Metal-Catalyst-Free Fuel Cells with Carbon As Catalysts

As a potential solution to sustainable energy concern, wide spread commercialization of fuel cell has long been hindered by limited reserve and relatively high cost of metal catalysts. Although there are achievements in terms of non-noble metal catalysts, it is still very challenging to replace metal catalysts at the anode side of low temperature fuel cells by non-metal catalysts, followed by achieving total removal of the metal catalysts from a fuel cell. As a carbon-only catalyst prepared by reduction of carbon monoxide with lithium oxide, 3D graphene is found to electrochemically catalyze carbohydrazide oxidation reaction efficiently. Similarly, CNT outperforms carbon black and 2D graphene in catalyzing carbohydrazide oxidation reaction. Prototypes of anode metal free and completely metal free anion exchange membrane fuel cell with 3D graphene anode catalyst generate peak power density of 75.1 mW cm^-2 and 24.9 mW cm^-2, respectively. In average, 4.9 electrons are electrochemically extracted from one carbohydrazide molecule, indicating the existence of C-N bond cleavage, which is a key factor contributing to high fuel utilization efficiency.