The aim of the work is to form efficient and inexpensive nanostructured catalysts by electroplating 3D structure metal copper-nickel (Cu-Ni) foams on titanium (Ti) surface and decorating them with low amounts of platinum nanoparticles (PtNP) for the electrooxidation of sodium borohydride (NaBH₄). The Cu-Ni foam was prepared by electrochemical deposition (I_deposition=1.5 Acm^-2, t_deposition= 3,6 and 9 min) on Ti surface. The electrolyte contained 0.5 M Ni²⁺ ions, and the concentrations of Cu²⁺ ions ranged from 0.01 to 0.02 M.

PtNP particles were deposited on Cu-Ni foam (noted (Pt(Cu-Ni)/Ti)) by immersion of Cu-Ni foam into 1 mM H₂PtCl₆ solution at 25 °C for 1 minute. The morphology and composition of the prepared catalysts were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The electrocatalytic activity of the 3D catalysts was evaluated towards the oxidation of borohydride by cyclic voltammetry method in 0.05 M NaBH₄ solution in an alkaline media in the potential range from -1.2 to 0.6 V (vs. Ag/AgCl) and with an electrode potential scan rate of 10 mVs^-1.

The study showed that the prepared 3D Cu-Ni foam and Pt(Cu-Ni)/Ti have good electrochemical stability in alkaline NaBH₄ solution. It was also observed that immersion of Cu-Ni foam in a platinum-containing solution for 1 min increased the electrocatalytic activity of the prepared Pt(Cu-Ni)/Ti catalysts for NaBH₄ oxidation compared to Cu-Ni foam.

Acknowledgment

This project has received funding from European Social Fund (project No 09.3.3-LMT-K-712-19-0138) under a grant agreement with the Research Council of Lithuania (LMTLT).