Tellurium-Nitrogen-Carbon Support Boosting Platinum Catalysis in High-Efficiency Proton Exchange Membrane Fuel Cells

Enhancing the energy conversion efficiency of fuel cells necessitates optimization of oxygen reduction reaction (ORR) under high-voltage conditions through improved Pt catalysis. This study introduces an electrocatalyst that uniformly anchors a high loading (40 wt%) of small Pt nanoparticles (3.2 nm) on a novel support: tellurium and nitrogen co-mediated graphitized mesoporous carbon (Te-N-GMC). The strong metal-support interactions arise from Pt─Te and Pt─N bonds. Density functional theory (DFT) calculations and operando X-ray absorption spectroscopy reveal that Te-N co-mediation enhances the high-voltage oxidation resistance of Pt via electron reverse transfer from the Te-N-GMC support to Pt. Consequently, the Pt valence state in Pt/Te-N-GMC increases by only +0.085 from open-circuit potential to 1.5 V, resulting in exceptional durability over 100 000 high-voltage cycles (1-1.5 V) with negligible morphological aggregation. Moreover, the Te-N-GMC support effectively lowers the energy barrier of the rate-determining step, enabling Pt/Te-N-GMC to achieve outstanding activity (0.7 V at 1.26 A cm^-2 under H₂-air conditions). This translates to an 18.6% increase in electrical efficiency compared with commercial Pt/C at the same output power density. These findings demonstrate the potential of Te-N-GMC as a robust cocatalyst for high-voltage ORR and highlight a promising strategy for enhancing Pt catalysis for high-efficiency fuel cells.