CrOx Anchored on the Black-TiO2 Surface via Organic Carboxylic Acid Ligand and Its Catalysis in Oxidation of NO

CrOx/black-TiO2 catalysts were prepared by ligand-assisted (citric acid, oxalic acid and ethylenediaminetetraacetic acid) impregnation method. These catalysts were characterized in detail by means of X-ray diffraction, Raman, BET, X-ray photoelectron spectroscopy, H-2 and O-2(NO) temperature programmed reduction or desorption and in-suit DFTIR spectra. The results indicated that ligands assistance was beneficial for CrOx interacted with oxygen vacancies and O-Ti-O structures. Among all the catalysts, CrOx/black-TiO2/CA (modified by citric acid) revealed excellent catalytic activity and stability for NO oxidation in the temperature range of 200-450 degrees C. The characterization results exhibited that the interaction existed between CrOx and oxygen vacancies resulting in more Cr6+. Moreover, the strong interaction between CrOx and O-Ti-O was attributed to the modification of carboxylic acid, which increased the content of Cr3+ and chemical adsorption oxygen. High content of chemical adsorption oxygen promoted the adsorption ability of O-2, and Cr6+ enhanced the adsorption capacity of NO. Hence, chemical adsorption oxygen and Cr6+ synergistically promoted the NO oxidation. [GRAPHICS] .

Automated summary

Ligand-assisted impregnation method was used to prepare CrOx/black-TiO2 catalysts, which showed enhanced interaction between CrOx and oxygen vacancies/O-Ti-O structures. Modification by citric acid increased the content of Cr3+ and chemical adsorption oxygen, promoting the adsorption ability of O-2 and enhancing the adsorption capacity of NO, synergistically promoting NO oxidation.