Catalytic Advancements in NH3 Selective Catalytic Oxidation: The Impact of Cu-Induced Lattice Distortion in TiO2 Crystal structure.

Abstract

A series of xCu -TiO2 obtained from the sol-gel method were tested for NH3 selective catalytic oxidation (NH3-SCO). Its performance was higher than that of supported Cu/TiO2-Im and solvent-free Cu/TiO2-SF. The catalyst exhibits better water resistance at 300 ℃. XRD, Raman, and H2-TPR proved that the crystal lattice of TiO2 was deformed by Cu doping, which increased the specific surface area of the catalyst. The dispersion of the Cu component is further enhanced. The enhancement of redox potential was the key to improving catalytic activity. The NH3-TPD results prove that more acidic sites promote more active NH3 species being adsorbed and dissociated on the catalyst surface. The in-situ DRIFTs results certify that the NH3 species adsorbed on the Lewis acid sites were easier to consume than those on the Brønsted acid sites. The DFT theoretical calculation demonstrates that the doped Cu promotes the TiO2 conduction band to move closer to the Fermi level and enhances the redox performance of the catalyst. The results suggest that the Cu-TiO2 catalyst was a potential catalyst under actual working conditions, which would provide a technological reserve for the development and diffusion of ammonia slip for both mobile and fixed sources.