PtNi alloy nanoparticles grown in situ on nitrogen doped carbon for the efficient oxygen reduction reaction.

Abstract

Currently, Pt based materials are still the most efficient oxygen reduction reaction (ORR) catalysts. However, their poor stability obstructs the commercial viability of fuel cells. To lower the reaction potential barrier and enhance the stability, we constructed alloy PtNi nanoparticles (NPs) with a Pt-rich surface supported on nitrogen-doped carbon (NC) via a simple one-step solvothermal method using easily accessible reagents. The synthesized PtNi/NC exhibits enhanced mass activity (MA), specific activity (SA), and positive onset potential compared with commercial Pt/C catalysts. Meanwhile, the half-wave potential shifted negatively to only 18 mV after 5000 cycles for PtNi/NC, indicating excellent stability. The enhanced ORR performance can be ascribed to the introduction of Ni into Pt optimizing the adsorption energy of Pt towards oxygen by adjusting the d band center of the Pt atom and stronger interaction between the metal NPs and support. Our work provides a potential synthesis strategy for developing a Pt-based catalyst with a low Pt loading and high ORR performance.