Wrinkled single-layer Ti3C2TX MXene as a superior support for platinum nanoparticles enabling ultra-high oxygen reduction activity

The emergence of Ti 3 C 2 T X as a novel two-dimensional transition metal carbide catalyst support has sparked widespread research interest due to its high electrical conductivity and tunable surface chemistry. To address the inherent interlayer stacking limitations of conventional Ti 3 C 2 T X , the single-layer Ti 3 C 2 T X (SL-Ti 3 C 2 T X ) support was prepared via selective etching of aluminum from bulk Ti 3 AlC 2 , followed by liquid-phase exfoliation of multilayered Ti 3 C 2 T X into nanosheets. Subsequently, a high-performance Pt/SL-Ti 3 C 2 T X composite electrocatalyst was synthesized by in situ reducing Pt 2+ into Pt nanoparticles (Pt NPs) through an ethylene glycol-mediated reduction method. Electron microscopy analyses demonstrated that Pt NPs (~2.89 nm size) uniformly loaded on the wrinkled surface of SL-Ti 3 C 2 T X nanosheets with thickness of 1.5 nm. Raman spectrum analysis revealed the functionalization of the support SL-Ti 3 C 2 T X (T X : O, -OH and F), while the strong metal-support interaction (SMSI) between Pt NPs and SL-Ti 3 C 2 T X was indicated through XPS patterns of the sample. With an electrochemical active surface area (ECSA) of 176 m 2 ·g −1 and a half-wave potential (E 1/2 ) of 0.874 V, the produced composite catalyst outperformed Pt‑carbon (Pt/C) catalyst in acidic electrolytes in terms of oxygen reduction reaction (ORR) performance. After undergoing 30,000 cycles of accelerated durability testing (ADT), the Pt/SL-Ti 3 C 2 T X catalyst maintained 77% of its initial activity, with a mass activity loss of only 22%, while the corresponding data for Pt/C are 51% and 48%, respectively. Based on its unique advantages including the single-layer structure and surface functionalization, SL-Ti 3 C 2 T X could be used as a high-performance catalyst support to produce highly active and stable electrocatalysts for ORR in energy conversion field.