Construction Of NIR Ⅰ-Ⅱresponse ZrO_2-x-B By Double Doping Strategy And Its Application In Photocatalysis And Cancer Phototherapy

The development of semiconductor nanomaterials with high-efficiency near-infrared I-Ⅱ（NIR I-Ⅱ,750-1350 nm）response has become one of the research hotspots in the fields of photocatalysis and biomedicine.On the one hand,the use of inexhaustible solar energy for fossil fuel production and environmental remediation is the most ideal solution by artificial photocatalysis.However,optical responsive range of semiconductor nanomaterials is mostly limited to the region from ultraviolet light to visible light,while the NIR which accounts for 50%of the sunlight is rarely used effectively,thus limiting the conversion of sunlight.On the other hand,since the absorption of NIR by biological tissues is weak,the NIR is also called as the biological tissue optical window.The development of a nano-therapeutic system based on NIR responsive nanomaterials can effectively avoid the background interference of biological tissues and achieve deep treatment.Therefore,it is of far-reaching significance to develop NIR I-Ⅱresponse semiconductor materials.Based on this,we utilize a double-doping strategy in which both oxygen vacancies and boron atoms dope successfully prepared ZrO_2-x-B,which can respond to NIR I-Ⅱ.And we also study its application in the field of photocatalysis and phototherapy.The main contents are as follows:Chapter 1:Outlines the current preparation methods of NIR-responsive semiconductor materials and their applications in photocatalysis and phototherapy,and puts forward the ideas and research significance of this paper.Chapter 2:A NIR-responsive ZrO_2-x-B was prepared by introducing oxygen vacancies and boron atoms into ZrO₂.The prepared samples were systematically characterized by X-ray powder diffraction,transmission electron microscopy,X-ray photoelectron spectroscopy,UV-vis-NIR diffuse reflectance spectroscopy.The electronic structure of the doped samples was investigated by DFT,and the effects of the introduction of oxygen vacancies and boron atoms on the NIR response was analyzed.The photocatalytic degradation of rhodamine B under UV,visible and NIR light was studied.The photocatalytic mechanism under different wavelengths was investigated by free radical trapping and free radical inhibition experiments.This study provides an inspiring example for the preparation of NIR-responsive semiconductors,and opens a new path for design and fabrication of novel NIR-responsive energy conversion materials.Chapter 3:ZrO_2-x-B nanoparticles were further modified with biopolysaccharide hyaluronic acid to achieve targeted photothermal/photodynamic therapy based on tumor microenvironment response.The hyaluronic acid-modified nanoparticles can specifically bind to the overexpressed CD44 receptor on the surface of tumor cells to achieve targeting.The uptake of the nanoparticles by tumor cells is significantly enhanced compared to normal cells.At the same time,the activation reaction of ZrO₂-_x-B and H₂O₂ in the tumor microenvironment and the effect of enhancing photodynamic therapy is realized in the tumor cells.In vivo and in vitro experiments showed that the biopolysaccharide-modified ZrO_2-x-B achieved the targeting CD44 receptor expressing tumor cells and enhanced photothermal/photodynamic synergistic therapy.This study provides a new material for biomedical field.