Fe-N_x sites have been identified as core descriptors for Fe-N/C based oxygen reduction reaction catalysts.However, the low density and less utilization of Fe-Nxsites render these catalysts with inefficient catalytic ...Fe-N_x sites have been identified as core descriptors for Fe-N/C based oxygen reduction reaction catalysts.However, the low density and less utilization of Fe-Nxsites render these catalysts with inefficient catalytic performance. Herein, we develop an organic carboxylate-assisted engineering to construct Fe, N co-doped porous carbon interlinked carbon nanotubes(Fe/N-CCNTs) with high-density and sufficiently exposed FeNxsites based on self-catalyzed effect. The existing forms of Fe include Fe-imidazole configuration and coordination with unsaturated Zn sites via organic carboxylate as linkers, leading to high-density Fe-N_x sites after pyrolysis. Besides, hexatomic carbon rings of organic carboxylate lower cyclization energy barrier for CNT formation, resulting in CNTs interlinked with separated active sites through “active pointconductive line-active point” connections. The optimal sample(Fe-BOAc-PNC) exhibits the onset potential of 0.93 V(vs. RHE) and half-wave potential of 0.84 V in alkaline solution. The liquid-state Zn-air battery(ZAB) employing Fe-BOAc-PNC generates large power density(160 m W/cm^(2)) and stability over 160 h.Moreover, the assembled flexible ZAB displays superb power density of 93 m W/cm^(2) with robust flexibility. This work provides an insightful perspective for designing Fe-N/C catalysts with high-density and sufficiently exposed active sites for energy storage application.展开更多
基金supported by the National Natural Science Foundation of China (No. U1804255)the Key Research & Development and Promotion Projects in Henan Province (Nos. 222102520038 and 212102210651)。
文摘Fe-N_x sites have been identified as core descriptors for Fe-N/C based oxygen reduction reaction catalysts.However, the low density and less utilization of Fe-Nxsites render these catalysts with inefficient catalytic performance. Herein, we develop an organic carboxylate-assisted engineering to construct Fe, N co-doped porous carbon interlinked carbon nanotubes(Fe/N-CCNTs) with high-density and sufficiently exposed FeNxsites based on self-catalyzed effect. The existing forms of Fe include Fe-imidazole configuration and coordination with unsaturated Zn sites via organic carboxylate as linkers, leading to high-density Fe-N_x sites after pyrolysis. Besides, hexatomic carbon rings of organic carboxylate lower cyclization energy barrier for CNT formation, resulting in CNTs interlinked with separated active sites through “active pointconductive line-active point” connections. The optimal sample(Fe-BOAc-PNC) exhibits the onset potential of 0.93 V(vs. RHE) and half-wave potential of 0.84 V in alkaline solution. The liquid-state Zn-air battery(ZAB) employing Fe-BOAc-PNC generates large power density(160 m W/cm^(2)) and stability over 160 h.Moreover, the assembled flexible ZAB displays superb power density of 93 m W/cm^(2) with robust flexibility. This work provides an insightful perspective for designing Fe-N/C catalysts with high-density and sufficiently exposed active sites for energy storage application.
