In view of their scientific and technological applications, optimization of the preparation conditions to produce phase pure samples with controlled structure, morphology, optical and electronic properties is very important. A wide range of synthesis techniques are reported for the preparation of MoO3 and WO3 such as thermal evaporation [16], sputtering [17], chemical vapor deposition [18], spray pyrolysis [19], hydrothermal process [20], sol–gel method [21] etc. The composites of MoO3–WO3 are receiving In view of their scientific and technological applications,optimization of the preparation conditions to produce phase pure samples with controlled structure, morphology, optical and electronic properties is very important. A wide range of synthesis techniques are reported for the preparation of MoO3 and WO3 such as thermal evaporation [16], sputtering [17], chemical vapor deposition [18], spray pyrolysis [19], hydrothermal process [20], sol–gel method [21] etc. The composites of MoO3–WO3 are receiving.