xrd and tpr studies of cu-al hydrotalcite derived highly dispersed mixed metal oxides

摘要

A series of Cu/Al catalysts,containing different proportions of copper and aluminium,have been prepared by coprecipitation using metal nitrate precursors and Na_2CO_3.The dried precipitate catalyst precursors were characterized by X-ray diffraction (XRD) to show the presence of Cu-Al binary hydrotalcite-like phase.The dried precipitates were calcined at 873 K for 3h.The calcined catalysts were characterized by XRD and temperature-programmed reduction (TPR) methods to show the presence of unidentified mixed oxides.The results showed that the extent of metal-support interaction increased with copper loading due to the mixed oxides formed from the hydrotalcite-type phase during calcination.High dispersion of the mixed metal oxides was indicated by comparison with similar studies on Cu-Al catalysts,prepared by similar methods,whose precursors showed no hydrotalcite formation.