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Nanoparticles of mixed metal oxides, ZrO2, ZrTiO4, and ZrV2O7 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 Zr4+ and Ti4+between equivalent sites. The XPS spectra confirm the incorporation of Ti in ZrO2 and suggest Zr as well as Ti in +4 oxidation state. Gelation and fast combustion seem to be the reason for smaller particle sizes. ZrV2O7 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 V2O5 in ZrO2 and suggests that Zr and V are in the same oxidation state (+4). The average particle sizes for ZrO2, ZrTiO4, and ZrV2O7 were found to be in the ranges of 5–10 nm, 2–5 nm, and 10–50 nm, respectively.

A new type of mesoporous nanocrystalline vanadium incorporated zirconia material is synthesized by solution combustion method. The material is characterized by X-ray diffractometer (XRD), Brunanuer, Emmett and Teller (BET) surface area, Raman spectroscopy, and transmission electron microscopy (TEM) techniques. The XRD studies revealed the material to be a mixture of ZrO 2 and ZrV 2 O 7 . The effect of calcination temperature on the phase transformation of the materials has been investigated by XRD measurements. The material has been used as catalyst for oxidative dehydrogenation (ODH) of ethylbenzene (EB) using air as oxidant for the first time. A DFT modeling of the transition state of the reaction suggests the formation of a hydroxyl species over the catalyst surface which is believed to have been formed due to abstraction of a hydrogen atom from ethyl benzene. The presence of hydroxyl species on the catalyst surface has also been identified by FTIR record of the catalyst after treating it with ethyl benzene at 200 C. A tentative mechanism for the reaction is proposed.

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