Tungsten oxide by non-hydrolytic sol–gel: effect of molecular precursor on morphology, phase and photocatalytic performance

Abstract

A practical gram-scale synthesis of high surface area blue tungsten oxide via a non-hydrolytic sol–gel method is reported. The use of diisopropyl ether in 1,2-dichloroethane at 180 °C transforms W(VI) and W(IV) chloride precursors into WO_x materials of cube or rod-like morphology respectively. These oxides are characterised by a range of methods including TEM, N₂ adsorption–desorption, XRD, XAS, EPR, UV-Vis DRS, elemental analysis and conductivity measurements. Treatment of WO_x under N₂ causes a decrease in surface area and increase in electrical conductivity. Prepared materials are investigated as catalysts for oxygen evolution by photocatalytic water splitting.