Phosphorus-Doped Highly Crystalline Carbon for High Platinum Stability and Robust Support in Proton-Exchange Membrane Fuel Cells

Proton-exchange membrane fuel cells (PEMFCs) require durable and efficient catalyst supports to overcome the limitations of Pt-based catalysts and conventional low-crystalline carbon (LCC) supports, such as high cost, susceptibility to corrosion, and poor electrochemical durability. While highly crystalline carbon (HCC) offers improved stability, its intrinsic hydrophobicity and low defect density hinder Pt nanoparticles (NPs) nucleation and dispersion. In this study, a spin-on-dopant (SOD) approach is employed to synthesize phosphorus-incorporated HCC (HCC_P) providing stable anchoring sites that facilitate uniform Pt NPs distribution. Compared to commercial Pt/LCC, Pt/HCC_P exhibits enhanced thermal stability and oxidation resistance, with an oxidation onset temperature ≈90 °C higher. Accelerated durability tests reveal only a 2 mV half-wave potential shift and a minimal electrochemical surface area (ECSA) loss of 1.9% after 20 000 cycles, significantly lower than the 47.1% ECSA loss observed for Pt/LCC. Single-cell tests further confirm that Pt/HCC_P retains 92.4% of its initial power density, outperforming Pt/LCC. The incorporation of phosphorus improves Pt NPs stabilization on the superhydrophobic HCC surface, enhancing Pt utilization and long-term durability. This study provides valuable insights into the development of high-performance carbon supports for PEMFC catalysts.