Microwave-Assisted Synthesis of Mixed Metal-Oxide Nanoparticles

Abstract

Nanoparticles of mixed metal oxides, ZrO 2 , ZrTiO 4 , and ZrV 2 O 7 were prepared by microwave-assisted citrate sol-gel and solution combustion method. The prepared nanoparticles were characterized for their structural details using XRD and TEM techniques. The broadening of Raman bands is ascribed to local compositional fluctuations or local positional disordering produced due to random distribution of Zr 4+ and Ti 4+ between equivalent sites. The XPS spectra confirm the incorporation of Ti in ZrO 2 and suggest Zr as well as Ti in +4 oxidation state. Gelation and fast combustion seem to be the reason for smaller particle sizes. ZrV 2 O 7 nanocrystalline material was synthesized by microwave- assisted solution combustion method. Low angle powder XRD measurements confirm the mesoporous nature of the prepared material. The effect of calcination temperature on the phase transformation of the materials has been investigated. Among tetragonal, monoclinic, and cubic phases, the monoclinic phase is predominant at higher calcinations temperature. The XPS confirms the incorporation of V 2 O 5 in ZrO 2 and suggests that Zr and V are in the same oxidation state (+4). The average particle sizes for ZrO 2 , ZrTiO 4 , and ZrV 2 O 7 were found to be in the ranges of 5–10 nm, 2–5 nm, and 10–50 nm, respectively.