Photocatalytic Oxidation of NO over Composites of Titanium Dioxide and Zeolite ZSM-5

Catalysts

Roger Gläser¹  Wolf-Dietrich Einicke¹  Akram Tawari¹ 

[1] Institute of Chemical Technology, Universität Leipzig, Linnéstraβe 3, 04103 Leipzig, Germany;

关键词: TiO2;    PCO;    photocatalytic activity;    NOx;    XRD;    SEM;    preparation techniques;   

DOI  :  10.3390/catal6020031

来源: DOAJ

【 摘 要 】

Composites of TiO2 (Hombikat, P25, sol-gel synthesis) and zeolite ZSM-5 (nSi/nAl = 55) with mass fractions from 25/75 to 75/25 were prepared by mechanical mixing, solid-state dispersion and sol-gel synthesis. Characterization of the composites by X-ray diffraction (XRD), N2-sorption, scanning electron microscopy (SEM), and UV-Vis spectroscopy show that mechanical mixing and solid-state dispersion lead to comparable textural properties of the composites. A homogeneous distribution and intimate contact of small TiO2 particles on the crystal surface of zeolite ZSM-5 were achieved by sol-gel synthesis. The composites were studied in the photocatalytic oxidation (PCO) of NO in a flatbed reactor under continuous flow according to ISO 22197-1. The highest NO conversion of 41% at an NO2 selectivity as low as 19% stable for 24 h on-stream was reached over the TiO2/ZSM-5 composite from sol-gel synthesis with equal amounts of the two components after calcination at 523 K. The higher activity and stability for complete NO oxidation than for pure TiO2 from sol-gel synthesis, Hombikat, or P25 is attributed to the adsorptive properties of the zeolite ZSM-5 in the composite catalyst. Increasing the calcination temperature up to 823 K leads to larger TiO2 particles and a lower photocatalytic activity.

【 授权许可】

Unknown