Photocatalytic performance of few-layer Graphene/WO3 thin films prepared by a nano-particle deposition system

Abstract

The nano-particle deposition system (NPDS) is an environmentally friendly, room temperature, dry particle deposition technique to impart thin films of metal or ceramic particles onto different substrates without any additional chemicals. In this work, graphite and WO3 powders with different graphite contents (0-30 wt%) were successfully deposited on a polypropylene substrate by an NPDS without generating any thermal damage of the substrate. The graphite particles can easily be fragmented into small few-layer graphene nano-flakes along with WO3 utilizing the high kinetic energy during NPDS. With field emission scanning electron microscopy, fragmentation of particles due to the high impact velocity of the powders during deposition was observed. X-ray diffraction showed the absence of any graphite peak in the composite thin film. Finally, the existence of few-layer graphene in the fabricated thin film was confirmed by Raman spectroscopy. To evaluate the photocatalytic activity of the fabricated thin films, degradation of methylene blue dye under illumination of light for 2 h was observed. Degradation of the dye was evaluated using absorbance values measured by UV/Vis spectroscopy before and after the test. The results showed that the photocatalytic performance was significantly enhanced when the WO3 contained added graphite and suggested that 15 wt% of graphite was the optimal level in the composite thin film. The photocatalytic reaction followed pseudo-first-order kinetics. Repeatability determines the feasibility of thin films in using real applications. Here, all the thin films showed good stability up to five cycles. The few-layer graphene/WO3 composite thin films were easily prepared for the photocatalytic applicadon using NPDS.