Abstract
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 ℃) 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.
Original language | English |
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Article number | 122179 |
Journal | Applied Catalysis B: Environmental |
Volume | 323 |
DOIs | |
State | Published - Apr 2023 |
Bibliographical note
Publisher Copyright:© 2022 Elsevier B.V.
Keywords
- Grand canonical reaction kinetics
- Graphitized carbon
- PEMFCs
- Pyrrolic-N
- Real-time degradation analysis