PtNi supported on binary metal oxides: Potential bifunctional electrocatalysts for low-temperature fuel cells?

Abstract

PtNi nanoparticles (NPs) were synthesised by microwave irradiation technique and supported onto Mn 2 O 3 and two binary metal oxides, Mn 2 O 3 -TiO 2 and Mn 2 O 3 -NiO, prepared by solid-state dispersion method. TEM analysis revealed formation of PtNi NPs of 2–3 nm diameter on the metal oxides. Their activity for oxygen reduction reaction (ORR) and borohydride oxidation reaction (BOR) in alkaline media was studied using voltammetric, amperometric and electrochemical impedance spectroscopy techniques. The effect of electrolyte composition and operation temperature on the catalysts performance was also examined. ORR and BOR kinetic parameters, namely Tafel slope, kinetic current density, order of reaction and activation energy were evaluated, enabling direct comparison of the three electrocatalysts performance. The results show that PtNi NPs anchored on binary metal oxide supports possess superior activity for BOR in alkaline media, suggesting their potential application as anodes in low-temperature fuel cells.