Cu-MOF-Derived Cu/Cu2O Nanoparticles and CuNxCy Species to Boost Oxygen Reduction Activity of Ketjenblack Carbon in Al-Air Battery

Developing a highly efficient and low-cost catalyst on a large scale is still a big challenge for fuel cells and metal-air batteries. Decorating carbon supports with some active sites (e.g., nitrogen doping, metal-nitrogen doping) seems to be a promising strategy. In this work, we first reported a Cu-centered metal organic framework (Cu-MOF) as a self-sacrificing precursor to modify the Ketjenblack (KB) carbon, where crystalline Cu/Cu2O nanoparticles and noncrystalline CuNxCy species were derived after calcination. The catalytic activity toward the oxygen reduction reaction (ORR) of this modified KB carbon was significantly boosted probably because of the synergistic effect between crystalline Cu/Cu2O nanoparticles and noncrystalline CuNxCy species. This hybrid catalyst exhibited a comparable half-wave potential (0.82 V versus reversible hydrogen electrode, RHE) and superior limiting-current density and durability to the commercial 20 wt % Pt/C. The excellent activity was also further confirmed by the application in home-made Al-air batteries, yielding a highly stable voltage of 1.53 V at a current density of 40 mA cm(-2).