CN102125863A

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Info

Publication number: CN102125863A
Application number: CN 201110028708
Authority: CN
Inventors: 张平; 罗和安; 赵才贤; 陈烽; 张永胜
Original assignee: Xiangtan University
Current assignee: Xiangtan University
Priority date: 2011-01-27
Filing date: 2011-01-27
Publication date: 2011-07-20

Abstract

本发明公开了一种石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的制备方法，其特征在于制备步骤如下：a)将氰胺类化合物或尿素溶于溶液中，再将制备好金红石单晶二氧化钛纳米线阵列浸入氰胺类化合物或尿素溶液中，然后取出并干燥；b)将干燥好的纳米线阵列进行热处理，即制得石墨相氮化碳/金红石单晶二氧化钛纳米线阵列。本发明具有以下优点：制备方法简单，成本低，适合大规模工业化生产；所制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列具有良好的可见光响应活性，可广泛应用于光催化、光解水制氢、光电转换等领域。

The invention discloses a preparation method of graphite phase carbon nitride/rutile single crystal titanium dioxide nanowire array, which is characterized in that the preparation steps are as follows: a) dissolving cyanamide compounds or urea in the solution, and then the prepared rutile single crystal The crystalline titanium dioxide nanowire array is immersed in a cyanamide compound or urea solution, then taken out and dried; b) heat-treating the dried nanowire array to obtain a graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array. The invention has the following advantages: the preparation method is simple, the cost is low, and it is suitable for large-scale industrial production; the prepared graphitic phase carbon nitride/rutile single crystal titanium dioxide nanowire array has good visible light response activity, and can be widely used in photocatalysis, photocatalysis, etc. Hydrogen production from water splitting, photoelectric conversion and other fields.

Description

Translated fromChinese

一种石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的制备方法A preparation method of graphite phase carbon nitride/rutile single crystal titanium dioxide nanowire array

技术领域technical field

本发明涉及一种二氧化钛纳米线阵列的制备方法，特别是涉及一种具有可见光响应活性的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的制备方法，属于光催化领域。The invention relates to a preparation method of a titanium dioxide nanowire array, in particular to a preparation method of a graphite phase carbon nitride/rutile single crystal titanium dioxide nanowire array with visible light response activity, and belongs to the field of photocatalysis.

背景技术Background technique

半导体光催化技术由于能将纯洁无污染而又取之不尽的太阳能的利用与环境保护相结合，受到各国研究者的普遍关注。一维有序的单晶二氧化钛纳米线阵列，可使光生电子沿一维纳米材料与基底进行直接输运，减少光生载流子(电子-空穴对)在晶界的复合，从而有效提高量子产率(CN101786597A；Grimes，Nano Letter，2008：3781；Eray S.Aydil，J.A.C.S，2009：3985)。但由于二氧化钛为宽带隙半导体体化合物(3.0～3.2eV)，仅能利用太阳光辐照的紫外线部分(约占太阳能的3％左右，而太阳光能量主要集中在400～800nm的可见光范围)，太阳能利用率较低。因此，研制具有可见光响应的高催化活性的二氧化钛纳米线阵列对于利用自然光降解环境污染物或光解水制氢具有重大意义。Semiconductor photocatalysis technology has attracted widespread attention of researchers from various countries because it can combine the use of pure, non-polluting and inexhaustible solar energy with environmental protection. The one-dimensional ordered single-crystal titanium dioxide nanowire array can make the photogenerated electrons transport directly along the one-dimensional nanomaterial and the substrate, reduce the recombination of photogenerated carriers (electron-hole pairs) at the grain boundary, and effectively improve the quantum efficiency. Yield (CN101786597A; Grimes, Nano Letter, 2008: 3781; Eray S. Aydil, J.A.C.S, 2009: 3985). However, since titanium dioxide is a wide-bandgap semiconductor compound (3.0-3.2eV), it can only use the ultraviolet part irradiated by sunlight (accounting for about 3% of solar energy, and the energy of sunlight is mainly concentrated in the visible light range of 400-800nm), The utilization rate of solar energy is low. Therefore, the development of highly catalytically active TiO nanowire arrays with visible light response is of great significance for the use of natural light to degrade environmental pollutants or photolyze water to produce hydrogen.

目前，有关二氧化钛光催化剂改性的文献及专利已有大量报道。其中，通过将二氧化钛与其他半导体材料复合是一种重要的改性方法。石墨相氮化碳(g-C₃N₄)是最近报道的一种新型无金属聚合物半导体光催化剂(Wong，Nature Mater.，2009，8：76-80)，它具有禁阻带宽较小(2.7eV)，光谱响应范围较宽，制备工艺简单，价格低廉等独特优势。通过将石墨相氮化碳与二氧化钛复合，能有效拓宽光谱响应范围，提高光催化效率。如专利CN10791565A通过水热及热解两步反应制备了核壳型TiO2@石墨相氮化碳复合光催化剂，复合光催化剂的吸收边带红移至约475nm，在可见光辐照下，60min即可降解约80％的4-氯苯酚。Horst Kisch(Photochem.Photoblol.SCi.，2008，7，40)通过将二氧化钛粉体与尿素混合热解，也制得了表面氮化碳改性的二氧化钛，其光谱响应范围可扩展至750nm。但目前有关氮化碳与二氧化钛复合光催化剂的报道仅局限于纳米粉体材料，其并不能减少光生载流子在晶界及催化剂颗粒间的复合。此外，在具体使用过程中，如用于降解废水中的有机污染物等，必需经过复杂的光催化剂分离步骤，同时也不利于采用连续工艺对污水进行处理。因此，探索一种制备成本低廉，使用方便的复合催化剂对于实际应用意义重大。At present, there have been a large number of reports on the literature and patents on the modification of titanium dioxide photocatalysts. Among them, compounding titanium dioxide with other semiconductor materials is an important modification method. Graphite carbon nitride (gC₃ N₄ ) is a new type of metal-free polymer semiconductor photocatalyst recently reported (Wong, Nature Mater., 2009, 8: 76-80), which has a small forbidden bandwidth (2.7 eV), wide spectral response range, simple preparation process, low price and other unique advantages. By combining graphite phase carbon nitride and titanium dioxide, the spectral response range can be effectively broadened and the photocatalytic efficiency can be improved. For example, the patent CN10791565A prepared a core-shell TiO2@graphite-phase carbon nitride composite photocatalyst through two-step reaction of hydrothermal and pyrolysis. The absorption sideband of the composite photocatalyst was red-shifted to about 475nm. Under visible light irradiation, it takes 60min. Degrade about 80% of 4-chlorophenol. Horst Kisch (Photochem.Photoblol.SCi., 2008, July, 40) also prepared titanium dioxide modified by carbon nitride on the surface by pyrolyzing titanium dioxide powder and urea, and its spectral response range can be extended to 750nm. However, the current reports on carbon nitride and titanium dioxide composite photocatalysts are limited to nanopowder materials, which cannot reduce the recombination of photogenerated carriers at grain boundaries and between catalyst particles. In addition, in the specific use process, such as degrading organic pollutants in wastewater, it is necessary to go through complicated photocatalyst separation steps, and it is also not conducive to the use of continuous processes to treat wastewater. Therefore, exploring a composite catalyst with low preparation cost and convenient use is of great significance for practical application.

发明内容Contents of the invention

本发明的目的是针对现有技术的不足，提供一种制备成本低廉，使用方便，同时具有良好可见光响应的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的制备方法。The object of the present invention is to address the deficiencies of the prior art and provide a method for preparing a graphitic phase carbon nitride/rutile single crystal titanium dioxide nanowire array with low preparation cost, convenient use and good visible light response.

本发明的目的是通过以下技术方案实现的：通过简单的浸渍法使氮化碳前驱物(氰胺化合物或尿素)渗进光金红石单晶二氧化钛纳米线阵列，然后升温热解，即可制得石墨相氮化碳/金红石单晶二氧化钛纳米线阵列。The purpose of the present invention is achieved through the following technical solutions: the carbon nitride precursor (cyanamide compound or urea) is infiltrated into the photorutile single crystal titanium dioxide nanowire array by a simple impregnation method, and then heated and pyrolyzed to obtain Graphite-phase carbon nitride/rutile single-crystal titania nanowire arrays.

本发明的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列具体制备步骤如下：The specific preparation steps of the graphite phase carbon nitride/rutile single crystal titanium dioxide nanowire array of the present invention are as follows:

a)在基底上制备金红石单晶二氧化钛纳米线阵列；a) preparing a rutile single crystal titania nanowire array on a substrate;

b)将氰胺类化合物或尿素溶于溶液中，再将制备好的金红石单晶二氧化钛纳米线阵列浸入氰胺类化合物或尿素溶液中1～48h后，取出并干燥。b) dissolving the cyanamide compound or urea in the solution, then immersing the prepared rutile single crystal titanium dioxide nanowire array in the cyanamide compound or urea solution for 1-48 hours, taking it out and drying it.

c)将干燥好的纳米线阵列进行热处理。c) heat-treating the dried nanowire array.

所述氰胺类化合物是指氰胺、双聚氰胺或三聚氰胺之一种或几种之混合物；所述溶液的溶剂可为蒸馏水或乙醇之任一种；所述金红石单晶二氧化钛纳米线阵列的基底可为导电玻璃、硅片、钛片、玻璃、石英或陶瓷之任一种；所述干燥温度为30～120℃；所述热处理温度为300℃～600℃，热处理时间为0.5～3h，热处理气氛为空气气氛或情性气氛；所述情性气氛是指氮气或氩气。The cyanamide compound refers to one or more mixtures of cyanamide, dicyandiamide or melamine; the solvent of the solution can be any of distilled water or ethanol; the rutile single crystal titanium dioxide nanowire array The substrate can be any one of conductive glass, silicon wafer, titanium wafer, glass, quartz or ceramics; the drying temperature is 30-120°C; the heat treatment temperature is 300°C-600°C, and the heat treatment time is 0.5-3h , the heat treatment atmosphere is an air atmosphere or an inert atmosphere; the inert atmosphere refers to nitrogen or argon.

本发明制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的光活性测试通过将其组装成光电化学(PEC)电池光解水制氢进行考察。测试过程为：将石墨相氮化碳/金红石单晶二氧化钛纳米线阵列焊接导线后，采用环氧树脂密封作为工作电极，铂网作为对电极，饱合甘汞电极作为参比电极，1M NaOH作为电解质，300W氙灯(PerkinElmer)作为模拟太阳光源，利用CHI 760D电化学工作站测试光解水制氢性能。从测试结果(图7)可知：在施加相同电压的条件下，采用石墨相氮化碳/金红石单晶二氧化钛纳米线阵列作为工作电极的PEC电池的光电流密度较未改性的要大得多，表明光解水制氢的光电转化效率提高。The photoactivity test of the graphitic phase carbon nitride/rutile single crystal titanium dioxide nanowire array prepared by the present invention is investigated by assembling it into a photoelectrochemical (PEC) cell for photolysis of water to produce hydrogen. The test process is as follows: After the graphite phase carbon nitride/rutile single crystal titanium dioxide nanowire array is welded to the wire, it is sealed with epoxy resin as the working electrode, the platinum mesh is used as the counter electrode, the saturated calomel electrode is used as the reference electrode, and 1M NaOH is used as the reference electrode. Electrolyte, 300W xenon lamp (PerkinElmer) as a simulated solar light source, using CHI 760D electrochemical workstation to test the performance of photolysis of water for hydrogen production. From the test results (Figure 7), it can be seen that under the same voltage conditions, the photocurrent density of the PEC cell using graphite phase carbon nitride/rutile single crystal titanium dioxide nanowire array as the working electrode is much higher than that of the unmodified one. , indicating that the photoelectric conversion efficiency of photolysis of water to hydrogen is improved.

本发明制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的可见光催化活性测试通过可见光照下亚甲基蓝的脱色进行表征。可见光催化活性测试过程为：将2cm²阵列膜(其余部分用环氧树脂密封)浸入50ml 1.25×10^-5M的亚甲基蓝溶液，避光下搅拌60min后，更换新鲜的亚甲基蓝溶液，然后开启300W氙灯(PerkinElmer)(带420nm滤光片，光强约40mJ/cm²)，定时取样并用分光光度计(PerkinElmer Lambda 25)测试残余亚甲基蓝溶液在660nm的吸收值。测试结果(图8)说明本发明制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列具有良好可见光催化活性。The visible light catalytic activity test of the graphite phase carbon nitride/rutile single crystal titanium dioxide nanowire array prepared by the present invention is characterized by the decolorization of methylene blue under visible light. The test process of visible light catalytic activity is as follows: immerse a 2cm² array film (the rest is sealed with epoxy resin) into 50ml of 1.25×10^-5 M methylene blue solution, stir for 60min in the dark, replace with fresh methylene blue solution, and then turn on the 300W xenon lamp (PerkinElmer) (with a 420nm filter, the light intensity is about 40mJ/cm² ), take samples regularly and use a spectrophotometer (PerkinElmer Lambda 25) to test the absorption value of the residual methylene blue solution at 660nm. The test result ( FIG. 8 ) shows that the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared by the present invention has good visible light catalytic activity.

本发明具有如下的有益效果：(1)制备工艺简单，所采用的原料均为已工业化规模生产的化工原料且价格低廉，因此采用本发明的方法制备而成的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列成本低。浸渍法实施非常方便，适合大规模工业化生产。同时，本发明采用水或低成本的乙醇作为溶剂，既有效降低了生产成本，同时也不会对环境造成污染；(2)本发明所制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列使用非常方便，可采用连续工艺对污水进行处理，能有效降低污水处理成本；(3))本发明所制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列不仅量子产率高，同时也能提高太阳能利用率。由于单晶二氧化钛纳米线内部不存在晶界，光生载流子可沿纳米线与基底直接传输，减少了其在晶界的复合，从而提高了量子产率。此外，石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的光谱响应范围可扩展至整个可见光区(850nm)，有效提高了太阳能利用率。The present invention has the following beneficial effects: (1) the preparation process is simple, and the raw materials used are chemical raw materials produced on an industrial scale and are cheap, so the graphite phase carbon nitride/rutile single Crystalline titania nanowire arrays are low cost. The impregnation method is very convenient to implement and is suitable for large-scale industrial production. At the same time, the present invention uses water or low-cost ethanol as a solvent, which not only effectively reduces the production cost, but also does not pollute the environment; (2) the graphite phase carbon nitride/rutile single crystal titanium dioxide nanowires prepared by the present invention The array is very convenient to use, and the sewage can be treated by a continuous process, which can effectively reduce the cost of sewage treatment; (3)) The graphite phase carbon nitride/rutile single crystal titanium dioxide nanowire array prepared by the present invention not only has a high quantum yield, but also It can also improve the utilization rate of solar energy. Since there is no grain boundary inside the single crystal titanium dioxide nanowire, the photogenerated carriers can be directly transported along the nanowire and the substrate, reducing their recombination at the grain boundary, thereby improving the quantum yield. In addition, the spectral response range of graphitic carbon nitride/rutile single-crystal titanium dioxide nanowire arrays can be extended to the entire visible light region (850nm), which effectively improves the utilization rate of solar energy.

附图说明Description of drawings

图1是本发明石墨相氮化碳/金红石单晶二氧化钛纳米线阵列制备过程示意图。Fig. 1 is a schematic diagram of the preparation process of graphite phase carbon nitride/rutile single crystal titanium dioxide nanowire array of the present invention.

图2是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列与对比例的X射线衍射图。Fig. 2 is an X-ray diffraction diagram of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention and a comparative example.

图3是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的场发射扫描电子显微镜(FSEM)图。Fig. 3 is a field emission scanning electron microscope (FSEM) image of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention.

图4是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的透射电镜图。Fig. 4 is a transmission electron microscope image of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention.

图5是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的高分辨透射电镜图。Fig. 5 is a high-resolution transmission electron microscope image of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention.

图6是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列与对比例的紫外-可见漫反射吸收光谱图。Fig. 6 is an ultraviolet-visible diffuse reflectance absorption spectrum diagram of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention and a comparative example.

图7是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列与对比例组装成光电化学(PEC)池的线性扫描伏安曲线。7 is a linear sweep voltammetry curve of a photoelectrochemical (PEC) cell assembled into a graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention and a comparative example.

图8是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列在可见光辐照下降解亚甲基蓝的性能。Fig. 8 shows the performance of methylene blue degradation of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention under visible light irradiation.

具体实施方式Detailed ways

以下通过具体的实施例对发明的技术方案作进一步描述。The technical solution of the invention will be further described below through specific examples.

金红石单晶二氧化钛纳米线阵列的制备可参考以下方法，但并非必需按照以下方法进行制备。金红石单晶二氧化钛纳米线阵列的制备方法的变动不构成对本发明的限定。The preparation of the rutile single crystal titania nanowire array can refer to the following method, but it is not necessary to follow the following method. The variation of the preparation method of the rutile single crystal titanium dioxide nanowire array does not constitute a limitation of the present invention.

金红石单晶二氧化钛纳米线阵列的制备：剧烈搅拌下，将12ml的四氯化钛加入400ml冰水，冰水浴冷却，搅拌30min后，撤去冰水浴，室温继续搅拌2h，制得四氯化钛水解液。室温下，将清洗干净的基底(导电玻璃、硅片、钛片、玻璃、石英或陶瓷等)浸入四氯化钛水解液24h，取出用无水乙醇洗涤三次，烘干，然后550℃加热30min，即得浸涂TiO₂晶种的基底。Preparation of rutile single-crystal titanium dioxide nanowire arrays: under vigorous stirring, add 12ml of titanium tetrachloride to 400ml of ice water, cool in an ice-water bath, stir for 30 minutes, remove the ice-water bath, and continue stirring at room temperature for 2 hours to obtain hydrolyzed titanium tetrachloride liquid. At room temperature, immerse the cleaned substrate (conductive glass, silicon wafer, titanium wafer, glass, quartz or ceramics, etc.) in titanium tetrachloride hydrolyzed solution for 24 hours, take it out, wash it with absolute ethanol three times, dry it, and then heat it at 550°C for 30 minutes , that is, a substrate for dip-coating TiO₂ seed crystals.

将35ml超纯水、35ml浓盐酸(36～38％)加入100ml烧杯，搅拌5min后，滴加1ml钛酸四正丁酯，继续搅拌10min，直至溶液澄清透明。将两片浸涂有TiO₂晶种的基底放入100ml四氟乙烯内衬水热反应釜，然后将钛酸四正丁酯的盐酸溶液加入，密封反应釜，180℃恒温6h冷却室温后，将基底取出，用超纯水清洗干净后，烘干。接着，将27ml超纯水、8ml氯化钠的饱和溶液、35ml浓盐酸(36～38％)加入100ml烧杯，搅拌5min后，滴加1ml钛酸四正丁酯，继续搅拌10min，直至溶液澄清透明。将上步制备有金红石单晶二氧化钛纳米线阵列的基底放入100ml四氟乙烯内衬水热反应釜，然后将钛酸四正丁酯的盐酸溶液加入，密封反应釜，150℃恒温20h，冷却室温后，将基底取出，用超纯水清洗干净后，烘干，即得金红石单晶二氧化钛纳米线阵列。Add 35ml of ultrapure water and 35ml of concentrated hydrochloric acid (36-38%) into a 100ml beaker, and after stirring for 5 minutes, add 1ml of tetra-n-butyl titanate dropwise, and continue stirring for 10 minutes until the solution is clear and transparent. Put two substrates dip-coated with TiO₂ seed crystals into a 100ml tetrafluoroethylene-lined hydrothermal reaction kettle, then add the hydrochloric acid solution of tetra-n-butyl titanate, seal the reaction kettle, keep the temperature at 180°C for 6h and cool it to room temperature, Take out the substrate, clean it with ultrapure water, and dry it. Next, add 27ml of ultrapure water, 8ml of saturated sodium chloride solution, and 35ml of concentrated hydrochloric acid (36-38%) into a 100ml beaker, and after stirring for 5 minutes, add 1ml of tetra-n-butyl titanate dropwise, and continue stirring for 10 minutes until the solution is clear transparent. Put the substrate prepared with rutile single crystal titanium dioxide nanowire arrays in the previous step into a 100ml tetrafluoroethylene-lined hydrothermal reaction kettle, then add the hydrochloric acid solution of tetra-n-butyl titanate, seal the reaction kettle, keep the temperature at 150°C for 20h, and cool After room temperature, the substrate is taken out, cleaned with ultrapure water, and dried to obtain a rutile single-crystal titanium dioxide nanowire array.

在本发明中，采用FTO导电玻璃作为基底制备的金红石单晶二氧化钛纳米线阵列作为对比例。In the present invention, a rutile single-crystal titanium dioxide nanowire array prepared by using FTO conductive glass as a substrate is used as a comparative example.

实施例1：Example 1:

将制备好的金红石单晶二氧化钛纳米线阵列(钛片作为基底)，浸入30g/L三聚氰胺的水溶液48h后，取出，120℃烘干。然后在氩气氛围下，300℃热解3h，即得石墨相氮化碳/金红石单晶二氧化钛纳米线阵列。The prepared rutile single crystal titanium dioxide nanowire array (titanium sheet as the substrate) was immersed in 30 g/L melamine aqueous solution for 48 hours, then taken out, and dried at 120° C. Then, under an argon atmosphere, pyrolyze at 300° C. for 3 hours to obtain a graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array.

实施例2：Example 2:

将制备好的金红石单晶二氧化钛纳米线阵列(陶瓷作为基底)，浸入50g/L的单氰胺水溶液24h后，取出，120℃烘干。然后在氮气氛围下，600℃热解1h，即得石墨相氮化碳/金红石单晶二氧化钛纳米线阵列。The prepared rutile single-crystal titanium dioxide nanowire array (ceramic as the substrate) was immersed in 50 g/L cyanamide aqueous solution for 24 hours, then taken out, and dried at 120° C. Then, under nitrogen atmosphere, pyrolyze at 600° C. for 1 hour to obtain graphite phase carbon nitride/rutile single crystal titanium dioxide nanowire array.

实施例3：Example 3:

将制备好的金红石单晶二氧化钛纳米线阵列(FTO导电玻璃作为基底)，浸入200g/L尿素的乙醇溶液12h后，取出，60℃烘干。然后在空气氛围下，400℃热解1h，即得石墨相氮化碳/金红石单晶二氧化钛纳米线阵列。The prepared rutile single crystal titanium dioxide nanowire array (FTO conductive glass as the substrate) was immersed in 200g/L urea ethanol solution for 12h, then taken out and dried at 60°C. Then, it was pyrolyzed at 400° C. for 1 h in an air atmosphere to obtain a graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array.

实施例4：Example 4:

将制备好的金红石单晶二氧化钛纳米线阵列(普通玻璃作为基底)，浸入300g/L尿素的乙醇溶液1h后，取出，30℃烘干。然后在空气氛围下，400℃热解1h，即得石墨相氮化碳/金红石单晶二氧化钛纳米线阵列。The prepared rutile single crystal titania nanowire array (common glass as the substrate) was immersed in 300 g/L urea ethanol solution for 1 hour, then taken out, and dried at 30°C. Then, it was pyrolyzed at 400° C. for 1 h in an air atmosphere to obtain a graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array.

实施例5：Example 5:

将制备好的金红石单晶二氧化钛纳米线阵列(石英片作为基底)，浸入100g/L尿素的乙醇溶液24h后，取出，60℃烘干。然后在空气氛围下，500℃热解1h，即得石墨相氮化碳/金红石单晶二氧化钛纳米线阵列。The prepared rutile single crystal titania nanowire array (quartz plate as a substrate) was immersed in 100 g/L urea ethanol solution for 24 hours, then taken out, and dried at 60° C. Then, it was pyrolyzed at 500° C. for 1 h in an air atmosphere to obtain a graphitic carbon nitride/rutile single-crystal titanium dioxide nanowire array.

图2是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列与对比例的X射线衍射图。从图可见，经石墨相氮化碳改性处理后，实施例制备的纳米线阵列的金红石002晶面的衍射峰(62.8°)增强，表明经高温热处理过程后，其结晶完善程度提高。Fig. 2 is an X-ray diffraction diagram of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention and a comparative example. It can be seen from the figure that after the graphite phase carbon nitride modification treatment, the diffraction peak (62.8°) of therutile 002 crystal plane of the nanowire array prepared in the embodiment is enhanced, indicating that after the high temperature heat treatment process, the degree of crystallization perfection is improved.

图3是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的场发射扫描电子显微镜(FSEM)图。从图可知：石墨相氮化碳/金红石单晶二氧化钛纳米线在FTO导电玻璃表面分布均匀，排列整齐有序。Fig. 3 is a field emission scanning electron microscope (FSEM) image of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention. It can be seen from the figure that the graphitic carbon nitride/rutile single crystal titanium dioxide nanowires are evenly distributed on the surface of the FTO conductive glass and arranged in an orderly manner.

图4是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的透射电镜图。从图可见：二氧化钛纳米线的直经约为5-10nm。Fig. 4 is a transmission electron microscope image of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention. It can be seen from the figure that the diameter of the titanium dioxide nanowire is about 5-10nm.

图5是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的高分辨透射电镜图。从图可知，在二氧化钛纳米线的周围包覆有许多氮化碳颗粒，其粒径约为2nm。Fig. 5 is a high-resolution transmission electron microscope image of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention. It can be seen from the figure that many carbon nitride particles are coated around the titanium dioxide nanowires, and the particle diameter is about 2nm.

图6是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列与对比例的紫外-可见漫反射吸收光谱图。表明石墨相氮化碳/金红石单晶二氧化钛纳米线阵列不仅在紫外区存在强烈吸收，同明在整个可见区也存在较强烈吸收。Fig. 6 is an ultraviolet-visible diffuse reflectance absorption spectrum diagram of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention and a comparative example. It shows that the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array not only has a strong absorption in the ultraviolet region, but also has a strong absorption in the entire visible region.

图7是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列与对比例组装成光电化学(PEC)池的线性扫描伏安曲线。从图可见，在无光照时，两者的电流几乎都为零。而在光照时，随着外加电压的增加，光电流密度迅速增加，但石墨相氮化碳/金红石单晶二氧化钛纳米线阵列光电化学(PEC)池的光电流密度较对比例的大得多。在外加电压为0V(相对于饱合甘汞电极)时，石墨相氮化碳/金红石单晶二氧化钛纳米线阵列的光电流密度为3.56mA/cm²，而在相同条件下对比例的仅为0.643mA/cm²，改性处理后性能提高了约4.5倍。7 is a linear sweep voltammetry curve of a photoelectrochemical (PEC) cell assembled into a graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention and a comparative example. It can be seen from the figure that when there is no light, the currents of both are almost zero. While under illumination, the photocurrent density increases rapidly with the increase of the applied voltage, but the photocurrent density of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array photoelectrochemical (PEC) cell is much larger than that of the comparative example. When the applied voltage is 0V (relative to the saturated calomel electrode), the photocurrent density of graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array is 3.56mA/cm² , while that of the comparative example under the same conditions is only 0.643mA/cm² , the performance is improved by about 4.5 times after modification.

图8是本发明实施例3制备的石墨相氮化碳/金红石单晶二氧化钛纳米线阵列在可见光辐照下降解亚甲基蓝的性能。从图可见，本发明制备的表面包覆碳层的金红石单晶二氧化钛核壳结构纳米线阵列具有良好的可见光响应活性，2cm²纳米线阵列在可见光(300W氙灯，PerkinElmer，带420nm滤光片，光强约40mJ/cm²)辐照下，120min即可使50ml 1.25×10^-5M的亚甲基蓝溶液分解约79％。Fig. 8 shows the performance of methylene blue degradation of the graphitic carbon nitride/rutile single crystal titanium dioxide nanowire array prepared in Example 3 of the present invention under visible light irradiation. As can be seen from the figure, the rutile single crystal titania core-shell structure nanowire array with a surface coated carbon layer prepared by the present invention has good visible light response activity, and the^2cm nanowire array is exposed to visible light (300W xenon lamp, PerkinElmer, with a 420nm filter, Under light intensity of about 40mJ/cm² ), 50ml of 1.25×10^-5 M methylene blue solution can be decomposed by about 79% within 120 minutes.

Claims

1. the preparation method of graphite phase carbon nitride/rutile single crystals titanium dioxide nanowire array is characterized in that preparation process is as follows:

A) preparation rutile single crystals titanium dioxide nanowire array in substrate;

B) cyanamide compounds or urea are dissolved in the solution, again the rutile single crystals titanium dioxide nanowire array for preparing are immersed in cyanamide compounds or the urea liquid behind 1～48h, take out and dry.

C) drying is good nano-wire array is heat-treated.

2. according to the preparation method of the described a kind of graphite phase carbon nitride of claim 1/rutile single crystals titanium dioxide nanowire array, it is characterized in that: described cyanamide compounds is meant one or more mixture of cyanamide, double focusing cyanamide or melamine; The solvent of described solution is distilled water or ethanol.

3. according to the preparation method of the described a kind of graphite phase carbon nitride of claim 1/rutile single crystals titanium dioxide nanowire array, it is characterized in that: the substrate of described rutile single crystals titanium dioxide nanowire array is electro-conductive glass, silicon chip, titanium sheet, glass, quartz or ceramic any.

4. according to the preparation method of the described a kind of graphite phase carbon nitride of claim 1/rutile single crystals titanium dioxide nanowire array, it is characterized in that: described baking temperature is 30～120 ℃.

5. according to the preparation method of the described a kind of graphite phase carbon nitride of claim 1/rutile single crystals titanium dioxide nanowire array, it is characterized in that: described heat treatment temperature is 300 ℃～600 ℃, heat treatment time is 0.5～3h, and heat-treating atmosphere is air atmosphere or natural instincts atmosphere.

6. according to the preparation method of the described a kind of graphite phase carbon nitride of claim 6/rutile single crystals titanium dioxide nanowire array, it is characterized in that: described natural instincts atmosphere is meant nitrogen or argon gas.