Synthesis and characterization of a series of mesoporous nanocrystalline lanthanides phosphate

Abstract

A series of lanthanide (LA) phosphate were prepared by using N-(2-hydroxyethyl) ethylenediane-N,N′,N′-triacetic acid (H3hedtra) as a chelating agent. The obtained samples were characterized by using X-ray diffraction (XRD), nitrogen adsorption-desorption isotherm, thermal analysis (TG-DTA), transmission electron microscope (TEM) and TPD-ammonia desorption. The results showed that samples prepared through chelating agent route possessed smaller particle size which led to higher specific surface area with increased acidic sites compared with the reference samples prepared free of H3hedtra. It was also found that the acidic strength increased gradually from the light lanthanide phosphate to heavy lanthanide phosphate. Besides, pore size of the samples could be controlled by altering the mole ratio of the lanthanide(LA): H3hedtra. Pore size distribution of the samples became narrower through synthesis in the presence of H3hedtra. The precursor sol complex was investigated by FTIR and XRD and mesopore formation mechanism had been discussed.