【作者】 何佳；

【导师】 吴尧；

【作者基本信息】 四川大学 ， 化学， 2023， 博士

【摘要】 金属有机框架材料（Metal-organic frameworks,MOFs）和共价有机框架材料（Covalent-organic frameworks,COFs）具有高比表面积、高孔隙率、结构可设计、易于功能化等特点,近年来在储能、储气、分离、催化、传感等领域发展迅猛。随着对框架材料的研究与应用的拓展,其单一的活性位点、刚性的结构和单调的孔径分布等已无法满足迅速增长的应用需求。可喜的是,无机纳米片,纳米粒子和缺陷结构的引入将赋予框架材料丰富的活性位点、超顺磁性以及分级多孔结构,有望通过多重亲和作用和高传质效率来实现材料与客体分子之间更高效的接触。然而,传统方法制备框架材料条件苛刻、耗能高、耗时长、效率低、对产物不可控,限制了研究人员对材料的进一步优化。因此,开发简便、高效且可控的合成方法,定向制备框架复合材料,对材料科学的发展以及拓展其应用均具有深远的意义。在本文中,我们开发了简便、节能、可控的合成方法来制备不同形貌COF材料,并进一步用于水体中染料分离应用;开发了简便高效的在二维纳米片上原位生长MOFs的新策略,用于磷酸化肽段的特异性富集。主要研究工作摘要如下:（1）为了解决传统方法制备COFs条件苛刻、操作复杂以及依赖大量有机溶剂的问题,我们首次提出在以水为溶剂,在常温常压下制备形貌可控的COF材料的方法。引入不同极性的助溶剂,可控调节COFs的形貌从光滑球形到树莓状再到海胆状。此外,改变醋酸水溶液的加入方式,可实现对COF球粒径的控制。（2）常温常压下,我们通过界面结晶法在水-二氯甲烷界面处制备出形貌和厚度可控的COF膜。其中,在液-液界面快速形成无定形聚合物膜,可有效控制醋酸的扩散和结构重排,获得具有高结晶度的平整COF膜。通过控制生长过程,自立COF膜的厚度可从50 nm调节到1μm。所获得的COF膜具有高表面积(378 m² g^-1)、丰富的介孔结构（2.17 nm）,这意味着其与染料分子充分的接触。此外,COF膜固有的共轭苯环结构使其具有通过π-π相互作用吸附芳香苯环染料（铬黑T和玫瑰红）的潜力。结合静电相互作用和分子尺寸的影响,COF膜对这两种染料展现出优异的吸附性能。（3）除了对共价有机框架（COFs）材料的可控制备及应用的研究,我们还对金属有机框架（MOFs）材料的制备及应用进行了深入的探索和研究。利用介质阻挡放电（DBD）技术,我们在室温和大气压下,一锅合成Oxid-Ti₃C₂T_x/UIO-66-NH₂复合材料,实现多组分协同富集磷酸肽段。相较于传统溶剂热法,DBD技术能够在开放体系中实现Ti₃C₂T_x纳米片上原位生长Zr-MOF,反应时间由原来的12-24小时缩短为40分钟。在此过程中,Ti₃C₂T_x也被部分氧化,实现无需额外钛源制备TiO₂纳米粒子,为在Mxenes上快速、均匀地原位生长TiO₂以及高能耗MOFs提供了新的途径。由于复合材料固有的亲水性和丰富的活性位点（Zr-O簇、金属活性位点和TiO₂纳米粒子）,Oxid-Ti₃C₂T_x/UIO-66-NH₂展现出低检测限(0.1 fmolμL^-1)和较为理想的特异性（α-酪蛋白:BSA=1:100）。同时,Oxid-Ti₃C₂T_x/UIO-66-NH₂复合材料在复杂生物样品（如脱脂牛奶、人唾液和血清）中也展现出良好的应用潜力。（4）上述Oxid-Ti₃C₂T_x/UIO-66-NH₂主要利用MOAC策略富集磷酸化肽,单一富集策略使得复合材料倾向于对单磷酸化肽的富集,导致部分多磷酸化肽信息的缺失;此外在材料后处理以及富集过程中依赖高速离心进行产物回收,高转速会对所富集生物样本产生影响,且造成一定程度的产物损失。本章节联合DBD技术和溶剂热法,可控制备磁性分级多孔GO/UIO-66/Fe₃O₄复合材料。与上一个工作类似,二维氧化石墨烯与零维UIO-66纳米粒子巧妙结合,大大提高所得复合材料的比表面积以及与磷酸化肽段接触的活性位点,进一步提升对磷酸化肽段的富集效果。不同的是,DBD技术在保障高效定向生长UIO-66的基础上,通过控制氧化石墨烯（GO）和反应时间来实现大量缺陷的引入。这不但赋予复合材料分级多孔的结构,而且暴露一定量的Zr⁴⁺,协同UIO-66固有的Zr-O以及Fe₃O₄中的Fe-O,实现IMAC、MOAC双策略协同全面富集（18条多磷酸肽和20条单磷酸化肽）。最后,超顺磁性Fe₃O₄纳米粒子的引入不仅丰富了亲和位点（Fe-O、-NH₂）,而且赋予了复合材料超高的磁响应性,极大地简化了富集和分离过程,避免了富集时传统高速离心对捕获的生物样品的影响。更多还原

【Abstract】 Metal organic frameworks（MOFs）and covalent organic frameworks（COFs）have developed rapidly in recent years in the fields of energy storage,gas storage,separation,catalysis,and sensing due to their ultra-high specific surface area,porosity,ease of post modification and structural designability.However,with the in-depth research and application of frameworks,the problems of single active sites,rigid structure,and monotonous pore size distribution have been unable to meet the growing application requirements.Fortunately,the introduction of inorganic nanosheets,nanoparticles,and defective structures will endow the frameworks with abundant active sites and hierarchical porous structures,facilitating more efficient contact between the frameworks and guest molecules（high mass transfer efficiency,multiple affinity）.However,traditional methods for synthesis frameworks have harsh conditions,high energy consumption,time consumption,low efficiency,and uncontrollable products,which limits the further optimization of materials.Therefore,developing fast,simple,efficient,and controllable synthesis methods to directionally synthesize framework composites has far-reaching significance for the development of material science and the expansion of its applications.In our works,simple,energy-saving,and controllable methods for preparing COFs with different morphologies has been developed based on the above issues,and further applied to separate dyes from water;Simple and efficient methods for in situ growth of MOFs on two-dimensional nanosheets has been developed for the specific enrichment of phosphorylated peptides.The main research works are summarized as follows:（1）In order to overcome the problems of harsh conditions,complex operations,and heavy reliance on organic solvents in traditional methods for preparing COFs,a new method synthesizing COFs with controllable morphology in aqueous phase under room temperature and pressure was proposed for the first time.The introduction of different polar cosolvents can controllably adjust the morphology of COFs from smooth sphere to raspberry and sea urchin.Meanwhile,the particle size and crystallinity of COF nanoparticles can be controlled by changing the addition method of acetic acid aqueous solution.（2）COF membrane with controllable morphology and thickness was prepared at CH₂Cl₂-H₂O interface by interfacial crystallization method.The rapid formation of amorphous polymer films at the liquid-liquid interface can surly slown down the diffusion of acetic acid（HAc）and effectively control structural rearrangement COFs to obtain flat COF membranes with high crystallinity.In addition,by controlling reaction time,the thickness of the self-supporting COF membranes can be adjusted from 50 nm to 1μm.The obtained COF membranes featured with high surface area(378 m² g^-1)and mesoporous structure（2.17 nm）,meaning full contact with dye molecules.In addition,the inherent phenyl structures represent that COF membranes has the potential to adsorb aromatic benzene ring（Chrome black T and Bengal Rose）dyes throughπ-πinteractions.And combined with electrostatic interaction,molecular size effects,COF membranes exhibit excellent adsorption properties for Chrome black T and Bengal Rose during the application.（3）In addition to studying the controllable synthesis and application of COFs,we have also conducted in-depth exploration on the synthesis and application of MOFs.Through dielectric barrier discharge（DBD）technology,Oxid-Ti₃C₂T_x/UIO-66-NH₂was synthesized in one pot under mild conditions to achieve multicomponent synergistic enrichment of phosphate peptides.Compared to traditional methods,DBD technology can achieve in-situ growth of Zr-MOF on Ti₃C₂T_x nanosheets in an open system,reducing the reaction time from 12-24 hours to 40 minutes.During this process,Ti₃C₂T_x is also partially oxidized,introducing TiO₂ nanoparticles without additional titanium sources,which provides a new way to grow TiO₂ rapidly and uniformly and high-energy consuming MOFs in situ on Mxenes.The obtained Oxid-Ti₃C₂T_x/UIO-66-NH₂ owned inherent hydrophilicity and abundant active sites（Zr-O clusters,metal active sites,and TiO₂ nanoparticles）,exhibiting a low detection limit(0.1 fmolμL^-1)and satisfactory specificity（1:100）duringα-casein digest treament.At the same time,the composites also performe well when applied to treat complex biological samples such as skimmed milk,human serum,and saliva,providing insights for the practice of MXene/MOF composites in biomolecular recognition field.（4）The above Oxid Ti₃C₂T_x/UIO-66-NH₂ monotonically utilizes the MOAC strategy to enrich phosphorylated peptides and tends to enrich monophosphorylated peptides,leading to a certain lack of information on polyphosphorylated peptides;In addition,the post-processing of materials and the materials recovery during enrichment rely on high-speed centrifugation,which inevitably leads to a certain degree of product loss and the impact of high-speed centrifugation on the enriched biological samples.This chapter combines DBD technology and solvothermal method to controllable synthesize GO/UIO-66/Fe₃O₄ with superparamagnetism and graded porous structure.Like previous work,the ingenious combination of two-dimensional graphite oxide and zero dimensional UIO-66 nanoparticle greatly improves the specific surface area and the active sites contacting with the phosphorylated peptide segment.Specially,based on UIO-66 grown oriently,many defects were introduced into composite by DBD technology through controlling the amount of GO,HAc and the reaction time.This not only endows the composite with graded porous structures,but also exposes a certain amount of Zr⁴⁺,synergizing with the inherent Zr-O of UIO-66 and Fe-O of Fe₃O₄,achieving efficient enrichment of 18 polyphosphate peptides and 20 monophosphate peptides through IMAC and MOAC strategies.The introduction of superparamagnetism Fe₃O₄ nanoparticles not only enriched the affinity sites（Fe-O）,but also endows the composite with ultra-high magnetic responsiveness,which greatly simplifying the enrichment and separation process and avoiding the impact of traditional high-speed centrifugation on captured biological samples.更多还原