Catalytic Activity of Pd Ad-atoms for Electroless Ni-P Plating

Abstract

The initial deposition of electroless Ni-P films on gold electrodes modified with Pd ad-atoms was investigated using cyclic voltammetry and EQCM technique. It was found that the minimum coverage of Pd ad-atom catalysts is 0.01 for electroless Ni-P deposition. The initial deposition rates and the induction time for Ni-P plating are strongly influenced by the Pd coverage, and reached a maximum value at the coverage of 0.4. A maximum current density for H₂PO₂⁻ oxidation was observed at the Pd coverage of 0.45, where H₂PO₂⁻ adsorption is enhanced. The large amount of adsorbate of SO₄²⁻ or HSO₄⁻, which would inhibit H₂PO₂⁻ oxidation at the initial deposition of electroless Ni-P films, was observed at the Pd coverage of 0.45 in H₂SO₄ solution.