通过氢还原热处理提升TiO_(2)薄膜的抗菌性能

Antibacterial Properties of TiO2 Film Improved by Hydrogen Reduction Heat Treatment

提升在可见光区间的抗菌效率一直是二氧化钛(TiO_(2))抗菌性能研究的重要方向.采用脉冲激光沉积(PLD)制备TiO_(2)薄膜,并通过氢还原热处理的方法提升TiO_(2)表面的氧空位浓度从而增强其抗菌性能.结果发现,在以单晶氧化钇稳定的氧化锆(YSZ)为衬底时,生长的TiO_(2)薄膜为高度择优取向的锐钛矿相.生长温度越高,锐钛矿相的XRD衍射峰越强,薄膜越致密.将在600℃下生长的350 nm厚的TiO_(2)薄膜进行抗菌性能测试,发现其抗菌率约为86%.对样品进一步在4%H2氛围下进行还原处理,发现其抗菌率提升到约为97%.通过XPS、UV-Visible和PL测试,发现TiO2经过还原热处理后在其表面形成更多的氧空位,在TiO_(2)带隙中形成氧空位缺陷能级,导致在可见光区域吸光性能增强,使其具有更高的抗菌性能.通过氢还原过程调控材料的缺陷组成,并研究TiO_(2)薄膜的光催化抗菌性能及抗菌机理.这种简易的调控TiO_(2)光吸收的方法可为规模生长提供技术可行性.

Titanium dioxide(TiO_(2))has good photocatalytic activity and can degrade environmental pollutants by oxidation.It has been used in photocatalysis,on antibacterial,antifouling and self-cleaning surfaces,and ultraviolet(UV)detectors.However,it predominantly absorbs UV light and has low absorption of visible light.Improving antibacterial efficiency in the visible light region has consistently been a key research direction for TiO_(2)antibacterial properties.Currently,to improve TiO_(2)photocatalytic efficiency under visible light,multiple schemes have been proposed,such as metal or non-metal doping,and laser surface or vacuum heat treatment.These methods introduce point defects in the TiO_(2)lattice,and narrow the band gap by changing the semiconductor energy band and introducing impurities or defect energy levels in the band gap,thus enhancing visible light absorption.To better understand the TiO_(2)antibacterial mechanism,it is necessary to accurately control its morphology,composition,and crystal structure.Thin film materials adequately meet these requirements.Recently,pulsed laser deposition(PLD)has become a widely adopted film deposition technology owing to its simple system setup,wide range of deposition conditions,material selection and ability to prepare high-quality repeatable films.In this study,TiO_(2)thin films are prepared using PLD,and the oxygen vacancy concentration on the TiO_(2)surface is increased by hydrogen reduction heat treatment to enhance its antibacterial properties.Results demonstrate that the TiO_(2)films grown on a single crystal yttria stabilized zirconia(YSZ)substrate are the highly preferred anatase phase,and the higher the growth temperature,the stronger the X-ray diffraction(XRD)peak of the anatase phase and the denser the film.The antibacterial properties of 350 nm thick TiO2 film grown at 600℃were measured and it was identified that the antibacterial rate is approximately 86%.The sample was further reduced in a 4%H2 atmosphere,and it was confirmed that the antibacterial rate increased to approximately 97%.Test results demonstrate that through X-ray photoelectron spectroscopy(XPS),a UV-visible spectrophotometer(UV-visible)and a laser Raman spectrometer(PL),additional oxygen vacancies formed on the TiO_(2)surface after reduction heat treatment,and oxygen vacancy defect energy levels formed in the TiO2 band gap.This resulted in enhanced light absorption in the visible region and higher antibacterial performance.The material defect is controlled by the hydrogen reduction process,and the TiO_(2)thin film photocatalytic antibacterial property and antibacterial mechanism were studied.This straightforward method for regulating TiO_(2)light absorption provides technical feasibility for scale growth.