Surface-Phosphorylated Ceria for Chlorine-Tolerance Catalysis.

Area of Science:

• Catalysis
• Materials Science
• Surface Chemistry

Background:

• Understanding active sites is crucial for designing effective catalysts.
• Ceria (CeO2) based catalysts are widely studied for various catalytic applications.
• Chlorine tolerance remains a significant challenge for many catalytic processes.

Purpose of the Study:

• To computationally discover and experimentally validate a novel surface-phosphorylated ceria catalyst.
• To investigate the active site structure and reaction mechanism of the catalyst.
• To demonstrate the catalyst's performance and stability in degrading chlorinated volatile organic compounds (VOCs).

Main Methods:

• Ab initio molecular dynamics (AIMD) calculations to probe atomic behavior.
• In situ near-ambient pressure X-ray photoelectron spectroscopy (in situ NAP-XPS) for surface analysis.
• Experimental catalysis testing, including a pilot-scale test for chlorinated VOC destruction.

Main Results:

• Identification of a predominantly HPO4 active structure on CeO2 facets.
• Observation of mobile hydrogen atoms on the catalyst surface at elevated temperatures.
• Demonstration of robust chlorine tolerance and high catalytic activity for chlorinated VOC degradation.
• Sustained catalyst stability over 68 days in a pilot test.

Conclusions:

• Surface phosphorylation creates a highly active and chlorine-tolerant ceria catalyst.
• A unique hydrogen atom hopping mechanism contributes to chlorine radical quenching.
• The developed catalyst shows significant potential for industrial applications in treating chlorinated off-gases.