Exploring the role of fuel on the microstructure of VOx/MgO powders prepared using solution combustion synthesis

We report findings of a structural characterization of VOx/MgO powders prepared by a stoichiometric solution combustion synthesis using five different fuels. Characterization of the synthesized powders was done using X-ray diffraction, Raman spectroscopy, Inductively Coupled Plasma Emission Spectroscopy, Scanning Electron Microscopy and Aberration Corrected Transmission Electron Microscopy. It was found that the microstructure and extent of vanadate phase formation and dispersion, for each powder, were influenced by the selection of fuel used. By correlating experimentally extracted microstructural parameters to calculated thermodynamic parameters we demonstrate the important role of the fuel in controlling the reaction kinetics. Specifically, we highlight the role of a fuel's reducing valency in regulating the maximum temperature and heating rate of a reaction. Based on the findings we propose a model of formation for the material system, demonstrating the potential of this novel one-step method for the controlled synthesis of VOx/MgO powders for catalytic applications.