Hollow core-shell structured TS-1@S-1 as an efficient catalyst for alkene epoxidation.

Area of Science:

• Materials Science
• Catalysis
• Zeolite Chemistry

Background:

• Titanium silicalite-1 (TS-1) is a key catalyst for alkene epoxidation.
• Improving TS-1's catalytic activity and stability remains a significant challenge.
• Hollow nanostructures offer unique advantages in catalysis due to high surface area and diffusion properties.

Purpose of the Study:

• To synthesize and characterize a novel hollow core-shell TS-1@S-1 zeolite (HCS-TS) for the first time.
• To investigate the origin of enhanced catalytic activity in the HCS-TS material.
• To elucidate the formation mechanism of the superior active sites within the HCS-TS structure.

Main Methods:

• Synthesis of hollow core-shell TS-1@S-1 zeolites.
• Characterization using TEM, UV-vis, UV-Raman, pyridine-IR, and solid-state MAS NMR, XPS.
• Catalytic testing for alkene epoxidation.

Main Results:

• Successful preparation of hollow core-shell structured TS-1@S-1 zeolite (HCS-TS).
• HCS-TS exhibited excellent activity in alkene epoxidation.
• Superior active sites, including defective Ti(OSi)3(OH) and six-coordinated titanium species, were identified as key to improved performance.
• A synergistic effect between TPAOH and TEOS in the synthesis process was observed.

Conclusions:

• The hollow core-shell TS-1@S-1 zeolite structure significantly enhances catalytic performance in alkene epoxidation.
• Defective Ti(OSi)3(OH) and six-coordinated titanium species are crucial for the improved activity.
• The developed synthesis strategy is effective for enhancing TS-1 performance and is scalable for industrial production.