The Research Of Black TiO_2-x Material With Adjustable Bandgap For Photoelectrochemical Antibacterial Performance

Infectious diseases caused by bacteria have become one of the major factors threatening human survival.Antibiotics are widely used to treat microorganism infections.But the excessive use of antibiotics will result in resistant bacteria/viruses,thus further threatening public health.A face mask is an effective defensive tool to greatly reduce exposure to bacteria/viruses in the air.However,it increases the risk of secondary infection due to the lack of self-cleaning ability.And the short service life is not conducive to environmental protection.Therefore,the exploration of an effective sterilization strategy with long service life for face masks is still a great challenge.Photocatalysis with the characteristic of being efficient,green and stable is expected to replace antibiotics in treating bacterial infectious diseases.However,TiO₂as the classic semiconductor still suffers severe inefficiency due to the wide bandgap,narrow optical response regions and fast charge recombination.In this paper,black TiO_2-xwith excellent optical properties and electronic structure was prepared as a novel photoactive material using oxygen vacancy engineering.The photoelectric synergistic sterilization platform（PEC）which combined electrochemistry and photocatalysis was an innovative way to improve photocatalytic performance and inhibit the efficient and rapid inactivation of E.coli.In addition,B-TiO_2-xNWs grown on flexible carbon cloth（CC）could be formed as a portable self-cleaning face mask.After combining with the ionic liquid[BMIM][Cl]coating,the stability and reusability would be greatly enhanced.The novel and effective strategy showed great potential application in treating bacterial infections treatment and personal protection in epidemic conditions.The research of this paper mainly was consisted of the following three parts:Chapter 1:IntroductionThis chapter introduced the background and new therapeutic methods of bacterial infections,briefly described the principles and applications of photoelectrochemistry,and clarified the current development and the research progress of black titanium dioxide.Chapter 2:The photoelectric synergistic platform for efficient inactivation based on rationally designed black TiO_2-xNanowires.Photocatalytic therapy has the characteristics of high efficiency,stability and green,which is expected to replace antibiotics in treating drug-resistant bacterial infectious diseases.However,the rapid recombination of photogenerated carriers in the photocatalyst severely limits the therapeutic effect.Therefore,the black TiO_2-xNanowires(B-TiO_2-xNWs)was rationally designed as the photoactive material in photoelectrochemical（PEC）therapy platform.The black TiO_2-xnanowires with the high concentration of oxygen defects had the characteristics of narrow bandgap,wide photo-response range and high carrier mobility rate,which greatly produced active oxygen species（ROS）.The PEC bactericidal method inactivated more than 90%of bacteria within 20 minutes,which was 10 times more antibacterial than traditional photocatalytic therapy.In addition,B-TiO_2–xNWs with broad-spectrum antibacterial properties and stability would be used to prepare self-cleaning photoelectric sterilization masks,which provided important protection for the human body during the airborne transmission of bacterial pathogens.Chapter 3:PEC sterilization performance of[BMIM][Cl]/black TiO_2-xNWs with high photoelectric activity and stability.Black TiO_2-xshowed excellent photoelectric sterilization performance.However,applying the high electrode voltage could reduce the concentration of oxygen vacancies and destroys the internal electronic structure in the photoelectrode.In this chapter,we proposed the preparation of high photoelectric activity and stability[BMIM][Cl]/black TiO_2-xNWs composites by the coordination of ionic liquid[BMIM][Cl]coating with B-TiO_2-x.The ionic liquid coating could improve the charge transfer rate at the interface of semiconductor and promote the rapid separation of photogenerated electron-hole pairs.The composite materials achieved 99%inactivation of E.coli within 10 s,showing ultra-efficient and rapid PEC bacteriostatic performance.In addition,[BMIM][Cl]provided the protective layer with the wide electrochemical window and high stability for B-TiO_2-x,which enabled B-TiO_2-xNWs to maintain excellent optical properties and electronic structure,and have a longer useful life in application.