Study on the characteristics of zeolite-promoted thermal decomposition of HO for efficient NO oxidation.

The HO evaporation rate directly affected the oxidation of NO by HO. Green zeolite and synthetic mordenite were selected to promote HO thermal decomposition and NO oxidation. The effects of different zeolites, evaporation conditions, temperatures, and reactant concentrations on the NO oxidation ratio were explored. The promotion mechanism of zeolite on NO oxidation by HO thermal decomposition was explained. The results show that the zeolite surface can significantly accelerate the HO evaporation rate to obtain a high NO oxidation ratio. The hydrophilicity and rich pore structure of zeolite enable the rapid diffusion and evaporation of droplets on the zeolite surface. Compared with the green zeolite with the mesoporous structure, the synthetic mordenite with the hierarchical pore structure has a more obvious promotion effect on the NO oxidation by HO thermal decomposition. The reason is that the synthetic mordenite contains micropores, resulting in a larger specific surface area, and the mesoporous structure is conducive to the mass transfer and diffusion of HO on its surface. The product of NO oxidation is mainly NO, which proves that ·OH plays a major role in the process.