Synthesis and Characterization of New Iron and Zinc Phosphate Materials with Open Framework

ABSTRACTOpen framework materials are of great interest due to the applications in the fields of adsorption, ion exchange, molecular sieving and catalysis. Metal phosphates are very important open framework materials due to the rich crystallography. Several new iron phosphate materials have been synthesized and characterized in our lab. Two new iron (III) phosphates, FePO4, have been synthesized from careful dehydration of hydrothermally prepared monoclinic and orthorhombic hydrated phosphates FePO4·2H2O. Reversible insertion and extraction of lithium into new iron phosphate hydroxide materials with 3-d rod-packing framework shows it to be an excellent intercalation material. Several other transition metals are also incorporated successfully into these compounds without changing the structure. With ethylenediamine as template, 1-D chain, 2-D layered and 3-D network iron phosphate materials were synthesized. The structure, electrochemical and magnetic properties of these compounds were studied. Meanwhile, two new zinc phosphates with methylammonium templates were also synthesized. There are infinite Zn-O-Zn chains in one of the compounds, while closed 4-member circuits made up from Zn-O-Zn linkage present in the other.