The surface and catalytic properties of titania-supported mixed PMoV heteropoly compounds for total oxidation of chlorobenzene

Heteropoly catalysts based on the mixed PMoV heteropoly compounds (HPC) with Keggin structure were prepared. The behaviors of the samples (in bulk and in titania-supported form) as a function of temperature treatment in the range of 343-923 K and the number of introduced V atoms into the heteropoly anions were studied. The catalytic activity of titania-supported catalysts was evaluated in the reaction of total oxidation of Cl-benzene at 473 K. The samples were characterized by S-BET method, thermogravimetric analysis (TGA), Fourier transform infrared,spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The XRD, IR and Raman results provided clear evidence that V indeed is incorporated into the Keggin unit. Introduction of one V atom into heteropolyanion leads to a significant increase of its thermal stability. On the other hand, the presence of the vanadium centers appears to be responsible for the increased activity of the titania-supported samples in the reaction of total oxidation of chlorobenzene. (c) 2006 Elsevier B.V. All rights reserved