Extraordinary activity of mesoporous carbon supported Ru toward the hydrogen oxidation reaction in alkaline media

Abstract

Hydrogen oxidation reaction (HOR), as the anode reaction in alkaline polymer electrolyte fuel cells (APEFCs), is kinetically much more sluggish than that in the proton exchange membrane fuel cell (PEMFC). Therefore, developing efficient non-platinum or even non-noble metal HOR electro-catalysts is of great significance. Herein, the carbon support (Meso C) with mesoporous ravine-like channel and corresponding Ru-loaded catalyst (Ru/Meso C) is deliberately designed to explore the effect of porous microstructure on the HOR electro-catalysis. Both the electrochemical and fuel cell tests manifests that the Ru/Meso C achieves a superior electro-catalytic performance toward the HOR with a peak power density of 1.02 W cm−2. The Cu-UPD and CO-stripping methods are creatively coupled to probe the underlying mechanism of Ru/Meso C. It is proposed that the holey microstructure is relatively hydrophobic to favor H2 access, and the mesoporous channel can provide a confined environment to protect the Ru NPs from oxidation, both facilitating the adsorption and dissociation of H2 and synergistically boosting the HOR. Therefore, to engineer porous microstructure is proved to be a feasible pathway to design efficient HOR electro-catalysts. Meanwhile, the electrochemical techniques (Cu-UPD & CO-stripping) may act as a potential tool to probe the hydrophilic-hydrophobic properties.