Enhanced selective catalytic oxidation of triethylamine by VOx-modified CuO@TiO2 catalyst through increased amount of Lewis acid sites and adsorbed oxygen species on catalyst surface

The selective catalytic oxidation (SCO) of nitrogenous volatile organic compounds (NVOCs) has recently garnered significant attention. However, the SCO processes for tertiary amines (such as triethylamine) have not been reported. The impact of vanadium doping in CuO@TiO2 and Cu loading on SCO of TEA to N2 was investigated in this study. The surface acidity of the catalyst is primarily influenced by the VOx doping, as indicated by the results of NH3-TPD and pyridine-IR. Additionally, XPS and H2-TPR results reveal that the highly dispersed CuO species is the key oxidative component in the catalyst. SEM and TEM results show that VOx is beneficial to enhance the dispersion of CuO in the catalyst. The adsorbed oxygen content of CuO@TiO2 catalyst is increased by VOx-modification, as indicated by EPR result. An appropriate amount of adsorbed oxygen in the catalyst can improve the oxidation activity of the catalyst and assure high selectivity of N2. Finally, through the in-situ DRIFTs the reaction intermediate NHx is captured, and a reliable SCO reaction pathway of TEA is proposed. This study provides a solution for the disposal of tertiary amines from NVOCs.