CN107413387B - A kind of preparation method of manganese-doped titanium dioxide nanofiber material - Google Patents

A kind of preparation method of manganese-doped titanium dioxide nanofiber material Download PDF

Info

Publication number
CN107413387B
CN107413387B CN201710767439.0A CN201710767439A CN107413387B CN 107413387 B CN107413387 B CN 107413387B CN 201710767439 A CN201710767439 A CN 201710767439A CN 107413387 B CN107413387 B CN 107413387B
Authority
CN
China
Prior art keywords
manganese
titanium dioxide
short peptide
solution
nanofiber material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201710767439.0A
Other languages
Chinese (zh)
Other versions
CN107413387A (en
Inventor
王生杰
徐海
杜明轩
张董秀
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China University of Petroleum East China
Original Assignee
China University of Petroleum East China
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by China University of Petroleum East China filed Critical China University of Petroleum East China
Priority to CN201710767439.0A priority Critical patent/CN107413387B/en
Publication of CN107413387A publication Critical patent/CN107413387A/en
Application granted granted Critical
Publication of CN107413387B publication Critical patent/CN107413387B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/26Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24
    • B01J31/38Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24 of titanium, zirconium or hafnium
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/30Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B01J35/39Photocatalytic properties
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/50Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
    • B01J35/58Fabrics or filaments
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/30Treatment of water, waste water, or sewage by irradiation
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/30Organic compounds
    • C02F2101/308Dyes; Colorants; Fluorescent agents
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2305/00Use of specific compounds during water treatment
    • C02F2305/10Photocatalysts

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Toxicology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Catalysts (AREA)

Abstract

本发明提供了一种锰掺杂二氧化钛纳米纤维材料的制备方法,属于光催化材料技术领域,对环境中的有机污染物具有较高的光催化降解效率。所述制备方法,包括:将两亲性阳离子短肽分散在水中,超声分散,调节溶液pH值,置于室温放置一周以上,得到短肽自组装体溶液;将二氧化钛前驱体、高锰酸钾溶液和硝酸锰溶液依次加入到所述两亲性短肽自组装溶液中,涡旋混匀,在室温反应后,离心得到灰褐色沉淀;将灰褐色沉淀洗涤后加热,除去短肽模板,得到锰掺杂二氧化钛纳米纤维材料。本发明可用于制备锰掺杂二氧化钛纳米纤维材料。

Figure 201710767439

The invention provides a preparation method of a manganese-doped titanium dioxide nanofiber material, which belongs to the technical field of photocatalytic materials and has high photocatalytic degradation efficiency for organic pollutants in the environment. The preparation method includes: dispersing the amphiphilic cationic short peptide in water, dispersing by ultrasonic, adjusting the pH value of the solution, and placing it at room temperature for more than a week to obtain a short peptide self-assembly solution; dispersing a titanium dioxide precursor, potassium permanganate The solution and the manganese nitrate solution are sequentially added to the amphiphilic short peptide self-assembly solution, vortexed and mixed, and after the reaction at room temperature, centrifugation is performed to obtain a gray-brown precipitate; the gray-brown precipitate is washed and heated to remove the short peptide template to obtain Manganese-doped titanium dioxide nanofibrous material. The invention can be used for preparing manganese-doped titanium dioxide nanofiber material.

Figure 201710767439

Description

一种锰掺杂二氧化钛纳米纤维材料的制备方法A kind of preparation method of manganese-doped titanium dioxide nanofiber material

技术领域technical field

本发明涉及光催化材料技术领域,尤其涉及一种锰掺杂二氧化钛纳米纤维材料的制备方法。The invention relates to the technical field of photocatalytic materials, in particular to a preparation method of a manganese-doped titanium dioxide nanofiber material.

背景技术Background technique

二氧化钛具有无毒、廉价、活性高、耐紫外光辐射、耐强氧化剂以及耐酸碱等特点,是一类极具吸引力的多功能半导体材料,在光子器件、太阳能电池和光催化等领域具有巨大的应用前景。但氧化钛的固有禁带宽度过宽(锐钛矿相禁带宽度为3.0eV,金红石相禁带宽度为3.2eV),使其只能被波长小于387nm的紫外光(在太阳光中占比小于5%)激发,而对于占比50%以上的可见光并不敏感。过低的光利用率严重地限制了氧化钛的应用效果。为此,科研工作者进行了大量的研究工作,调整氧化钛的禁带宽度,将其光响应范围向可见光区扩展。目前,国内外关于氧化钛光催化剂的主要改性技术包括离子掺杂(参见Mao Y.等,《德国应用化学》,2014,53:10485)、表面贵金属沉积(Yun J.等,《美国化学会应用材料于界面》,2015,7:2055)、半导体复合(Thapa A.等,《纳米研究》,2014,7:1154)以及金属络合物和染料光敏化(Altin I.等,《淡化与水处理》,2016,57:16196)。其中,向氧化钛相中掺杂其它元素,使其吸收边界向着可见光区拓展被认为是一种高效且简单易行的方法,受到了众多科研者的关注。Titanium dioxide is non-toxic, inexpensive, highly active, resistant to ultraviolet light radiation, strong oxidants, and acid and alkali resistant. application prospects. However, the inherent forbidden band width of titanium oxide is too wide (3.0 eV for anatase and 3.2 eV for rutile), so that it can only be used by ultraviolet light with a wavelength less than 387 nm (the proportion of sunlight in sunlight). less than 5%) excitation, but not sensitive to visible light accounting for more than 50%. The low light utilization rate severely limits the application effect of titanium oxide. To this end, researchers have carried out a lot of research work to adjust the forbidden band width of titanium oxide and expand its photoresponse range to the visible light region. At present, the main modification technologies for titanium oxide photocatalysts at home and abroad include ion doping (see Mao Y. et al., "German Applied Chemistry", 2014, 53: 10485), surface noble metal deposition (Yun J. et al., "American Chemistry"). will apply materials to interfaces", 2015, 7: 2055), semiconductor composites (Thapa A. et al., "Nano Research", 2014, 7: 1154) and metal complexes and dye photosensitization (Altin I. et al., "Dilute" and Water Treatment, 2016, 57:16196). Among them, doping other elements into the titanium oxide phase to expand the absorption boundary to the visible light region is considered to be an efficient and simple method, which has attracted the attention of many researchers.

氧化钛的掺杂改性包括非金属离子掺杂(例如,碳、氮、硫、氟等)和金属离子掺杂(如铁、钴、铜、钒、镓等)。其中,非金属离子在主相中一般作为阴离子存在,而金属离子则作为阳离子存在于氧化钛中。相比非金属掺杂需要复杂的过程控制(例如通过焰火反应进行阴离子掺杂),过渡金属阳离子掺杂较为简单,被认为是一种十分具有前景的掺杂手段。而在众多的过渡金属元素中,多价态金属如锰、铁已被证实能够增强氧化钛对可见光的吸收,锰离子掺杂进入金红石相氧化钛后,在收缩的禁带间隙中引入弯曲的中间能带,可构成电子能带结构的显著改变。这种弯曲的中间能带(IB)在不同波长光吸收过程中将作为“垫脚石”来有效参与价带的电子传递,从而造成材料光吸收的显著红移。Doping modifications of titanium oxide include non-metal ion doping (eg, carbon, nitrogen, sulfur, fluorine, etc.) and metal ion doping (eg, iron, cobalt, copper, vanadium, gallium, etc.). Among them, non-metal ions generally exist as anions in the main phase, while metal ions exist as cations in titanium oxide. Compared with non-metal doping, which requires complex process control (such as anion doping by pyrotechnic reaction), transition metal cation doping is relatively simple and is considered to be a very promising doping method. Among the many transition metal elements, multivalent metals such as manganese and iron have been proved to enhance the absorption of visible light by titanium oxide. The intermediate energy band can constitute a significant change in the electronic energy band structure. This curved intermediate band (IB) will act as a "stepping stone" to efficiently participate in the electron transport of the valence band during light absorption at different wavelengths, resulting in a significant red shift in the material's light absorption.

作为光催化材料,光催化性能除了与其光吸收能力有关之外,还受控于其光生电子和空穴的分离和传输性质。一维纳米材料具有一定的量子尺寸效应,能够提高光催化反应的量子产率;在光学性质上,一维纳米材料具有较大的纵横比,能显著增强光的散射和吸收;在微观结构上,一维纳米材料具有较小的电子迁移路径,有利于电子的传输,延缓电子的覆灭。因此,通过制备结构可控的锰掺杂二氧化钛纳米纤维材料,有望获得较高的太阳光利用效率和光催化转化效果,并在有机污染物的处理、光电/光化学转化等领域获得应用。As a photocatalytic material, the photocatalytic performance is not only related to its light absorption ability, but also controlled by its photogenerated electron and hole separation and transport properties. One-dimensional nanomaterials have a certain quantum size effect, which can improve the quantum yield of photocatalytic reactions; in terms of optical properties, one-dimensional nanomaterials have a large aspect ratio, which can significantly enhance the scattering and absorption of light; in terms of microstructure , One-dimensional nanomaterials have a small electron migration path, which is conducive to the transmission of electrons and delays the destruction of electrons. Therefore, by preparing manganese-doped TiO2 nanofibers with controllable structure, it is expected to obtain higher solar light utilization efficiency and photocatalytic conversion effect, and be applied in the treatment of organic pollutants, photoelectric/photochemical conversion and other fields.

发明内容SUMMARY OF THE INVENTION

本发明的目的在于提供一种锰掺杂二氧化钛纳米纤维材料的制备方法,能够提高二氧化钛对太阳光的利用率和光催化效率,从而提高光催化转化效率和有机污染物的降解效果。The purpose of the present invention is to provide a preparation method of manganese-doped titanium dioxide nanofiber material, which can improve the utilization rate and photocatalytic efficiency of titanium dioxide for sunlight, thereby improving the photocatalytic conversion efficiency and the degradation effect of organic pollutants.

本发明提供了一种锰掺杂二氧化钛纳米纤维材料的制备方法,包括:The invention provides a preparation method of manganese-doped titanium dioxide nanofiber material, comprising:

将两亲性阳离子短肽分子超声分散于水中,调节溶液pH值,置于室温放置1周以上,得到两亲性短肽的自组装溶液;The amphiphilic cationic short peptide molecules are dispersed in water by ultrasonic wave, the pH value of the solution is adjusted, and the solution is placed at room temperature for more than 1 week to obtain a self-assembly solution of the amphiphilic short peptide;

将二氧化钛前驱体、高锰酸钾溶液和硝酸锰溶液依次加入到所述两亲性短肽自组装溶液中,涡旋混匀,在室温反应10-24小时后,离心得到灰褐色沉淀,洗涤沉淀,在300-500℃加热2-10小时,以除去短肽模板,得到锰掺杂二氧化钛纳米纤维材料;The titanium dioxide precursor, the potassium permanganate solution and the manganese nitrate solution were added to the self-assembly solution of the amphiphilic short peptide in turn, vortexed and mixed, and after reacting at room temperature for 10-24 hours, centrifuged to obtain a gray-brown precipitate, and washed Precipitation and heating at 300-500°C for 2-10 hours to remove short peptide templates to obtain manganese-doped titanium dioxide nanofiber materials;

其中,所述两亲性阳离子短肽分子的疏水单元由3-6个亮氨酸、异亮氨酸、甘氨酸、缬氨酸组成,亲水头基由1-2个赖氨酸、组氨酸、精氨酸组成,在水溶液中能形成纳米纤维结构。Wherein, the hydrophobic unit of the amphiphilic cationic short peptide molecule is composed of 3-6 leucine, isoleucine, glycine and valine, and the hydrophilic head group is composed of 1-2 lysine, histidine It is composed of acid and arginine, and can form nanofibrous structure in aqueous solution.

可选的,所述二氧化钛前驱体选自钛酸正丁酯、钛酸异丙酯、二(2-羟基丙酸)二氢氧化二铵合钛中的至少一种。Optionally, the titanium dioxide precursor is selected from at least one of n-butyl titanate, isopropyl titanate, and diammonium bis(2-hydroxypropionic acid)dihydroxide.

优选的,所述两亲性短肽的浓度为0.5-10mmol L-1,二氧化钛前驱体的浓度为1-10mmol L-1,高锰酸钾的浓度为0.001-0.1mmol L-1,硝酸锰的浓度为0.0015-0.15mmol L-1Preferably, the concentration of the amphiphilic short peptide is 0.5-10 mmol L -1 , the concentration of the titanium dioxide precursor is 1-10 mmol L -1 , the concentration of potassium permanganate is 0.001-0.1 mmol L -1 , the concentration of manganese nitrate is 0.001-0.1 mmol L -1 , The concentration is 0.0015-0.15 mmol L -1 .

优选的,将两亲性短肽超声分散于水中后,溶液的pH值调节到5-9的范围内。Preferably, after ultrasonically dispersing the amphiphilic short peptide in water, the pH value of the solution is adjusted to a range of 5-9.

可选的,所述洗涤处理具体包括交替使用纯水、乙醇清洗所述灰褐色沉淀。Optionally, the washing treatment specifically includes alternately using pure water and ethanol to wash the gray-brown precipitate.

优选的,所述离心处理的转速为5000-10000rpm,时间为20-60分钟。Preferably, the rotational speed of the centrifugal treatment is 5000-10000 rpm, and the time is 20-60 minutes.

本发明的另一方面提供了一种如上述技术方案中任一项所述的锰掺杂二氧化钛纳米纤维材料制备方法所制备得到的锰掺杂二氧化钛纳米纤维材料。Another aspect of the present invention provides a manganese-doped titanium dioxide nanofiber material prepared by the method for preparing a manganese-doped titanium dioxide nanofiber material according to any one of the above technical solutions.

本发明的再一方面提供了一种如上述技术方案所述的锰掺杂二氧化钛纳米纤维材料在光催化降解有机污染物中的应用。Another aspect of the present invention provides an application of the manganese-doped titanium dioxide nanofiber material as described in the above technical solution in photocatalytic degradation of organic pollutants.

本发明提供了一种锰掺杂二氧化钛纳米纤维材料的制备方法,相比于现有技术而言,该方法在两亲性短肽自组装纳米纤维的存在下,通过有机模板的分子识别、催化作用诱导二氧化钛在模板表面成核、生长,同时通过肽模板调控的高锰酸钾与硝酸锰的氧化还原反应在二氧化钛中引入锰离子,最终形成锰掺杂二氧化钛纳米纤维材料。由于是通过分子识别导向的掺杂,因此在材料的掺杂位点、掺杂结构和组成方面具有明显优势。通过本方法所制备得到的锰掺杂二氧化钛纳米纤维材料,其禁带宽度可达到1.55eV,在可见光区的吸收显著增强。同时,锰离子的掺杂以及一维纳米结构的存在大大提高了载流子的分离和传输效率,其光电转化和传输效率大大增加。通过对模型有机污染物的降解实验表明,与商业化的纳米二氧化钛光催化剂P25相比,本发明所制备的锰掺杂二氧化钛纳米纤维材料的光催化性能明显提高,且避免了聚集引起的催化位点减少和催化效率降低,循环使用的稳定性大大提高。该方法在室温、近中性的水溶液条件下制备得到了锰掺杂二氧化钛纳米纤维材料,整个合成过程具有简单、节能、环保的优点。The invention provides a preparation method of manganese-doped titanium dioxide nanofiber material. Compared with the prior art, the method can recognize and catalyze the molecular recognition and catalysis of organic templates in the presence of amphiphilic short peptide self-assembled nanofibers. The action induces the nucleation and growth of titanium dioxide on the surface of the template, and at the same time, manganese ions are introduced into the titanium dioxide through the redox reaction of potassium permanganate and manganese nitrate regulated by the peptide template, and finally the manganese-doped titanium dioxide nanofiber material is formed. Since the doping is guided by molecular recognition, it has obvious advantages in the doping site, doping structure and composition of the material. The manganese-doped titanium dioxide nanofiber material prepared by the method has a forbidden band width of 1.55 eV, and the absorption in the visible light region is significantly enhanced. At the same time, the doping of manganese ions and the existence of one-dimensional nanostructures greatly improve the separation and transport efficiency of carriers, and its photoelectric conversion and transport efficiency are greatly increased. The degradation experiments of model organic pollutants show that, compared with the commercial nano-TiO2 photocatalyst P25, the photocatalytic performance of the manganese-doped TiO2 nanofiber material prepared by the present invention is obviously improved, and the catalytic sites caused by aggregation are avoided. Point reduction and catalytic efficiency are reduced, and the stability of recycling is greatly improved. The method prepares the manganese-doped titania nanofiber material under the condition of room temperature and near-neutral aqueous solution, and the whole synthesis process has the advantages of simplicity, energy saving and environmental protection.

附图说明Description of drawings

图1为本发明实施例所制备得到的锰掺杂二氧化钛纳米纤维材料的透射电子显微镜照片;Fig. 1 is the transmission electron microscope photograph of the manganese-doped titanium dioxide nanofiber material prepared by the embodiment of the present invention;

图2为本发明实施例所制备得到的锰掺杂二氧化钛纳米纤维材料和纯二氧化钛纳米纤维材料的紫外-可见吸收光谱;Fig. 2 is the ultraviolet-visible absorption spectrum of manganese-doped titania nanofiber material and pure titania nanofiber material prepared in the embodiment of the present invention;

图3A本发明实施例所制备得到的锰掺杂二氧化钛纳米纤维材料和纯二氧化钛纳米纤维材料的Ti 2p X射线光电子能谱;Fig. 3A Ti 2p X-ray photoelectron spectrum of manganese-doped titania nanofiber material and pure titania nanofiber material prepared in the embodiment of the present invention;

图3B本发明实施例所制备得到的锰掺杂二氧化钛纳米纤维材料的Mn 2p X射线光电子能谱;3B Mn 2p X-ray photoelectron spectrum of the manganese-doped titania nanofiber material prepared in the embodiment of the present invention;

图4为本发明实施例所制备得到的锰掺杂二氧化钛纳米纤维材料和纯二氧化钛纳米纤维材料的光电流响应曲线;Fig. 4 is the photocurrent response curve of manganese-doped titania nanofiber material and pure titania nanofiber material prepared in the embodiment of the present invention;

图5A为本发明实施例所制备得到的锰掺杂二氧化钛纳米纤维材料和商业化二氧化钛纳米材料的光催化亚甲基蓝降解曲线;5A is the photocatalytic methylene blue degradation curve of the manganese-doped titania nanofiber material and the commercial titania nanomaterial prepared in the embodiment of the present invention;

图5B为本发明实施例所制备得到的锰掺杂二氧化钛纳米纤维材料和商业化二氧化钛纳米材料的光催化罗丹明B降解曲线;5B is the photocatalytic Rhodamine B degradation curve of the manganese-doped titania nanofiber material and the commercial titania nanomaterial prepared in the embodiment of the present invention;

图6A为锰掺杂二氧化钛纳米纤维材料循环光催化降解亚甲基蓝的浓度-反应时间曲线;6A is a concentration-reaction time curve of cyclic photocatalytic degradation of methylene blue by manganese-doped titania nanofiber materials;

图6B为商业化二氧化钛(P25)循环光催化降解亚甲基蓝的浓度-反应时间曲线。Figure 6B is the concentration-reaction time curve of cyclic photocatalytic degradation of methylene blue for commercial titanium dioxide (P25).

具体实施方式Detailed ways

下面将对本发明实施例中的技术方案进行清楚、完整地描述,显然,所描述的实施例仅仅是本发明的一部分实施例,而不是全部的实施例。基于本发明中的实施例,本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其它实施例,都属于本发明保护的范围。The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

本发明实施例提供了一种锰掺杂二氧化钛纳米纤维材料的制备方法,包括:An embodiment of the present invention provides a method for preparing a manganese-doped titanium dioxide nanofiber material, comprising:

S1:将两亲性阳离子短肽分子超声分散于水中,调节溶液pH值,置于室温放置1周以上,得到两亲性阳离子短肽的自组装模板S1: ultrasonically disperse the amphiphilic cationic short peptide molecule in water, adjust the pH value of the solution, and place it at room temperature for more than 1 week to obtain the self-assembly template of the amphiphilic cationic short peptide

在本步骤中,利用两亲性阳离子短肽自组装构建一维有机模板。具体的,将两亲性阳离子短肽超声分散于水中后,将体系pH值调节至近中性,静止放置一周以上,得到两亲性短肽的自组装溶液。在本步骤中,因为采用的是两亲性阳离子短肽,近中性的pH值能够使阳离子氨基酸残基的侧链质子化,提供静电作用的同时稳定所形成的自组装结构,而且,近中性的pH环境也有利于获得合适的二氧化钛生成速率。In this step, a one-dimensional organic template is constructed by self-assembly of amphiphilic cationic short peptides. Specifically, after ultrasonically dispersing the amphiphilic cationic short peptide in water, the pH value of the system is adjusted to near neutral, and it is left to stand for more than a week to obtain a self-assembly solution of the amphiphilic short peptide. In this step, since an amphiphilic cationic short peptide is used, the near-neutral pH value can protonate the side chain of the cationic amino acid residue, provide electrostatic effect and stabilize the self-assembled structure formed, and the near-neutral pH value can stabilize the self-assembled structure formed. Neutral pH environment is also beneficial to obtain suitable titanium dioxide formation rate.

S2:将二氧化钛前驱体、高锰酸钾溶液和硝酸锰溶液依次加入到所述两亲性短肽自组装溶液中,涡旋混匀,在室温反应10-24小时后,离心得到灰褐色沉淀,洗涤沉淀,在300-500℃加热2-10小时,以除去短肽模板,得到锰掺杂二氧化钛纳米纤维材料。S2: adding titanium dioxide precursor, potassium permanganate solution and manganese nitrate solution to the amphiphilic short peptide self-assembly solution in sequence, vortexing and mixing, reacting at room temperature for 10-24 hours, and centrifuging to obtain a gray-brown precipitate , washed the precipitate, and heated at 300-500 °C for 2-10 hours to remove the short peptide template to obtain a manganese-doped titanium dioxide nanofiber material.

在本步骤中,为了得到锰掺杂的二氧化钛纳米纤维材料,依次将二氧化钛前驱体、高锰酸钾溶液和硝酸锰溶液加入到两亲性短肽组装体溶液中,使得二氧化钛的生成以及高锰酸钾和硝酸锰的氧化还原反应在两亲性短肽自组装模板的调控下进行。可以理解的是,反应时间视反应充分程度而定,可以为10、12、14、16、18、20、22、24小时不等或上述范围内的其它任一点值均可。对生成的沉淀进行洗涤是为了除去未反应完全的二氧化钛前驱体、高锰酸钾和硝酸锰。加热是为了除去短肽模板并形成相应的晶体结构,加热温度和加热时间是相互依赖的,本领域的技术人员可以在上述范围内自行调节,温度高则可以时间短,但加热温度太高会使材料的结构和形貌发生改变,温度太低难以达到除去短肽模板的目的。In this step, in order to obtain manganese-doped titanium dioxide nanofiber material, titanium dioxide precursor, potassium permanganate solution and manganese nitrate solution are sequentially added to the amphiphilic short peptide assembly solution, so that the formation of titanium dioxide and high manganese The redox reactions of potassium phosphate and manganese nitrate proceed under the regulation of amphiphilic short peptide self-assembly templates. It can be understood that the reaction time depends on the sufficiency of the reaction, and can be 10, 12, 14, 16, 18, 20, 22, 24 hours or any other value within the above range. The resulting precipitate is washed to remove unreacted titanium dioxide precursor, potassium permanganate and manganese nitrate. The purpose of heating is to remove the short peptide template and form the corresponding crystal structure. The heating temperature and heating time are interdependent, and those skilled in the art can adjust it within the above range. If the temperature is high, the time can be short, but the heating temperature is too high. The structure and morphology of the material are changed, and the temperature is too low to achieve the purpose of removing the short peptide template.

在本发明的一实施例中,所述两亲性阳离子短肽的疏水单元由3-6个亮氨酸、异亮氨酸、甘氨酸、缬氨酸组成,亲水头基由1-2个赖氨酸、组氨酸、精氨酸组成,在水溶液中能形成纳米纤维结构。在本实施例中,由亲水的氨基酸残基和疏水的氨基酸残基共同组成两亲性阳离子短肽,氨基酸的类型、数量和位置决定了短肽自组装体的形态,即模板的形貌和结构,同时对形成的锰掺杂二氧化钛纳米纤维材料的结构和性质具有重要影响。短肽模板表面的亲水头基除了吸引相反电荷的无机物前驱体在其附近聚集外,对二氧化钛的形成具有重要的催化作用,以及对其后锰离子、二氧化钛在纳米纤维材料中的结构重排起着重要的引导作用。In an embodiment of the present invention, the hydrophobic unit of the amphiphilic cationic short peptide is composed of 3-6 leucine, isoleucine, glycine, and valine, and the hydrophilic head group is composed of 1-2 It is composed of lysine, histidine and arginine, and can form nanofibrous structure in aqueous solution. In this example, amphiphilic cationic short peptides are composed of hydrophilic amino acid residues and hydrophobic amino acid residues. The type, quantity and position of amino acids determine the shape of the short peptide self-assembly, that is, the shape of the template. and structure, while having a significant impact on the structure and properties of the formed manganese-doped titania nanofibrous materials. In addition to attracting the oppositely charged inorganic precursors to aggregate in the vicinity of the hydrophilic head group on the surface of the short peptide template, it has an important catalytic effect on the formation of titanium dioxide, as well as on the subsequent structure of manganese ions and titanium dioxide in nanofiber materials. The row plays an important guiding role.

在本发明的一实施例中,所述二氧化钛前驱体选自钛酸正丁酯、钛酸异丙酯、二(2-羟基丙酸)二氢氧化二铵合钛中的至少一种。在本实施例中,由于二氧化钛前驱体的水解速率不同,选择不同的前驱体可以调节二氧化钛的生成速率,从而获得具有适宜成核速率和生长速率的反应体系,以制备具有设计结构的锰掺杂二氧化钛纳米纤维材料。In an embodiment of the present invention, the titanium dioxide precursor is selected from at least one of n-butyl titanate, isopropyl titanate, and diammonium bis(2-hydroxypropionic acid)dihydroxide. In this example, due to the different hydrolysis rates of titania precursors, selecting different precursors can adjust the generation rate of titania, so as to obtain a reaction system with suitable nucleation rate and growth rate to prepare manganese-doped manganese with a designed structure Titanium dioxide nanofiber material.

在本发明的一实施例中,所述两亲性短肽的浓度0.5-10mmol L-1,二氧化钛前驱体的浓度为1-10mmol L-1,高锰酸钾的浓度为0.001-0.1mmol L-1,硝酸锰的浓度为0.0015-0.15mmol L-1。在本实施例中,为了获得具有较高光吸收效率和光催化降解有机物能力的锰掺杂二氧化钛纳米纤维材料,需要控制二氧化钛的生成速率以及锰离子(主要为Mn4+和Mn3 +)掺杂速率,二氧化钛前驱体和含锰化合物(高锰酸钾溶液和硝酸锰溶液)的浓度必须控制在上述比例范围之内,本领域技术人员可以理解的是,在上述浓度范围内二氧化钛前驱体、高锰酸钾和硝酸锰所配制的溶液均可满足后续制备符合需求的锰掺杂二氧化钛纳米纤维材料的需要,因此可根据需要在上述范围内进行调节,例如,二氧化钛前驱体的浓度为1、2、4、6、8、10mmol L-1等,或者符合上述条件的任一值均可。与之相似,高锰酸钾和硝酸锰的浓度分别为满足0.001-0.1mmol L-1、0.0015-0.15mmol L-1的任一值。在本实施例中,两亲性短肽主要是为制备锰掺杂二氧化钛纳米纤维材料提供模板,除了提供模板导向作用之外,还为二氧化钛的水解缩聚反应提供催化作用。因此,两亲性短肽的浓度既与其是否能形成稳定的一维组装体有关,同时也影响二氧化钛的反应速率。可以理解的是,在上述浓度范围内的两亲性短肽,能够满足制备锰掺杂二氧化钛纳米纤维材料的要求,本领域技术人员可以根据需要进行选择。In an embodiment of the present invention, the concentration of the amphiphilic short peptide is 0.5-10 mmol L -1 , the concentration of the titanium dioxide precursor is 1-10 mmol L -1 , and the concentration of potassium permanganate is 0.001-0.1 mmol L -1 -1 , the concentration of manganese nitrate is 0.0015-0.15 mmol L -1 . In this embodiment, in order to obtain a manganese-doped titania nanofiber material with higher light absorption efficiency and photocatalytic ability to degrade organic matter, it is necessary to control the generation rate of titania and the doping rate of manganese ions (mainly Mn 4+ and Mn 3 + ) , the concentration of titanium dioxide precursor and manganese-containing compound (potassium permanganate solution and manganese nitrate solution) must be controlled within the above-mentioned ratio range, those skilled in the art can understand that within the above-mentioned concentration range, titanium dioxide precursor, high manganese The solution prepared by potassium acid and manganese nitrate can meet the needs of subsequent preparation of manganese-doped titanium dioxide nanofiber materials that meet the needs, so it can be adjusted within the above range as needed. For example, the concentration of the titanium dioxide precursor is 1, 2, 4, 6, 8, 10 mmol L -1 , etc., or any value that meets the above conditions is acceptable. Similarly, the concentrations of potassium permanganate and manganese nitrate are any values satisfying 0.001-0.1 mmol L -1 and 0.0015-0.15 mmol L -1 , respectively. In this embodiment, the amphiphilic short peptide mainly provides a template for the preparation of manganese-doped titania nanofiber materials. In addition to providing template guidance, it also provides catalysis for the hydrolysis and polycondensation reaction of titania. Therefore, the concentration of amphiphilic short peptides is not only related to their ability to form stable one-dimensional assemblies, but also affects the reaction rate of titanium dioxide. It can be understood that the amphiphilic short peptide within the above concentration range can meet the requirements for preparing manganese-doped titania nanofiber materials, and those skilled in the art can choose according to needs.

在本发明的一实施例中,将两亲性阳离子短肽分散于水中后,将pH值调节到5-9的范围内。在本实施例中,将pH值调节到5-9的范围内,可确保反应体系整体在近中性的环境下反应,以保证整个合成过程具有环境友好的特点。可以理解的是,可将pH值调节6、7、8不等或上述范围内的其它任一点值均可。In an embodiment of the present invention, after dispersing the amphiphilic cationic short peptide in water, the pH value is adjusted to a range of 5-9. In the present embodiment, adjusting the pH value within the range of 5-9 can ensure that the entire reaction system reacts in a near-neutral environment, so as to ensure that the entire synthesis process is environmentally friendly. It can be understood that the pH value can be adjusted to 6, 7, 8, or any other value within the above range.

在本步骤中,对灰褐色沉淀依次采用纯水和乙醇进行洗涤,目的是为了除去未反应的二氧化钛前驱体、高锰酸钾、硝酸锰等化合物。In this step, the gray-brown precipitate is washed with pure water and ethanol in turn, in order to remove unreacted titanium dioxide precursor, potassium permanganate, manganese nitrate and other compounds.

在本发明的一实施例中,所述离心处理的转速为5000-10000rpm,时间为20-60分钟。在本实施例中,为了分离得到锰掺杂二氧化钛纳米纤维材料,采用离心处理的方式将其分离。可以理解的是,离心处理的转速和时间限定在上述范围内时,可使纳米材料的分离效果较好,本领域技术人员可根据实际情况在上述范围内进行调节。具体的,离心处理的转速可以为4000、5000、6000、7000、8000、9000、10000rpm,时间可以为20、30、40、50、60分钟等,除此之外,只要是离心处理的转速和时间处于上述范围内的任意值均可。In an embodiment of the present invention, the rotational speed of the centrifugal treatment is 5000-10000 rpm, and the time is 20-60 minutes. In this embodiment, in order to separate and obtain the manganese-doped titanium dioxide nanofiber material, centrifugation is used to separate it. It can be understood that when the rotational speed and time of the centrifugal treatment are limited within the above ranges, the separation effect of nanomaterials can be better, and those skilled in the art can adjust within the above ranges according to the actual situation. Specifically, the rotational speed of the centrifugal treatment can be 4000, 5000, 6000, 7000, 8000, 9000, 10000 rpm, and the time can be 20, 30, 40, 50, 60 minutes, etc. In addition, as long as the rotational speed of the centrifugal treatment and Any value within the above range may be used for the time.

本发明的另一实施例提供了一种如上述实施例中任一项所述的锰掺杂二氧化钛纳米纤维材料的制备方法所制备得到的锰掺杂二氧化钛纳米纤维材料。由本发明实施例制备得到的锰掺杂二氧化钛纳米纤维材料,锰元素主要以Mn3+和Mn4+离子的状态存在二氧化钛中,并取代部分Ti4+离子进入二氧化钛的晶格结构中,造成了晶格收缩。多价态的锰离子掺杂为二氧化钛提供了多个中间能级,拓宽了材料的光响应范围,掺杂后的二氧化钛其可见光吸收能力增强,而且掺杂能够有效的抑制光生电子-空穴的复合,从而使其对有机污染物表现出良好的光催化降解性质。另一方面,由本发明实施例制备得到的锰掺杂二氧化钛纳米纤维材料的直径在10-20纳米之间,具有较大的比表面积和表面结合位点,而且较小的电子迁移路径降低了光生电子和空穴复合的机率,进一步提升了材料的光催化降解效率。Another embodiment of the present invention provides a manganese-doped titanium dioxide nanofiber material prepared by the method for preparing a manganese-doped titanium dioxide nanofiber material according to any one of the above embodiments. In the manganese-doped titanium dioxide nanofiber material prepared by the embodiment of the present invention, the manganese element mainly exists in the titanium dioxide in the state of Mn 3+ and Mn 4+ ions, and replaces part of the Ti 4+ ions into the lattice structure of titanium dioxide, resulting in Lattice shrinkage. Multivalent manganese ion doping provides multiple intermediate energy levels for TiO2, which broadens the photoresponse range of the material. The doped TiO2 has enhanced visible light absorption capability, and doping can effectively inhibit photogenerated electron-hole. composite, so that it exhibits good photocatalytic degradation properties for organic pollutants. On the other hand, the diameter of the manganese-doped titania nanofiber material prepared by the embodiment of the present invention is between 10 and 20 nanometers, has a large specific surface area and surface binding sites, and a small electron migration path reduces the photogenerated The probability of electron and hole recombination further improves the photocatalytic degradation efficiency of the material.

由本发明实施例制备得到的锰掺杂二氧化钛纳米纤维材料具有较高的比表面积、良好的可见光响应性质和光电传输行为,因此具有良好的光催化性质。当作为光催化剂用于有机污染物的降解时,具有比商业化纳米二氧化钛更加优异的光催化活性,且具有良好的重复使用性,因此适合用作环境中有机污染物的光催化试剂。The manganese-doped titanium dioxide nanofiber material prepared by the embodiment of the present invention has high specific surface area, good visible light response properties and photoelectric transmission behavior, and thus has good photocatalytic properties. When used as a photocatalyst for the degradation of organic pollutants, it has more excellent photocatalytic activity than commercial nano-titania, and has good reusability, so it is suitable for use as a photocatalytic reagent for organic pollutants in the environment.

为了更清楚详细地介绍本发明实施例所提供的锰掺杂二氧化钛纳米纤维材料的制备方法,以下将结合具体实施例进行说明。In order to introduce the preparation method of the manganese-doped titania nanofiber material provided by the embodiments of the present invention more clearly and in detail, the following will be described with reference to specific embodiments.

实施例1Example 1

锰掺杂二氧化钛纳米纤维材料的制备Preparation of Manganese-Doped Titanium Dioxide Nanofibrous Materials

(1)两亲性阳离子短肽自组装溶液的配制(1) Preparation of amphiphilic cationic short peptide self-assembly solution

将一定质量的两亲性阳离子短肽分散在水中,超声分散,调节溶液pH值至5-9,置于室温放置7-14天,得到两亲性阳离子短肽自组装体溶液;Dispersing a certain mass of amphiphilic cationic short peptides in water, ultrasonically dispersing, adjusting the pH of the solution to 5-9, and placing at room temperature for 7-14 days to obtain an amphiphilic cationic short peptide self-assembly solution;

(2)锰掺杂二氧化钛纳米纤维材料的合成(2) Synthesis of manganese-doped titania nanofibers

A)将二氧化钛前驱体、高锰酸钾溶液和硝酸锰溶液依次加入到所述两亲性短肽自组装溶液中,溶液中两亲性阳离子短肽、二氧化钛前驱体、高锰酸钾、硝酸锰的浓度分别为0.5-10mmol L-1、1-10mmol L-1、0.001-0.1mmol L-1、0.0015-0.15mmol L-1,涡旋混匀,在室温反应10-24小时后,离心(5000-10000rpm,20-60分钟)得到灰褐色沉淀;A) Adding titanium dioxide precursor, potassium permanganate solution and manganese nitrate solution to the self-assembly solution of amphiphilic short peptides in sequence, in the solution, the amphiphilic cationic short peptide, titanium dioxide precursor, potassium permanganate, nitric acid The concentrations of manganese were 0.5-10 mmol L -1 , 1-10 mmol L -1 , 0.001-0.1 mmol L -1 , 0.0015-0.15 mmol L -1 , mixed by vortex, reacted at room temperature for 10-24 hours, and then centrifuged. (5000-10000rpm, 20-60 minutes) to obtain gray-brown precipitate;

B)将所得灰褐色沉淀交替采用纯水和乙醇洗涤,然后在300-500℃加热2-10小时,得到锰掺杂二氧化钛纳米纤维材料。B) The obtained gray-brown precipitate is washed alternately with pure water and ethanol, and then heated at 300-500° C. for 2-10 hours to obtain a manganese-doped titanium dioxide nanofiber material.

实施例2Example 2

锰掺杂二氧化钛纳米纤维材料的形貌和结构表征Morphology and structural characterization of manganese-doped titania nanofibers

采用高分辨透射电子显微镜,型号:JEM-2100UHR,仪器生产厂家:日本电子(JEOL),加速电压:200kV。High-resolution transmission electron microscope, model: JEM-2100UHR, instrument manufacturer: JEOL, accelerating voltage: 200kV.

本实施例结合高分辨透射电子显微镜观察锰掺杂二氧化钛纳米纤维材料的形貌和结构,具体的,将样品分散在乙醇中,滴在镀有碳膜的铜网上,干燥后利用专用的样品杆放入样品室,抽真空,调节合适的分辨率和焦距,选择合适的曝光时间,拍摄图像。In this example, the morphology and structure of the manganese-doped titanium dioxide nanofiber material were observed with high-resolution transmission electron microscopy. Specifically, the sample was dispersed in ethanol, dropped on a copper mesh coated with carbon film, and dried using a special sample rod. Put it into the sample chamber, evacuate it, adjust the appropriate resolution and focal length, choose the appropriate exposure time, and take an image.

结果发现,所得样品具有一维纳米结构,其直径为10-20纳米,长度为几百纳米甚至几个微米,如图1所示。在纳米纤维之外,无规则沉积较少,说明两亲性阳离子短肽模板对无机矿物及其前驱体具有较好的模板导向作用,二氧化钛的水解缩聚、高锰酸钾和硝酸锰的氧化还原反应在有机模板的控制下进行。It was found that the obtained sample had a one-dimensional nanostructure with a diameter of 10-20 nanometers and a length of several hundred nanometers or even several micrometers, as shown in Figure 1. Outside the nanofibers, there are less random depositions, indicating that the amphiphilic cationic short peptide template has a good template-directing effect on inorganic minerals and their precursors. The reaction is carried out under the control of an organic template.

实施例3Example 3

锰掺杂二氧化钛纳米纤维材料的光响应性质表征Characterization of light-responsive properties of manganese-doped titania nanofibers

采用紫外可见分光光度仪(附带漫反射测定装置-积分球,岛津公司生产,UV-1700PharmaSpec),扫描速度为中速,狭缝宽为1nm,测量范围200-800nm,以超细硫酸钡做参比,将样品涂于硫酸钡片上压片后进行测量。Using a UV-Vis spectrophotometer (with a diffuse reflectance measuring device-integrating sphere, produced by Shimadzu Corporation, UV-1700PharmaSpec), the scanning speed is medium speed, the slit width is 1nm, and the measurement range is 200-800nm. For reference, the sample was coated on a barium sulfate sheet and pressed for measurement.

如图2所示,单纯的二氧化钛的光吸收全部在紫外区域,在大于400nm的可见光区基本没有吸收,而通过锰掺杂改性后,材料在可见光区的响应明显增强,根据Kubelak-Munk公式计算其禁带宽度可达1.55eV,可通过掺杂含量和掺杂方式的变化进行调节。As shown in Figure 2, the light absorption of pure titanium dioxide is all in the ultraviolet region, and there is basically no absorption in the visible light region greater than 400 nm. After modification by manganese doping, the response of the material in the visible light region is significantly enhanced. According to the Kubelak-Munk formula It is calculated that the forbidden band width can reach 1.55 eV, which can be adjusted by changing the doping content and doping method.

实施例4Example 4

锰掺杂二氧化钛纳米纤维材料的组成、化学状态分析Composition and chemical state analysis of manganese-doped titania nanofibers

采用ThermoFisher SCIENTIFIC公司的ESCALAB 250型X射线电子能谱仪,选用Al靶,Kα射线。将粉末样品均匀铺在铝箔上,盖上一片铝箔,用液压机压平,揭开,将压成片状的样品用导电胶带粘于样品托上,放入仪器样品室内抽真空10h后进行检测。其原理是用X射线去辐射样品,使原子或分子的内层电子或价电子受激发发射出来,被光子激发出来的电子成为光电子,可以测量光电子的能量,以光电子的动能为横坐标,相对强度为纵坐标可作出光电子能谱图,从而获得待测物质组成。ESCALAB 250 X-ray electron energy spectrometer of ThermoFisher SCIENTIFIC Company was used, Al target and Kα rays were selected. Spread the powder sample evenly on the aluminum foil, cover it with a piece of aluminum foil, flatten it with a hydraulic press, open it up, stick the pressed sheet-like sample on the sample holder with conductive tape, put it into the sample chamber of the instrument and vacuumize it for 10 hours before testing. The principle is to use X-rays to irradiate the sample, so that the inner electrons or valence electrons of atoms or molecules are excited and emitted, and the electrons excited by photons become photoelectrons, and the energy of photoelectrons can be measured. When the intensity is the ordinate, a photoelectron spectrum can be drawn to obtain the composition of the substance to be measured.

从图3A可以看到,纯二氧化钛样品中Ti 2p1/2和Ti 2p3/2的结合能峰位分别为459.2eV和464.9eV,自旋能量间隔为5.7eV,对应于TiO2的Ti4+离子,与标准二氧化钛自旋能量间隔十分吻合。当掺杂锰以后,Ti 2p特征峰结合能峰位向着低结合能方向发生迁移,但自旋能量间隔并未发生变化,说明二氧化钛中的Ti元素仍以Ti4+存在。为了解体系中锰元素的价态,对Mn 2p特征峰谱图进行反褶积分峰处理分析。图3B为锰掺杂二氧化钛样品的Mn2p特征峰反褶积谱图,通过分峰可以看到Mn 2p3/2峰可以分出两个峰,峰位置分别落在641.9eV和643.1eV,这两个峰分别对应Mn3+和Mn4+的Mn 2p3/2峰,通过Mn3+/Mn4+的比值可以计算不同价态锰离子的相对含量。Mn4+离子的结合能与二氧化锰相比提高了0.7eV,这是由锰离子与主相中存在的Ti4+和O2-发生化学相互作用造成的。以上结果表明,在锰掺杂二氧化钛纳米纤维材料体系中,锰元素以Mn3+离子和Mn4+离子两种形式存在,代替部分Ti4+进入二氧化钛晶格中,表明体系中具有多个掺杂能级,这将更加有利于拓宽二氧化钛的光响应范围。It can be seen from Fig. 3A that the binding energy peak positions of Ti 2p 1/2 and Ti 2p 3/2 in the pure TiO sample are 459.2 eV and 464.9 eV, respectively, and the spin energy interval is 5.7 eV, corresponding to the Ti 4 of TiO 2 + ions, which are in good agreement with the standard titania spin energy interval. When doped with manganese, the binding energy peak position of Ti 2p characteristic peak shifts to the direction of lower binding energy, but the spin energy interval does not change, indicating that the Ti element in TiO2 still exists as Ti 4+ . In order to understand the valence state of manganese in the system, the Mn 2p characteristic peak spectrum was analyzed by deconvolution integration. Figure 3B shows the deconvolution spectrum of the Mn2p characteristic peak of the manganese-doped titanium dioxide sample. It can be seen that the Mn 2p 3/2 peak can be divided into two peaks through the peak separation, and the peak positions fall at 641.9eV and 643.1eV, respectively. The peaks correspond to the Mn 2p 3/2 peaks of Mn 3+ and Mn 4+ respectively. The relative content of manganese ions in different valence states can be calculated by the ratio of Mn 3+ /Mn 4+ . The binding energy of Mn 4+ ions is increased by 0.7 eV compared with manganese dioxide, which is caused by the chemical interaction of manganese ions with Ti 4+ and O 2- present in the main phase. The above results show that in the manganese-doped titanium dioxide nanofiber material system, manganese exists in the form of Mn 3+ ions and Mn 4+ ions, which replace part of Ti 4+ into the titanium dioxide lattice, indicating that the system has multiple doped ions. Heterogeneous energy level, which will be more beneficial to broaden the photoresponse range of TiO2.

实施例5Example 5

锰掺杂二氧化钛纳米纤维材料的光电响应性质表征Characterization of Photoelectric Response Properties of Manganese-Doped Titanium Dioxide Nanofibers

利用电化学工作站(上海辰华仪器有限公司,CHI660D)进行测试。采用三电极体系,以制备的样品作为工作电极,工作面积为1cm2。对电极为铂片电极,参比电极选用饱和干汞电极(SCE),电解液为1Mol L-1的Na2SO4溶液。利用300W氙灯作为光源,使用时加滤光片,波长范围>420nm。工作电极制备过程为:取0.2g样品与0.06g聚乙二醇(PEG,分子量为4000)混合,加入1mL乙醇充分搅拌研磨制成浆料。用透明胶在导电玻璃(ITO)上粘出1cm×1cm的空白区域,将制得的浆料涂覆在该区域,待涂层室温下干燥,将制得的电极置于马弗炉中400℃下煅烧30min。The test was performed using an electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd., CHI660D). A three-electrode system was adopted, the prepared sample was used as the working electrode, and the working area was 1 cm 2 . The counter electrode is a platinum sheet electrode, the reference electrode is a saturated dry mercury electrode (SCE), and the electrolyte is a 1 Mol L -1 Na 2 SO 4 solution. Use a 300W xenon lamp as a light source, add a filter when using, and the wavelength range is >420nm. The preparation process of the working electrode is as follows: take 0.2 g of the sample and mix it with 0.06 g of polyethylene glycol (PEG, molecular weight 4000), add 1 mL of ethanol and fully stir and grind to make a slurry. A blank area of 1 cm × 1 cm was glued on the conductive glass (ITO) with transparent glue, the prepared slurry was coated on this area, and the coating was dried at room temperature, and the prepared electrode was placed in a muffle furnace for 400 calcined at ℃ for 30 min.

首先在避光条件下使用开路电位-时间模式测试样品的开路电位,由于样品的形貌,成分等条件差异,导致表面电荷分布不同,开路电位的测试时间不固定,实验中当开路电位在30s内变化小于0.0001V时,认为体系达到稳定状态,记录此时的开路电位数值。对工作电极施加开路电位大小的电压,防止样品本身电位对光电流的干扰,确保开灯后的电流全部由光照导致生成,记录电流随时间变化。测试时先稳定100s后打开光源,以30s作为一个时间间隔,依次开灯关灯,如此循环5次,记录电流随开关光源变化的曲线。First, the open circuit potential of the sample is tested in the open circuit potential-time mode under dark conditions. Due to the difference in the morphology and composition of the sample, the surface charge distribution is different, and the test time of the open circuit potential is not fixed. In the experiment, when the open circuit potential is 30s When the internal change is less than 0.0001V, the system is considered to reach a stable state, and the open circuit potential value at this time is recorded. The voltage of the open circuit potential is applied to the working electrode to prevent the interference of the potential of the sample itself to the photocurrent, to ensure that the current after the lamp is turned on is all generated by the illumination, and the current changes with time are recorded. During the test, the light source was first stabilized for 100s and then turned on. With 30s as a time interval, the lights were turned on and off in turn. This cycle was repeated 5 times, and the curve of the current changing with the switch light source was recorded.

通过图4可以看到,开灯瞬间检测到较强的电流信号,说明样品受到激发产生了大量光电子,随着光照时间的增加,光电流呈现出下降趋势,但幅度不大。这是由于光照期间,光生电子和空穴处于持续的快速复合中,且复合速率要略快于样品受到光照激发产生新的光生电子的速率,从而在宏观上表现为光电流下降状态。复合速率越快,电流变化曲线越陡,达到平衡的时间越短。开灯30s后关灯避光,由于光生电子与空穴快速复合,且不再有新的光生电子产生,光电流几乎瞬间降为零。避光30s后再次开灯光照,样品受光激发产生大量光电子,光电流瞬间激增。通过对比发现,纯二氧化钛样品在开灯期间光电流强度最低,而掺杂锰离子后光电流强度迅速增加,可以达到未掺杂样品的4倍以上。这是由于金属离子的掺杂能够作为电子(或空穴)的浅势捕陷阱,从而降低光生电子-空穴的复合效率。As can be seen from Figure 4, a strong current signal was detected at the moment of turning on the light, indicating that the sample was excited to generate a large number of photoelectrons. With the increase of illumination time, the photocurrent showed a downward trend, but the amplitude was not large. This is because the photo-generated electrons and holes are in continuous rapid recombination during the illumination period, and the recombination rate is slightly faster than the rate at which the sample is excited by the illumination to generate new photo-generated electrons, thus showing a state of decreasing photocurrent on a macroscopic scale. The faster the recombination rate, the steeper the current curve and the shorter the time to reach equilibrium. After turning on the light for 30s, turn off the light and avoid light. Since the photo-generated electrons and holes are rapidly recombined, and no new photo-generated electrons are generated, the photocurrent drops to zero almost instantaneously. After being protected from light for 30s, the light was turned on again, and the sample was excited by light to generate a large number of photoelectrons, and the photocurrent surged instantly. By comparison, it is found that the photocurrent intensity of the pure titanium dioxide sample is the lowest during the turn-on period, while the photocurrent intensity increases rapidly after doping with manganese ions, which can reach more than 4 times that of the undoped sample. This is because the doping of metal ions can act as a shallow trap for electrons (or holes), thereby reducing the recombination efficiency of photogenerated electrons and holes.

实施例6Example 6

锰掺杂二氧化钛纳米纤维材料的光催化降解有机污染物性质表征Characterization of photocatalytic degradation of organic pollutants by manganese-doped titania nanofibers

采用紫外可见分光光度仪(岛津公司生产,UV-1700PharmaSpec),狭缝宽1nm,扫描范围200-800nm。将样品置于氙灯下,采用波长大于420nm的可见光照射,取不同照射时间的样品进行测试。A UV-Vis spectrophotometer (produced by Shimadzu Corporation, UV-1700PharmaSpec) was used, the slit width was 1 nm, and the scanning range was 200-800 nm. The samples were placed under a xenon lamp and irradiated with visible light with a wavelength greater than 420 nm, and samples with different irradiation times were taken for testing.

图5A为锰掺杂二氧化钛样品以及商业化二氧化钛(P25)在可见光下(>420nm)的亚甲基蓝(MB)催化降解实验。MB在663nm处达到最大吸光度,染料的吸光度随着光照时间减小说明了染料被分解。在未加入催化剂的空白实验中,MB吸光度在可见光照射下出现非常轻微的降低,说明其水溶液在可见光下比较稳定,自分解速率缓慢,不会对实验结果造成影响。与商业化的纳米二氧化钛(P25)相比,锰离子掺杂的二氧化钛具有更好的光催化效率。图5B为锰掺杂二氧化钛样品以及商业化二氧化钛(P25)在可见光下(>420nm)的罗丹明B(RhB)催化降解实验,与降解MB类似,锰掺杂二氧化钛纳米纤维材料表现出了更优异的光催化降解效果。Figure 5A shows the methylene blue (MB) catalytic degradation experiments of manganese-doped titania samples and commercial titania (P25) under visible light (>420 nm). MB reached the maximum absorbance at 663 nm, and the absorbance of the dye decreased with the illumination time, indicating that the dye was decomposed. In the blank experiment with no catalyst added, the absorbance of MB showed a very slight decrease under visible light irradiation, indicating that its aqueous solution is relatively stable under visible light, and the self-decomposition rate is slow, which will not affect the experimental results. Compared with commercialized nano-TiO2 (P25), manganese ion-doped TiO2 has better photocatalytic efficiency. Figure 5B shows the catalytic degradation experiments of rhodamine B (RhB) under visible light (>420 nm) for manganese-doped titanium dioxide samples and commercial titanium dioxide (P25). Similar to the degradation of MB, manganese-doped titanium dioxide nanofibers showed better performance photocatalytic degradation effect.

光催化剂的循环稳定性是除了光催化活性以外另一个非常重要的评价标准。以商业化纳米二氧化钛(P25)作为参照,考察了锰掺杂二氧化钛纳米纤维材料的循环使用稳定性,如图6A所示。经过5次循环,锰掺杂二氧化钛纳米纤维材料的光催化效率没有明显的降低,亚甲基蓝的降解率仍能保持在93%以上。而P25经过5次循环实验后,亚甲基蓝的降解率由76%减少到59%,如图6B所示,说明锰掺杂二氧化钛纳米纤维材料相比P25具有更好的循环稳定性。两种材料在循环稳定性上所表现出来的明显差别,其主要原因是材料形貌结构的不同。二氧化钛光催化降解有机物主要发生在材料表面,P25的形貌为纳米颗粒,在光催化过程中容易发生纳米颗粒的聚集从而导致比表面积下降;而利用两亲性阳离子短肽合成的锰掺杂二氧化钛纳米纤维材料具有一维结构,不仅能够有效缩短电子的迁移路径,提高光生载流子的传输效率,增强材料自身的光催化活性,同时还能够避免循环过程中发生的聚集现象,进一步提高材料的循环稳定性。The cycling stability of photocatalysts is another very important evaluation criterion besides photocatalytic activity. Taking commercial nano-titania (P25) as a reference, the cycling stability of the manganese-doped titania nanofiber material was investigated, as shown in Figure 6A. After 5 cycles, the photocatalytic efficiency of the manganese-doped titania nanofiber material did not decrease significantly, and the degradation rate of methylene blue remained above 93%. After 5 cycles of P25, the degradation rate of methylene blue was reduced from 76% to 59%, as shown in Figure 6B, indicating that the manganese-doped titania nanofiber material has better cycling stability than P25. The obvious difference in the cycle stability of the two materials is mainly due to the difference in the morphology and structure of the materials. The photocatalytic degradation of organic compounds in titanium dioxide mainly occurs on the surface of the material. The morphology of P25 is nanoparticles, and the aggregation of nanoparticles is easy to occur during the photocatalysis process, which leads to the decrease of the specific surface area. The nanofiber material has a one-dimensional structure, which can not only effectively shorten the migration path of electrons, improve the transmission efficiency of photogenerated carriers, and enhance the photocatalytic activity of the material itself, but also can avoid the aggregation phenomenon during the cycle process, and further improve the material's performance. Cyclic stability.

Claims (5)

1. A preparation method of a manganese-doped titanium dioxide nanofiber material is characterized by comprising the following steps:
ultrasonically dispersing amphiphilic cationic short peptide molecules into water, adjusting the pH value of the solution to be within the range of 5-9, and placing at room temperature for more than 1 week to obtain a self-assembly solution of the amphiphilic short peptide;
sequentially adding a titanium dioxide precursor, a potassium permanganate solution and a manganese nitrate solution into the amphiphilic short peptide self-assembly solution, uniformly mixing by vortex, reacting at room temperature for 10-24 hours, centrifuging to obtain a grey brown precipitate, washing the precipitate, heating at the temperature of 300 ℃ and 500 ℃ for 2-10 hours to remove a short peptide template to obtain a manganese-doped titanium dioxide nanofiber material;
the hydrophobic unit of the amphiphilic cationic short peptide consists of 3-6 leucine, isoleucine, glycine and valine, the hydrophilic head group consists of 1-2 lysine, histidine and arginine, and a nanofiber structure can be formed in an aqueous solution;
the titanium dioxide precursor is selected from at least one of n-butyl titanate, isopropyl titanate and bis (2-hydroxypropionic acid) diammonium dihydroxide titanium;
the concentration of the amphiphilic short peptide is 0.5-10 mmol.L-1The concentration of the titanium dioxide precursor is 1-10 mmol.L-1, the concentration of potassium permanganate is 0.001-0.1 mmol.L-1The concentration of manganese nitrate is 0.0015-0.15 mmol.L-1
2. The method according to claim 1, wherein the washing treatment comprises washing the grayish brown precipitate with pure water and ethanol alternately.
3. The method as claimed in claim 1, wherein the rotation speed of the centrifugation treatment is 5000-10000rpm for 20-60 minutes.
4. A manganese-doped titanium dioxide nanofiber material prepared by the method for preparing a manganese-doped titanium dioxide nanofiber material as claimed in any one of claims 1 to 3.
5. Use of the manganese-doped titanium dioxide nanofiber material of claim 4 in photocatalytic degradation of organic pollutants.
CN201710767439.0A 2017-08-31 2017-08-31 A kind of preparation method of manganese-doped titanium dioxide nanofiber material Active CN107413387B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201710767439.0A CN107413387B (en) 2017-08-31 2017-08-31 A kind of preparation method of manganese-doped titanium dioxide nanofiber material

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201710767439.0A CN107413387B (en) 2017-08-31 2017-08-31 A kind of preparation method of manganese-doped titanium dioxide nanofiber material

Publications (2)

Publication Number Publication Date
CN107413387A CN107413387A (en) 2017-12-01
CN107413387B true CN107413387B (en) 2020-02-18

Family

ID=60435567

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201710767439.0A Active CN107413387B (en) 2017-08-31 2017-08-31 A kind of preparation method of manganese-doped titanium dioxide nanofiber material

Country Status (1)

Country Link
CN (1) CN107413387B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110327926B (en) * 2019-06-18 2023-07-14 中国石油大学(华东) A kind of preparation method of iron ion doped titanium dioxide nanometer material

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007052861A1 (en) * 2005-11-02 2007-05-10 Korea Institute Of Science And Technology Metal oxide supercapacitor having metal oxide electrode coated onto the titanium dioxide ultrafine and its fabrication method
CN101535536A (en) * 2006-09-06 2009-09-16 康宁股份有限公司 Nanofibers, nanofilms and methods of making/using thereof
CN104910256A (en) * 2015-07-10 2015-09-16 重庆医科大学 Self-assembly short peptides and application thereof to gold electrode modification
CN105709687A (en) * 2016-01-21 2016-06-29 广西大学 Nano titanium dioxide composite material applicable to wastewater treatment
CN106668941A (en) * 2017-02-17 2017-05-17 中国石油大学(华东) Preparation method of short-peptide/silicon dioxide/hydroxyapatite porous composite material

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007052861A1 (en) * 2005-11-02 2007-05-10 Korea Institute Of Science And Technology Metal oxide supercapacitor having metal oxide electrode coated onto the titanium dioxide ultrafine and its fabrication method
CN101535536A (en) * 2006-09-06 2009-09-16 康宁股份有限公司 Nanofibers, nanofilms and methods of making/using thereof
CN104910256A (en) * 2015-07-10 2015-09-16 重庆医科大学 Self-assembly short peptides and application thereof to gold electrode modification
CN105709687A (en) * 2016-01-21 2016-06-29 广西大学 Nano titanium dioxide composite material applicable to wastewater treatment
CN106668941A (en) * 2017-02-17 2017-05-17 中国石油大学(华东) Preparation method of short-peptide/silicon dioxide/hydroxyapatite porous composite material

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
锰掺杂纳米二氧化钛的制备及其可见光催化性能;张霞 等;《化工进展》;20100630;第29卷(第6期);第1072页左栏第2段,第1.1节,第1074页右栏第3节 *
锰离子掺杂纳米二氧化钛及其应用性能;阳小宇 等;《化工技术与开发》;20110228;第40卷(第2期);第1页第1.1节,第3页第3节 *

Also Published As

Publication number Publication date
CN107413387A (en) 2017-12-01

Similar Documents

Publication Publication Date Title
US11345616B2 (en) Heterojunction composite material consisting of one-dimensional IN2O3 hollow nanotube and two-dimensional ZnFe2O4 nanosheet, and application thereof in water pollutant removal
Li et al. Z-scheme BiVO4/g-C3N4 heterojunction: an efficient, stable and heterogeneous catalyst with highly enhanced photocatalytic activity towards Malachite Green assisted by H2O2 under visible light
Li et al. CQDS preluded carbon-incorporated 3D burger-like hybrid ZnO enhanced visible-light-driven photocatalytic activity and mechanism implication
CN105032468B (en) A kind of Cu2O‑TiO2/g‑C3N4Ternary complex and its methods for making and using same
CN103480399B (en) Micronano-structured and silver phosphate based composite visible light catalytic material and preparing method thereof
Bai et al. Facet engineered interface design of NaYF 4: Yb, Tm upconversion nanocrystals on BiOCl nanoplates for enhanced near-infrared photocatalysis
Baraton Nano-TiO2 for solar cells and photocatalytic water splitting: scientific and technological challenges for commercialization
CN106475125B (en) Graphite phase carbon nitride and nano-titanium dioxide composite coating additive and preparation method
CN104826637B (en) Preparation method of BiOBr/Bi2O3 heterojunction composite catalyst
Huo et al. SnO 2 nanorod@ TiO 2 hybrid material for dye-sensitized solar cells
CN101850263A (en) A kind of Ag-doped BiOBr catalytic material and its preparation method and application
Zhu et al. One-step synthesis of flower-like WO 3/Bi 2 WO 6 heterojunction with enhanced visible light photocatalytic activity
Zhang et al. Controllable synthesis of Ag@ TiO 2 heterostructures with enhanced photocatalytic activities under UV and visible excitation
Guan et al. Controlled synthesis of Ag-coated TiO2 nanofibers and their enhanced effect in photocatalytic applications
Meng et al. Fabrication of nanocomposites composed of silver cyanamide and titania for improved photocatalytic hydrogen generation
CN109647377B (en) Electrochemical self-doping type WO3Particle-supported TiO2Nanotube and preparation method and application thereof
CN105056980A (en) A kind of Ag3PO4/TiO2 nanotube array composite photocatalyst and its preparation method
CN103143379A (en) Method for preparing nitrogen-doped titanium dioxide inverse opal thin-film photocatalyst by using one-step method
Heshmatpour et al. A probe into the effect of fixing the titanium dioxide by a conductive polymer and ceramic on the photocatalytic activity for degradation of organic pollutants
CN101966450A (en) High-efficiency composite photocatalyst and preparation method thereof
Wang et al. Synthesis of BiVO 4–TiO 2–BiVO 4 three-layer composite photocatalyst: effect of layered heterojunction structure on the enhancement of photocatalytic activity
Ma et al. All-inorganic TiO2/Cs2AgBiBr6 composite as highly efficient photocatalyst under visible light irradiation
Yang et al. Fabrication of carbon nanotube-loaded TiO 2@ AgI and its excellent performance in visible-light photocatalysis
CN108339544A (en) Photochemical catalyst/super-hydrophobic film composite material of fullerene carboxy derivatives modification
CN107413387B (en) A kind of preparation method of manganese-doped titanium dioxide nanofiber material

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant