화학공학소재연구정보센터
Applied Catalysis B: Environmental, Vol.158, 258-268, 2014
Focus on the modified CexZr1-xO2 with the rigid benzene-muti-carboxylate ligands and its catalysis in oxidation of NO
A modified Cr/CexZr1-xO2 with the rigid benzene-muti-carboxylate ligands are prepared and studied on the oxidation of NO. These catalysts were investigated in detail by means of X-ray diffraction (XRD), High resolution transmission electron microscope (HR-TEM), Brunauer-Emmett-Teller (BET) surface area analysis, Ultra violet-visible diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), NO(O-2) Temperature-programmed desorption (NO(O-2)-TPD) and in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The results demonstrated that the catalysts prepared with cinnamic acid as precipitant showed a higher surface area, a lower band gap and a stronger ability to adsorb reactant gas. Otherwise, the ligands such as terephthalic acid and trimesic acid were unfavorable for the synthesis of CexZr1-xO2 due to the long distance between the carboxyl groups. Furthermore, the pi-pi conjugated effect of the cinnamic acid balanced the charge in the precursor of the catalysts prepared with cinnamic acid, thus leading to their band gaps lower than that of other catalysts after calcinations. The catalytic performance over the catalysts prepared with cinnamic acid exhibited the highest NO conversion, and the preparation with one-pot method was simpler. Moreover, the catalyst prepared with one-pot method showed well ability to resist the poison effect of H2O and SO2, which was due to the large surface area. Finally, while combined the XPS analysis, in-situ DRIFTS demonstrated that the adsorbed NO interacted with the adsorbed O-2 to generate NO2, and the adsorption and activation O-2 was the key factor. (C) 2014 Elsevier B.V. All rights reserved.