New copper/GO based material as an efficient oxygen reduction catalyst in an alkaline medium: The role of unique Cu/rGO architecture

A new hybrid Cu/rGO catalyst obtained by a thermal treatment of the composite of a copperbased MOF with graphite oxide exhibited a marked catalytic activity for oxygen reduction reaction (ORR) in an alkaline medium, high tolerance to methanol oxidation and superior long-term stability over 20 hours. The unique architecture of the copper atoms in the 3D framework of the pristine MOF coupled with the excellent electron transfer properties of rGO lead to materials with a homogenous distribution of copper nanoparticles of specific chemistry assembled within the graphene sheets. Fast O2 adsorption and charge transfer owing to the strong interactions between copper atoms and graphite oxide resulted in highly stable and active Cu/rGO electrodes, compared to the carbonized MOF. The synergistic effect of copper and rGO in the composite leads to a superior ORR activity in terms of long-term stability and high current densities, close to the best performance reported for Pt and other metal-free electrocatalysts.