Fabrication of Pt nanoparticles encapsulated by N, P co-doped carbon via solution plasma for the oxygen reduction reaction

Abstract

The oxygen reduction reaction (ORR) remains a performance-limiting step in fuel cells due to sluggish kinetics and the high cost of platinum-based catalysts. In this study, we report the synthesis of nitrogen and phosphorus co-doped carbon (NPC) encapsulating Pt nanoparticles via a solution plasma process, aiming to reduce Pt usage while enhancing catalyst activity and durability. Structural characterization confirmed a core–shell morphology, with Pt cores uniformly embedded in a conductive, heteroatom-doped carbon shell. X-ray photoelectron spectroscopy revealed active nitrogen species (pyridinic and graphitic N) and P-doping contributing to electron redistribution and active site formation. Electrochemical tests in alkaline media demonstrated that the resulting NPC@Pt catalyst exhibits superior ORR activity, with a four-electron transfer pathway, higher limiting current density, and significantly improved long-term stability compared to commercial Pt/C. These findings highlight the synergy of heteroatom doping and core–shell structuring in advancing cost-effective, durable ORR electrocatalysts for alkaline fuel cells.