we have prepared SZ by impregnation of ZrOCl2·8H2O as precursors over cordierite. The resulting samples were dried at 105 °C and then calcined in air (SZ at 500 °C) for 3 h to obtain the corresponding active oxides. However, under the experimental conditions (hydrothermal experiments T=170-210 C, t=30-180 min, P