Study On The Composition,Structure And Photocatalytic Properties Of Carbon Doped Ti-O Films Prepared By RF Sputtering Under CO₂ Reactive Atmosphere

With the rapid development of modern society,the loss and influence of environmental pollution and corrosion on social economy and industrial production are becoming more and more serious.The development of clean and renewable energy,environmental pollution control and corrosion protection technology has become an urgent need for the sustainable development of human society.Titanium dioxide?TiO₂?has been widely used in many fields,such as solar cells,surface antibacterial,wastewater treatment and organic dye degradation,due to its good chemical stability,non-toxic and pollution-free,and excellent photocatalytic activity.However,due to the wide band gap of TiO₂ and the high photoelectron-hole recombination rate,the photocatalytic activity of TiO₂ is not high.The modification of TiO₂ to narrow the band gap width of TiO₂ or reduce the photoelectron-hole recombination rate so as to improve the photocatalysis of TiO₂ has become a hot topic in current studies.Nonmetallic element doping is one of the modification methods.By RF magnetron sputtering method in this paper,with the CO₂ and O₂ as the reaction gas,in Si and the carbon steel surface preparation C doped Ti-O?C:Ti-O?thin films,the change of rf power supply power and substrate negative bias,research the two kinds of process parameters on the film composition,structure,mechanical property,surface morphology,band gap width,the influence law of surface energy,and evaluate the photocatalytic performance of the film.AFM characterization of C:Ti-O film showed that the surface morphology of the film was not significantly different,both were of sharp columnar structure,and the surface of the sample was relatively flat.XRD and Raman spectroscopy were used to analyze the structure of the film.The results showed that C:Ti-O film was mainly rutile phase with a certain amount of amorphous TiO₂.XPS analysis confirmed the existence of Ti-C bond in the film of C:Ti-O,indicating that C atom replaced part of O atom,and C element successfully doped.The transmission spectrum measured by UV-vis spectrophotometer is used to calculate the band gap width of thin film by Tauc drawing method.The results show that doping C element can effectively reduce the band gap width of'thin film.The contact Angle between the film surface and water and diiodomethane was measured and the surface energy was calculated.The results show that the polar component of surface energy increases with the doping of carbon in Ti-O films.C:Ti-O film has an enhanced ability to accept electrons on the surface of the film after ultraviolet irradiation.The surface energy is generally increased by ultraviolet light.The hardness,young's modulus and membrane adhesion of C:Ti-O thin film were tested in the nanomechanical system.The results showed that the hardness and young's modulus of C:Ti-O thin film hardly changed with the increase of power,and the membrane adhesion first increased and then decreased.However,when oxygen was involved in the reaction,the hardness increased significantly,the brittle tendency of the film increased,and the membrane base binding force becomes worse.However,with the increase of negative bias of the substrate,the hardness generally shows an upward trend,but the modulus does not change regularly.The membrane base binding force shows a continuous increasing trend within a certain range of negative bias of the substrate,but begins to decrease at-200V.The results of methyl orange degradation experiment showed that the synthesized Ti-O and C:Ti-O films showed certain photocatalytic activity,and carbon doping could improve the photocatalytic performance of Ti-O films to some extent.With the increase of RF power,the photocatalytic activity decreased,indicating that the band gap narrowing did not improve the photocatalytic activity.With the increase of negative bias,the photocatalytic performance first increases and then decreases.Excessive negative bias of the substrate will lead to bond fracture on the surface of the thin film,which will affect C doping,resulting in a decline in photocatalytic effect.