Study Of Copper Oxide Photocatalytic Films Deposition By Magnetron Sputtering Method

The treatment of pollutants in water is a problem that needs to be solved urgently.Semiconductor photocatalysis technology is an important way to decompose or mineralize organic pollutants in water.It has the advantages of low cost,sustainability,and no secondary pollution.Among the discovered photocatalysts,Cu2O has a direct band gap of 1.9-2.2 eV,and is a P-type semiconductor that can absorb and utilize visible light.In the future,it is an ideal photocatalytic material that responds to visible light.In this paper,a medium-frequency pulsed magnetron sputtering method is used to prepare a copper oxide film on a medical glass slide.The factors influencing the stability of copper oxide were studied,and the better photocatalytic activity of copper oxide was obtained.In this paper,the effects of the two sputtering parameters,oxygen flow rate and deposition time,are investigated in depth.X-ray diffractometer?XRD?,atomic force microscope?AFM?,field emission scanning electron microscope?FE-SEM?,X-ray photoelectron spectroscopy?XPS?and ultraviolet-visible absorption spectrum?UV-Vis?were used to characterize the structure,morphology and absorbance of the prepared film.Using visible light lamps as irradiation source and methyl orange as the simulated pollutant,the photocatalytic decolorization tests were performed for the copper oxide films and the influence of sputtering parameters was evaluated.The results show that uniform and smooth thin films can be prepared by the intermediate frequency pulsed magnetron sputtering method and the films absorb visible light with wavelength shorter than 541 nm.With the increase of the oxygen flow rate,a film made of Cu and Cu₂O phase mixed into a single phase Cu₂O,continue to increase the flow of oxygen into the mixed phase of the film of Cu₂O and Cu₄O₃.To prepare films with good photocatalytic activity,oxygen flow rate and deposition time are the key process parameter.Based on the experimental data of oxygen flow rate and deposition time,When the oxygen flow rate was 6sccm and the deposition time is 15 min,the prepared film showed the best photocatalytic activity.The 24 W fluorescent lamp is irradiated for 4 hours.The methyl orange solution was degraded by 55.6%.With oxygen flow rate,the change trend of the film's band gap is consistent with the film's stability in the dark.By the way,the films with the oxygen flow rate of 6 sccm-6.5 sccm show highest stability and purest Cu₂O.Changing the deposition time does not affect this result.It shows that the crystal structure of the film has a great influence on the stability of the copper oxide film.The Mulliken electronegativity theory can explain the photocatalytic mechanism of Cu₂O.