Tuning the degradation activity and pathways of chlorinated organic pollutants over CeO2 catalyst with acid sites: synergistic effect of Lewis and Bronsted acid sites

Enhancing the surface acidity has been seen as an effective strategy to optimize the performance of catalysts for the degradation of chlorinated volatile organic compounds (CVOCs). Herein, a series of catalysts are constructed by introducing Lewis and Bronsted acid sites into the skeleton surface of three-dimensional ordered macroporous (3DOM) CeO2. By a systematic study, we find that the introduction of Lewis acid sites can enhance the redox capacity of CeO2, while the surface Bronsted acid sites of the material promote chlorobenzene (CB) degradation through hydrolysis that is an effective degradation route to generate less chlorinated organic by-products. The optimal S-Ce0.7Zr0.3O2 with both abundant surface Lewis and Bronsted acid sites presents a stable activity and only 1.2% Cl-2 selectivity with similar to 90% CB conversion at 410 degrees C for 24 h. This work reveals the different roles and synergistic effects of Lewis and Bronsted acid sites to develop environmentally friendly CVOC combustion catalysts.

Automated summary

The introduction of Lewis acid sites enhances the redox capacity of CeO2, while surface Bronsted acid sites promote the hydrolysis degradation of chlorobenzene (CB). The optimal catalyst, S-Ce0.7Zr0.3O2, with abundant surface Lewis and Bronsted acid sites, shows stable activity with low chlorine by-product selectivity and high CB conversion.