Cu-ZnO-Al2O3 catalysts for OSRM process: the influence of different synthesis conditions of the LDH precursors

Cu-ZnO-Al2O3 catalysts for methanol oxidative steam reforming were prepared from mixed Cu/Zn/Al hydroxycarbonates obtained from metal nitrates or chlorides by the method of homogeneous precipitation. The samples were characterized by XRPD, TG/DTA, N2 adsorption, FTIR, TPR, NH3-TPD. The Cu dispersion was measured by reaction with N2O. Less reducible Cu species and higher concentration of acid sites were found in the catalysts derived from metal chlorides. The Cu dispersion did not depend on the nature of the precursor salts. All catalysts appeared very active, giving almost complete CH3OH conversion at 300-350°C and H2 yield up to the maximum allowed by the feeding composition. The hydrogen production rate increased with Cu content and was higher for catalysts derived from nitrates. The activation energy of the reaction was correlated with surface acidity, suggesting that the oxide matrix was involved in methanol adsorption and dissociation