Nonprecious Metal Bifunctional Catalysts for Oxygen Electrocatalysis Using a Metal-Organic Framework

Green energy devices such as Zn-air batteries require a highly active bifunctional oxygen electrocatalyst. In this study, heat-treated (HT) FeNi-alloy nanoparticles embedded on a porous carbon matrix (FeNi-MOF-HTs) are prepared by annealing Fe- and Ni-based metal-organic frameworks (MOFs). FeNi-MOF-HTs exhibit an improved oxygen catalytic performance when compared with that of the catalysts derived from Fe-only MOFs. The enhanced activities of the FeNi-MOF-HTs are attributed to their nanoscale size and an electronic interaction between Fe and Ni in the FeNi alloy. An optimized annealing temperature of 800 degrees C provides porosity and promotes graphitization of the carbon matrix in FeNi-MOF-HTs. This work describes an effective strategy for the design of highly active bifunctional electrocatalysts.