Nanoscale Pt5Ni36 design and synthesis for efficient oxygen reduction reaction in proton exchange membrane fuel cells

Abstract

Pt-based alloys are currently one of the most popular choices for high-performance ORR catalysts in PEMFCs. However, they often require multi-step synthesis or cumbersome intermediate treatment processes and high-temperature annealing steps. Herein, we introduce a facile and ultrafast carbothermal shock (CTS) method for the synthesis of carbon nanofiber supported bimetallic PtNi nanoparticles with a Pt : Ni ratio of 1 : 7.2 (Pt₅Ni₃₆/CNFs). Comprehensive theoretical studies combined with experimental studies verified that carbon metabolism is the synthesis mechanism of Pt₅Ni₃₆/CNFs. As expected, Pt₅Ni₃₆/CNFs delivered superior oxygen reduction reaction (ORR) catalytic performance with a half-wave potential of 0.86 V, which is 30 mV superior to that of commercial Pt/C (20% of Pt) in an acidic solution. When applied as a cathode material in a PEMFC, Pt₅Ni₃₆/CNFs exhibited a high power density of 1.092 W cm⁻², displaying an excellent Pt utilization of 0.118 g_Pt kW⁻¹ and acceptable stability with almost no loss of working current after 30 h in H₂/O₂ single-cell operation. Our work provided new insight into the simple, rapid, and environment-friendly synthesis of superb active Pt-based catalysts for electrocatalysis and other applications.