The electrochemical properties of a lithium air secondary battery (LAB) cell incorporating CMK-3 or carbon replica (CR) as a highly ordered mesoporous carbon support material were examined under the condition of a current density of 0.1 mA/cm2 with a voltage range of 2.0 to 4.2 V in a dry air atmosphere. The first discharge capacities of the LAB cell incorporating Pt10Ru90 electrocatalyst/CMK-3 and CR were 103 and 1000 mAh/g, respectively. The cycle properties of the LAB cell incorporating Pt10Ru90 electrocatalyst/CMK-3 was poor; in contrast, the one incorporating CR showed better cycle stability (828 mAh/g up to 9 cycles). These superior properties with CR are due to its larger surface area and larger total pore volume than those of CMK-3.
It is a big challenge to explore strategies for efficiently utilizing the excellent co-catalytic elements such as Au and Ru in single electrocatalyst to enhance the kinetics of formic acid oxidation reaction (FOR) on Pt-based electrocatalysts. Herein, a novel ternary PtRu-Au/C catalyst with Au nanoparticles and PtRu alloy nanoparticles is designed for FOR. The PtRu-Au/C catalyst is facilely synthesized by self-assembly method and exhibits 13 and 5 times higher specific activity for formic acid electrooxidation than Pt/C and PtRu/C, which is ascribed to the synergy of kinetics acceleration by Au nanoparticles and enhanced poisoning tolerance resulting from Ru element.