Thermostable Tellurium Anchoring Enabling Robust Thermal and Electrochemical Stability for Pt3Co Intermetallic Fuel Cell Catalysts

Abstract Highly active Pt‐based intermetallic nanoparticles (i‐NPs) loaded on stable supports have garnered considerable interest as promising oxygen reduction reaction (ORR) catalysts for proton‐exchange‐membrane fuel cells (PEMFCs). Herein, thermostable tellurium (Te) is vapor‐deposited onto commercial conductive carbon to anchor high‐temperature‐synthesized Pt 3 Co i‐NPs. Advanced characterization and density functional theory (DFT) calculations demonstrate that the binding energy of Pt 4f and Co 2p shift positively by 0.12 and 0.95 eV after the introduction of Te in carbon support, promoting the formation of Pt─Te bonds, which enhances the metal–support interactions (MSIs) in Pt 3 Co/Te‐C (with a more negative binding energy of −10.28 eV). The average size of well‐dispersed Pt 3 Co i‐NPs (≈3.9 nm) on Te─C is considerably smaller than that of Pt 3 Co i‐NPs (≈9.1 nm) on commercial carbon. The specific activity of Pt 3 Co/Te‐C decreases by only 1.5% after 100,000 ultra‐long voltage‐accelerated cycles, while the morphology remains almost unchanged. The membrane electrode assembly using Pt 3 Co/Te‐C as a cathode demonstrates impressive activity (power density of 2.32 W cm −2 @4 A cm −2 and mass activity of 0.50 A mg Pt −1 @0.9 V) and robust durability (mass activity@0.9 V loss of 26% after 30,000 cycles with intact L1 2 ordered structure) in H 2 –O 2 operation, significantly exceeding the DOE 2025 requirements.