High efficiency N/C foam supported Pd electrode for direct sodium borohydride-hydrogen peroxide fuel cell

Abstract

A bi-functional electrode material of self-supporting N-doped C foam grown Pd nanoparticles (Pd@N/C-8 foam) for NaBH4 electrooxidation and H2O2 reduction reaction is successfully prepared. The Pd@N/C-8 foam electrode is fabricated by sacrificial template synthesis of N/C foam followed by 8 repetitive Pd impregnation reduction cycles. The Pd@N/C-8 foam electrode exhibits an extraordinary catalytic performance (642 mA cm−2 at −0.2 V) in 2 mol L−1 NaOH and 0.3 mol L−1 NaBH4, which is due to the large electrochemical active surface area, low activation energy (Ea = 10.34 kJ mol−1) and 60.83% utilization efficiency of NaBH4. Besides, its catalytic density for H2O2 electroreduction reaches 648 mA cm−2 at −0.2 V in 2 mol L−1 H2SO4 +1.3 mol L−1 H2O2. The kinetic parameters show that the electrooxidation of BH4− and the electroreduction of H2O2 on Pd@N/C-8 foam electrode are first-order reactions, and the number of transferred electrons are 5.8 and 1.56, respectively. Further exploration of Pd@N/C-8 foam electrode on the direct sodium borohydride-hydrogen peroxide fuel cell (DBHPFC) displays the maximum power density of 137 mW cm−2 and a superior stability. In view of the excellent performance, Pd@N/C foam will be a highly efficient electrode material of DBHPFC.