Activity-stability benefits of Pt/C fuel cell electrocatalysts prepared via remote CeO2 interfacial doping

Abstract

Ceria coated carbon nanotubes (CeO2@CNTs) were prepared as a versatile support material to improve both the activity and stability of platinum (Pt)-based catalysts. We demonstrated that the CeO2 nanoparticles (NPs) had an extrinsically remote functionalization effect on the Pt electrocatalysis. The CeO2 modulated the electronic structure, and facilitated the O2 adsorption property of Pt without any intrinsic chemical doping or Pt-alloying. This led to d-band electron filling in Pt, and delivery of active oxygens (O-) to the Pt surface via oxygen spillover at the Pt-CeOx interface, thus enhancing the ORR activity. Furthermore, due to the unique redox behavior between Ce3+ and Ce4+, the dissolved Ce ions could also participate in the radical scavenge reaction, which prevents the chemical degradation of polymeric components in the cell. A single cell using the Pt NPs supported on CeO2@CNT as a cathode catalyst delivered a superior electrochemical performance and a retained durability compared to the cells with pristine CNT supported Pt NPs.