Ionothermal synthesis of Ce/Nd-containing UiO-7 molecular sieve in eutectic mixture

Abstract

Ce/Nd-containing UiO-7 molecular sieves were ionothermally synthesized in imidazole–tetramethylammonium chloride eutectic mixture. The reaction conditions were systematically investigated. It is concluded that the crystallinity of products changes with Ce(Nd)/Al ratios and crystallization temperature. The morphologies and properties of Me-UiO-7 (Me = Ce, Nd) were characterized through X-ray powder diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectroscopy (UV-Vis), Brunauer–Emmett–Teller (BET) and thermogravimetric analysis (TG). The results indicate that hetero atom Ce and Nd occupy the sites of Al in crystal lattice of molecular sieves by isomorphous replacement and partially entered the framework of UiO-7 molecular sieve. The morphology of Ce-UiO-7 is rectangular columnar with smooth surface, and the morphology of Nd-UiO-7 leaf-like with rough surface. The thermal stability of Ce-UiO-7 and Nd-UiO-7 are both superior to UiO-7. The BET surface areas of Ce-UiO-7 and Nd-UiO-7 are also larger than that of UiO-7.