Low temperature synthesis of new highly graphitized N-doped carbon for Pt fuel cell supports, satisfying DOE 2025 durability standards for both catalyst and support

For polymer electrolyte membrane fuel cells (PEMFCs), the state-of-the-art electrocatalysts are based on carbon -supported Pt group metals. However, current carbon supports suffer from carbon corrosion during repeated start -stop operations, causing performance degradation. We report a new strategy to produce highly graphitized carbon with controllable N-doping that uses low-temperature synthesis (650 celcius) from g-C3N4 carbon-nitrogen precursor with pyrolysis using Mg. The high graphiticity is confirmed by high-intensity 2D Raman peak with low ID/IG (0.57), pronounced graphitic XRD planes, and excellent conductivity. Without further post-treatment, this highly graphitized N-doped carbon (HGNC) material combines high pyrrolic-N content with high porosity. Supporting Pt on HGNC exhibits excellent oxygen reduction activity for PEMFC with greatly improved durability as proved by real-time loss measurements of Pt and carbon, the first to surpass the DOE 2025 durability targets for both catalyst and support. The Pt/HGNC-65 shows 32% and 24% drop in mass activity after accelerated durability tests of both electrocatalyst and support, respectively, which are less than DOE target of 40% loss. The atomistic basis for this durability is explained via quantum mechanics-based molecular dynamics simulations. Interestingly, it is found that pyrrolic-N strongly interacts with Pt, making the Pt catalyst more stable during fuel cell reaction.

Automated summary

This study presents a new strategy to produce highly graphitized N-doped carbon materials with excellent conductivity and oxygen reduction activity for polymer electrolyte membrane fuel cells. The durability and stability of the material are greatly improved, surpassing the DOE 2025 targets. The strong interaction between pyrrolic-N and Pt is found to enhance the stability of the Pt catalyst during fuel cell reactions.