Enhancing the Stability of Pt/Carbon with Ti3C2 MXene-Derived TiO2 for the Oxygen Reduction Reaction in Acidic Media

Abstract

Platinum on carbon remains the proton-exchange membrane fuel cell cathode state-of-the-art catalyst; however, durability losses tied to support corrosion and Pt coarsening hinder this catalyst. This study investigates utilizing different variations of Vulcan XC-72 and Ti3C2 MXene to improve the oxygen-reduction ORR activity and stability. Material characterization results provide in-depth knowledge of the Pt, carbon, and MXene composites. X-ray photoelectron spectroscopy of the synthesized samples shows that the Ti3C2 has been oxidized, and high-resolution transmission electron microscopy further reveals that the Pt(111) fringes are present with local anatase TiO2 derived from Ti3C2 MXene, which is also confirmed by X-ray microscopy, indicating that the active support is a Ti3C2-derived TiO2/carbon support. After a U.S. Department of Energy-derived accelerated stress test (AST), the Pt/75%C+25%Ti3C2 catalyst outperforms an in-house-made Pt/C prepared by the same method. This improvement is accompanied by reduced Pt particle growth after the AST for the Pt/75%C+25%Ti3C2 when compared to the Pt/C, which is attributed to stabilization of Pt at the MXene-derived anatase surface through Pt–O–Ti bonds, consistent with interfacial anchoring, together with the greater corrosion resistance of the oxide, in a composition that retains sufficient carbon for electronic percolation and gas transport. This study is the first coupled cathode half-cell performance and potential-cycling durability testing for MXene-derived composites benchmarked against Pt/C and provides vital information on material discovery utilizing MXenes for the ORR.