Novel microwave initiated solid-state metathesis synthesis and characterization of lanthanide phosphates and vanadates, LMO 4 (L = Y, La and M = V, P)

Abstract

A novel solid-state metathesis (SSM) approach represented by the reaction (LCl 3 + Na 3VO 4 → LVO 4 + NaCl) (L = Y, La) is proposed to synthesize technologically important rare-earth phosphates and vanadates. The SSM reaction, driven in the forward direction is facilitated by the formation of high lattice energy by-product like NaCl. The structural, thermal, optical, and chemical properties of synthesized powders are determined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and diffused reflectance (DR) spectra in the UV–vis range. The direct band gap of the synthesized materials was found out to be ∼3.5 eV for LaVO 4, YVO 4, YPO 4 and ∼2.6 eV for LaPO 4.