 mA/cm² for 2 h. This phenol degradation rate was higher than those of foam Ni/MnO₂ and foam Ni/Pd. Furthermore, the Pd on the foam Ni/MnO₂/Pd cathode was immobilized by depositing another thin layer of MnO₂ to form foam Ni/MnO₂/Pd/MnO₂, which reduced Pd loss in the cleaning process and improved reusability without decreasing the phenol degradation efficiency.