Metal organic framework for the fabrication of mutually interacted Pt[sbnd]CeO2[sbnd]C ternary nanostructure: advanced electrocatalyst for oxygen reduction reaction

Abstract

Metal nanoclusters have attracted increasing attentions due to their extremely high catalytic activities. However, how to keep their structural and catalytic stabilities is still a challenge, especially in electrocatalysis. Herein, a novel mutual-interacted PtCeO2C ternary nanostructure was designed and fabricated from Ce-based metal organic framework (Ce-MOF). In this unique nanostructure, through a calcination process, abundant tiny CeO2 nanoclusters (∼2 nm) can be produced from the Ce-MOF itself and they are uniformly inserted in the MOF-derived porous carbon matrix. Meanwhile, the following deposited surfactant-free Pt nanoclusters (∼2 nm) contact well with both carbon and CeO2 nanoclusters. The electrocatalytic activity of the PtCeO2C ternary nanostructure for the oxygen reduction reaction (ORR) was investigated. With such ternary structure, the interacted CeO2 and Pt nanoclusters showed high stability. Moreover, the CeO2 can modify the electronic density of Pt and enhance the interaction between Pt and carbon at the PtCeO2 interface. Meanwhile, with the mutual interaction, the corrosion resistance of carbon can be improved at the CeO2C interface, and the conductivity of the catalyst can be improved with the carbon framework. With these structure advantages, the Ce-MOF-derived catalyst exhibited higher electrocatalytic performance than commercial PtC for ORR with more positive half-wave potential and higher limiting diffusion current density. The origin of the enhanced ORR performance was further disclosed by X-ray absorption fine spectroscopy (XAFS) characterization.