Structure and composition study of carbon-doped titanium oxide film combined with first principles

Carbon-doped titanium oxide(C/Ti-O)films were prepared on Si(100)wafer,stainless steel(type 304)and glass by reactive magnetron sputtering(RMS)using CO2 gas as carbon and oxygen source under room temperature(RT).X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)were used to analyze structure and composition of the as-prepared C/Ti-O film.It could be observed from XRD that the as-prepared C/Ti-O film contained TiO crystal phase structure.Ti2p XPS spectrum of the as-prepared C/Ti-O film showed that the valences of titanium were made up of Ti^(2+),Ti^(3+)and Ti^(4+).C1s XPS spectrum revealed that carbon was doped into titanium oxide based on the existence of the typical Ti-C bond.The optical absorption curve by ultraviolet-visible(UV-Vis)spectrophotometer showed that the C/Ti-O film appeared the remarkable red shift of absorption edge,which contributed to C substitution in O sites in amorphous TiO_(2).Photocatalysis test using methyl orange(MO)as indicator confirmed that the as-prepared C/Ti-O film had photocatalytic activity.Combined with the results of the tests and first-principles calculations,a potential photocatalysis mechanism was proposed.