Insight Into the CuOx Interacts with Oxygen Vacancies on the Surface of Black-TiO2 for NO Oxidation

Designing non-precious catalysts to synergistically expose high active sites and exhibit optimized NO oxidation activity still remains a big challenge. Herein, a low-cost and high-active CuOx/black-TiO2 catalyst was prepared by impregnation method for NO oxidation. The CuOx/black-TiO2 (molar ratio of Cu/Ti is 0.05) exhibited the highest NO oxidation efficiency (53.43%) at 350 °C, which was higher than that of corresponding CuOx/TiO2 (38.86%) catalyst. Moreover, the kinetics of NO conversion over CuOx/black-TiO2 and CuOx/TiO2 catalysts were also studied. Raman spectra results indicated that CuOx interacted strongly with oxygen vacancies on the surface of black-TiO2. XPS further proved that electrons transferred from black-TiO2 to CuOx, leading to a higher proportion of Cu+ on CuOx/black-TiO2 than that of CuOx/TiO2. In addition, CuOx/black-TiO2 exhibited better reduction property and bigger adsorption capacity of NO and O2 than those of CuO/TiO2, confirming by H2-TPR and NO (O2)-TPD, respectively. Finally, the possible mechanism of CuOx/black-TiO2 for NO oxidation was proposed.