ScholarWorks@성균관대학교

초록

Defect engineering and synergistic interfaces are critical structural factors for catalytic oxidation, yet the role of a Ov-Ti3 & thorn;-Pt triadic interface remains unexplored in MXene-induced TiO2 (MTO) for formaldehyde (HCHO) oxidation. In this study, a novel Pt/MTO catalyst was synthesized by leveraging defect-controlled anatase MTO, followed by 0.1% Pt impregnation under N2/H2 annealing. Structural analysis confirmed the formation of anatase TiO2 enriched with oxygen vacancies (Ov-Ti3 & thorn;) whose concentration and distribution are tuned by the annealing atmosphere, thereby influencing crystallinity, Pt particle size, and oxidation state. Importantly, in MTO, the Ov-Ti3 & thorn;-Pt interface establishes strong, directional electronic coupling, enabling charge delocalization between Ov-Ti3+ defect states and Pt surface atoms unlike conventional oxygen-vacancy-noble-metal systems where vacancies act mainly as anchoring sites. The coexistence of Ov sites and abundance of defect-induced onsite-OH (Ov-H) groups creates a synergistic interface with Pt nanoparticles, facilitating strong electronic coupling and active site availability. In situ DRIFTS revealed that Pt sites promote O2 dissociation, while Ov-Ti3 & thorn; rich defects serve as adsorption sites for HCHO. Meanwhile, intrinsic lattice hydroxyls (OL-H) promote H2O dissociation to generate Ov-H groups which accelerate the oxidation of formate intermediate directly to CO2, bypassing the carbonate pathway. These cooperative effects-between defect-rich MTO, well-dispersed Pt, and Ov-H interfaces-reflect quantum phenomena such as electron localization-delocalization and quantum confinement, significantly boosting catalysis. Consequently, Pt/MTO-N2 achieved 98.2% HCHO removal (10 ppm) within 100 min, with steady CO2 generation at a WHSV of 150,000 cm3 & sdot;h- 1 & sdot;g_cat- 1. This work highlights a strategy for localized defect confinement and elucidates how Ov-driven structures modulate catalytic kinetics in HCHO oxidation.

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