In the present work, the smooth and fiber-shaped Co coatings decorated with Pt crystallites were investigated as the anode material in direct borohydride-hydrogen peroxide fuel cells (DBHPFCs). The Co sublayers, which have different structures, e.g. smooth and fiber-shaped, were used as a substrate for the depositing of Pt crystallites. The Co layer having smooth structure was deposited on the Cu surface (denoted as Co_smooth/Cu) via electroless deposition using morpholine borane as a reducing agent. Co layers, which have a fiber-shaped structure and the thickness of ~3 mm, were electroplated on the Cu surface (denoted as Co_fiber/Cu) from the electrolyte containing CoSO₄, NaOH and N-(2-Hydroxyethyl) ethylenediamine. The Pt crystallites were deposited on the Co_smooth/Cu and Co_fiber/Cu electrodes by their immersion into a Pt(IV)-containing solution at a temperature of 25^oC for different time periods. It has been determined that the Pt loadings were in the range from 10 to 14 µg_Pt cm^–2 and 5 to 29 µg_Pt cm^–2 in the PtCo_smooth/Cu and PtCo_fiber/Cu catalysts, respectively.

The activity of the prepared PtCo_smooth/Cu and PtCo_fiber/Cu catalysts for borohydride oxidation reaction (BOR) was evaluated using cyclic voltammetry and chronoamperometry. The performance of a DBHPFC operating with 1 M NaBH₄ + 4 M NaOH as fuel and 5 M H₂O₂ + 1.5 M HCl as an oxidant, while employing Pt as the cathode catalyst and PtCo_smooth/Cu and PtCo_fiber/Cu catalysts with different Pt loadings as the anodes were investigated.

It has been determined that the prepаred PtCo_smooth/Cu and PtCo_fiber/Cu cаtаlysts hаve а higher аctivity аnd а better stаbility for the oxidаtion of BH₄^- compаred to those of Co_smooth/Cu аnd Co_fiber/Cu. The аssembled direct borohydride-hydrogen peroxide fuel cell with PtCo_smooth/Cu and PtCo_fiber/Cu cаtаlysts as the anodes exhibited аn open circuit voltаge of cа. 1.9 V.

Acknowledgment

This research was funded by a grant (No. M-ERA.NET-1/2016) from the Research Council of Lithuania.