Simultaneously activating molecular oxygen and surface lattice oxygen on Pt/TiO₂ for low-temperature CO oxidation

Area of Science:

• Heterogeneous Catalysis
• Materials Science
• Surface Chemistry

Background:

• High-performance platinum (Pt)-based catalysts with low Pt loading are essential for efficient carbon monoxide (CO) oxidation, particularly at temperatures below 100°C.
• Developing such catalysts presents significant challenges due to issues like competitive adsorption and limited active sites.

Purpose of the Study:

• To design and synthesize a novel Pt-based catalyst with ultra-low Pt loading for enhanced CO oxidation.
• To investigate the catalytic mechanism and understand the role of specific structural components in low-temperature CO oxidation.

Main Methods:

• Synthesis of a Pt-based catalyst featuring Pt-Ti intermetallic single-atom alloy (ISAA) and Pt nanoparticles (NP) co-supported on a defective TiO2 support.
• Characterization of the catalyst's structure and composition.
• Evaluation of catalytic performance for CO oxidation at low temperatures, including turnover frequency (TOF) and conversion rates.

Main Results:

• Achieved a record high turnover frequency of 11.59 s⁻¹ at 80°C with only 0.15 wt% Pt loading.
• Demonstrated complete CO conversion at 120°C.
• The coexistence of Pt-Ti ISAA and Pt NP significantly improved O2 activation and alleviated competitive adsorption of CO and O2.

Conclusions:

• The synergistic effect between Pt-Ti ISAA and Pt NP on defective TiO2 is highly effective for low-temperature CO oxidation.
• Pt single atom sites stabilized by Pt-Ti ISAA induce TiO2 lattice distortion, activating lattice oxygen and enabling dual reaction pathways (Mars-van Krevelen and Langmuir-Hinshelwood) for superior catalytic activity.