Co-Fe Alloy/N-Doped Carbon Hollow Spheres Derived from Dual Metal-Organic Frameworks for Enhanced Electrocatalytic Oxygen Reduction.

Metal-organic framework (MOF) composites have recently been considered as promising precursors to derive advanced metal/carbon-based materials for various energy-related applications. Here, a dual-MOF-assisted pyrolysis approach is developed to synthesize Co-Fe alloy@N-doped carbon hollow spheres. Novel core-shell architectures consisting of polystyrene cores and Co-based MOF composite shells encapsulated with discrete Fe-based MOF nanocrystallites are first synthesized, followed by a thermal treatment to prepare hollow composite materials composed of Co-Fe alloy nanoparticles homogeneously distributed in porous N-doped carbon nanoshells. Benefitting from the unique structure and composition, the as-derived Co-Fe alloy@N-doped carbon hollow spheres exhibit enhanced electrocatalytic performance for oxygen reduction reaction. The present approach expands the toolbox for design and preparation of advanced MOF-derived functional materials for diverse applications.