Bio-inspired micro-reactor mimicking multi-ridged mitochondrial intimae for efficient oxygen reduction

Fe3C embedded N-doped hollow rGO carbon spheres (Fe/N-HRCS) with multi -layered porous multi-ridged structure have been constructed as micro-reactors mimicking mitochondrial intimae. It is the first report on the application of a multi-layered porous hollow multi-ridged structure in oxygen reduction reaction (ORR) catalysis. Notably, the content of sacrificial template, silica nanoparticles, plays a decisive role on the micro-scopic morphology of micro-reactors. The optimal electrocatalyst, Fe/N-HRCS-1, exhibits a remarkable catalytic performance toward ORR with the onset potential of 1.03 V and half-wave potential of 0.88 V, which are comparable to that of commercial Pt/C. Such an extraordinary activity can be attributed to the synergistic effect between Fe3C nanoparticles embedded N-doped rGO layers and the distinctive bio-inspired structure. Moreover, the Fe/N-HRCS-1 catalyst also possesses superior methanol tolerance and durability, and thus holds a good promise for practical application. This work demonstrates a good example to design nature-inspired structures for high-efficiency non-noble metal electrocatalysts.