Investigating the role of microwave thermal and non-thermal effects on WO3-graphene oxide composite synthesis

Abstract

The effects of microwave-assisted synthesis on the morphology and crystalline structure of WO₃-graphene oxide (GO) composites have been investigated. Using two different microwave reactors, evidence supports that thermal and non-thermal effects significantly influence the properties of the synthesized materials. The findings reveal that the microwave cavity geometry affects how the microwaves are “delivered” to the reactional cavity as a function of time; it also orientates the growth process of the WO₃ particles. Consequently, the crystalline structure and morphology are affected. As a result, the WO₃-GO composites produced using a CEM reactor exhibit a rounded shape and hexagonal phase of WO₃, besides enhanced reduction of GO. Whereas the composites made using an Anton-Paar reactor are composed of sheets and flowers of WO₃ with hexagonal, triclinic and/or WO₃ hydrate structures and cause a lower reduction on the GO.