Integrated Three-Dimensional Carbon Nanopolyhedron/Metal Sulfides: An Efficient Electrocatalyst Toward Oxygen Reduction Reaction

Abstract

Carbon-based materials hybridized with metal sulfides have gained growing attention as catalytic materials for oxygen reduction reaction (ORR) due to their synergistic effects in terms of richer structural features and higher electrochemical activities. Here, a series of Zn/Co/Fe-based metal-organic frameworks (MOFs) as the precursors, which can be adopted as efficient ORR catalysts, were synthesized through a sulfuration–calcination treatment. The effects of precursor composition, heteroatom doping, and pyrolysis temperature on the structure and electrochemical performance of the catalysts were discussed in detail. It is found that well-grown carbon nanotubes (CNTs) on the surface of graphitic carbon matrix are formed under the synergy effect of trimetallic-based species during pyrolysis. Benefiting from the three-dimensional unique structure with appropriate dopants and high porosity, the catalyst derived from the optimized Zn/Co/Fe-MOFs achieves a half-wave potential of 0.87 V in an alkaline medium for ORR, which is comparable with commercial electrocatalysts. In addition, an outstanding ORR durability of the proposed catalyst in alkaline media was also demonstrated. This work highlights the potential to rationally design and fabricate high-performance ORR catalysts for commercialization.