Nanoporous PtFe Nanoparticles Supported on N-Doped Porous Carbon Sheets Derived from Metal–Organic Frameworks as Highly Efficient and Durable Oxygen Reduction Reaction Catalysts

Abstract

Designing and exploring catalysts with high activity and stability for oxygen reduction reaction (ORR) at the cathode in acidic environments is imperative for the industrialization of proton exchange membrane fuel cells (PEMFCs). Theoretical calculations and experiments have demonstrated that alloying Pt with a transition metal can not only cut down the usage of scarce Pt metal but also improve performance of mass activity compared with pure Pt. Herein, we exhibit the preparation of nanoporous PtFe nanoparticles (np-PtFe NPs) supported on N-doped porous carbon sheets (NPCS) via facile in situ thermolysis of a Pt-modified Fe-based metal-organic framework (MOF). The np-PtFe/NPCS exhibit a more positive half-wave potential (0.92 V) compared with commercial Pt/C catalyst (0.883 V). The nanoporous structure allows our catalyst to possess high mass activity, which is found to be 0.533 A·mg_Pt^-1 and 3.04 times better than that of Pt/C (0.175 A·mg_Pt^-1). Moreover, the conversion of PtFe NPs from porous to hollow structure can maintain the activity of electrocatalyst. Our strategy provides a facile design and synthesis process of noble-transition metal alloy electrocatalysts via noble metal modified MOFs as precursors.