Zn/Fe Nanoparticles Co-embedded with Carbon Nanotubes Improve the Oxygen Reduction Reaction Performance

The development of low-cost, highly stable, and catalytically active oxygen reduction reaction (ORR) non-precious metal catalysts is essential for fuel cells and metal-air batteries applications. In this study, the one-step synthesis of composite catalysts of ZnFe nanoparticles embedded with nitrogen and sulfur doped carbon nanotubes (ZnS-FeS-Fe₃C/S, NCNT) was reported using ZIF-8 as precursor. The sample of ZFF/S, NCNT-8 after the optimal calcination temperature was determined by electrochemical tests to be onset potential of 0.99 V vs. RHE and a half-wave potential of 0.84 V vs. RHE, as well as a good methanol tolerance and long-term durability comparable to commercial Pt/C. It is also proposed that S, N co-doped carbon nanotube (CNT) and additional ZnS, FeS and Fe₃C providing active sites can enhance the ORR catalytic performance. The in-situ growth CNT method used in the study can provide ideas for the preparation of cathode catalysts for fuel cells and metal-air batteries.