Core-shell MOF-derived Fe3C-Co-NC as high-performance ORR/OER bifunctional catalyst
Huaqi Wang, Chenghong Sun, Enze Zhu, Chaoyang Shi, Jie Yu, Mingli Xu
Abstract
Metal–organic framework (MOF)-derived carbon materials have emerged as important candidates in the field of catalysis because of their simple synthesis, easy construction, good conductivity, and high catalytic activity. Fe 3 C nanoparticles prepared from MOFs facilitate the catalytic activity of adjacent single atoms and exhibit powerful catalytic properties. In this work, a composite structured catalyst with Fe 3 C, Co nanoparticles , and M-N x single atoms (M = Co, Fe) was synthesized (denoted as Fe 3 C-Co-NC) by constructing Fe-doped bilayer zeolitic imidazolate frameworks (ZIFs) with a core–shell structure, which were used as bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The Fe 3 C-Co-NC catalyst exhibits superior half-wave potential ( E 1/2 = 0.89 V) and overpotential ( E j=10 = 1.67 V) and outperforms the commercial Pt/C and RuO 2 . This result can be attributed to the high specific surface area , hierarchical pore structure , and high graphitization degree of the Fe 3 C-Co-NC catalyst, especially the synergistic effect between Fe 3 C and adjacent single-atom active sites. Specifically, the Zn–air battery assembled using the Fe 3 C-Co-NC catalyst displays high peak power density (203 mW cm −2 ) and specific capacity (815 mAh g −1 ) without degradation after charge/discharge cycles for 57 h. Therefore, this work offers important insights into the design and research of high-performance ORR/OER bifunctional catalysts .