Pt0.25Ru0.75/N-C as Highly Active and Durable Electrocatalysts toward Alkaline Hydrogen Oxidation Reaction

A series of uniform 3.0-3.8 nm Pt1-xRux particles supported on nitrogen-doped carbon (N-C) is synthesized by wet-impregnation, high-temperature reduction, and high-temperature NH3 etching. As far as it is known, the resultant Pt0.25Ru0.75/N-C exhibits the highest activity toward alkaline hydrogen oxidation reaction (HOR) in terms of mass specific exchange current density (j(0,m), 1654 A g(PtRu)(-1)), that is 4.7 and 1.4 times of commercial Pt/C (352 A g(Pt)(-1)) and PtRu/C (1213 A g(PtRu)(-1)), respectively. The remarkable activity originates from a high electrochemical active surface area (ECSA), weakened hydrogen binding energy (HBE), and appropriate oxophilic property. Additionally, the Pt0.25Ru0.75/N-C displays much improved durability during potential cycling with respect to commercial Pt/C and commercial PtRu/C, likely arising from the stabilizing effect of nitrogen dopant of N-C on Pt0.25Ru0.75. Furthermore, the single cell fabricated with 0.08 mg(Pt) cm(-2) of the Pt0.25Ru0.75/N-C as the anode reaches a peak power density of 831 mW cm(-2), which is 1.8 and 1.1 times of that fabricated with 0.2 mg(Pt) cm(-2) of commercial Pt/C and 0.13 mg(Pt) cm(-2) of commercial PtRu/C as the anode, respectively. This study exhibits that low-platinum alkaline HOR electrocatalyst should be a highly promising approach for hydroxide exchange membrane fuel cells (HEMFCs).