Size and structure tuning of FePt nanoparticles on hollow mesoporous carbon spheres as efficient catalysts for oxygen reduction reaction

Finding and designing cathode oxygen reduction reaction(ORR) catalysts with high activity and stability in acidic electrolyte is essential for the large-scale application of fuel cells and metal-air batteries.Pt-based alloys have emerged as potential electrocatalysts for the oxygen reduction reaction.Herein,we adapted a simple pyrolytic reduction method to grow FePt nanoalloys on hollow mesoporous carbon supports.Benefiting from the ultra-high specific surface of the hollow mesoporous carbon,the in situ formed FePt NPs were homogenously deposited on the carbon supports with size smaller than5 nm.The optimized FePt-HMCS showed a remarkably increased mass activity(MA) of 0.582 A·mg^(-1)_(Pt) at 0.75 V in ORR,being 6.3 times higher than that of commercial Pt/C(0.093 A·mg^(-1)_(Pt)).Meanwhile,the FePt NPs showed negligible decay in mass activity with 21 mV of negative shift in the half-wave potential after 5000 electrochemical cycles,which is more stable than that of commercial Pt/C(6.6% decay in MA with 30 mV of negative shift).The study demonstrated a simple strategy for controlling the alloy size with enhanced metal-support interactions to boost their promising application in fuel cells.