Influence of synthesis parameters on physicochemical properties of CuO/ZrO2 catalysts

CuO/ZrO2 (Cu/Zr) catalysts were synthesized via the co-precipitation method using Na2CO3 as the precipitating agent. The influence of CuO/ZrO2 ratio, aging time and calcination temperature of catalyst precursors on the physicochemical properties of Cu/Zr catalysts was studied. The catalysts were characterized by means of N-2 adsorption, temperature-programmed reduction, N2O dissociative chemisorption, X-ray diffraction, inductively coupled plasma optical emission spectrometer and CO2 temperature-programmed desorption. It was found that only for samples calcined at 550 degrees C the ZrO2 was present as the tetragonal phase (t-ZrO2). In the case for samples which were aged for 1 h, metallic copper dispersion (D-Cu) does not depend on calcination. On the other hand, for non-aged catalysts a decrease in D-Cu is observed with higher temperature of calcination. The temperature corresponding to maximum reduction rate (T-max) decreases for samples with higher D-Cu. The contribution of weak basic site is the highest for catalysts which were aged, whereas for non-aged catalysts mainly medium basic sites dominate on the surface.