Simultaneous incorporation of palladium and zirconium ions in Mg-Al layered double hydroxides by co-precipitation

摘要

Simultaneous incorporation of palladium and zirconium ions in Mg-Al layered double hydroxides (LDHs) was attempted by co-precipitation. Mixed oxides were obtained by calcination at 500 ℃. XRD patterns of as-synthesized samples showed the formation of well-crystallized LDHs at lower Zr contents. The CC>3~ content of the solids has been determined to have information on the possible incorporation of Zr~4+ into the bru-cite layer of the hydrotalcites. The values obtained showed that Zr~4+ can incorporate into brucite sheets at Zr content lower than 10 mol%. SEM and TEM images indicated that the resulted LDHs with lower Zr content exhibited plate-like structure. Thermal calcination at 500 "C results in the formation of mixed oxides containing MgO, PdO, ZrC>2 crystallites and a solid solution formed by some of the Zr~(4+) cations dissolving along with Al~(3+) to MgO lattice.