Lanthanum-based coordination polymers microplates using a “green ligand” EDTA with tailorable morphology and fluorescent property

Abstract

In this work, lanthanum (La)-based coordination polymers (CPs) microplates were fabricated in a simple bottom-up way by hydrothermal reaction of La³⁺ and a “green ligand” EDTA (ethylenediamine-N,N,N′,N′-tetraacetate). Under similar conditions, cerium (Ce)–EDTA CPs microplates could also be fabricated, which had the same crystalline phase and similar chemical composition to the La–EDTA CPs. The formation mechanism of the La–EDTA CPs was investigated and proved to follow the Ostwald ripening process. Moreover, its morphology could be tuned facilely by varying the quantity of EDTA and the total concentrations of reactants, and several kinds of micro/nanostructures were produced such as nanoparticle clusters, nanofibers, large or uniform microplates. Furthermore, the as-prepared La–EDTA CPs exhibited green light emission property after doping with Tb³⁺, and La₂O₃ nanorods as well as CeO₂ microplates were also prepared by calcination of their corresponding CPs precursors.