納米材料的表征方法

1、納米材料的表征及其催化效果評價方式納米材料的表征主要目的是確定納米材料的一些物理化學(xué)特性如形貌、尺寸、粒徑、等電點(diǎn)、化學(xué)組成、晶型結(jié)構(gòu)、禁帶寬度和吸光特性等。納米材料催化效果評價方式主要是在光照（紫外、可見光、紅外光或者太陽光）條件下納米材料對一些污染物質(zhì)（甲基橙、羅丹明B、亞甲基藍(lán)和Cr6+等）的降解或者對一些物質(zhì)的轉(zhuǎn)化（用于選擇性的合成過程）。評價指標(biāo)為污染物質(zhì)的去除效率、物質(zhì)的轉(zhuǎn)化效率以及反應(yīng)的一級動力學(xué)常數(shù)k的大小。1 、結(jié)構(gòu)表征 XRD，ED，F(xiàn)T-IR, Raman，DLS2 、成份分析AAS，ICP-AES，XPS，EDS3 、形貌表征TEM，SEM，AFM4 、性質(zhì)表征-光、電

2、、磁、熱、力等UV-Vis，PL，Photocurrent1. TEM TEM為透射電子顯微鏡，分辨率為0.10.2nm，放大倍數(shù)為幾萬百萬倍，用于觀察超微結(jié)構(gòu)，即小于0.2微米、光學(xué)顯微鏡下無法看清的結(jié)構(gòu)。TEM是一種對納米材料形貌、粒徑和尺寸進(jìn)行表征的常規(guī)儀器，一般納米材料的文獻(xiàn)中都會用到。The morphologies of the samples were studied by a Shimadzu SSX-550 field-emission scanning electron microscopy (SEM) system, and a JEOL JEM-2010 transmi

3、ssion electron microscopy (TEM)1. 一般情況下，TEM還會裝配High-Resolution TEM（高分辨率透射電子顯微鏡）、EDX（能量彌散X射線譜）和SAED（選區(qū)電子衍射）。High-Resolution TEM用于觀察納米材料的晶面參數(shù)，推斷出納米材料的晶型；EDX一般用于分析樣品里面含有的元素，以及元素所占的比率；SAED用于實現(xiàn)晶體樣品的形貌特征與晶體學(xué)性質(zhì)的原位分析。 2. SEM SEM表示掃描電子顯微鏡，可以獲取被測樣品本身的各種物理、化學(xué)性質(zhì)的信息，如形貌、組成、晶體結(jié)構(gòu)和電子結(jié)構(gòu)等等。SEM也是一種對納米材料形貌、粒徑和尺寸進(jìn)行表征的常規(guī)

4、儀器，一般納米材料的文獻(xiàn)中都會用到。The morphologies of the samples were studied by a Shimadzu SSX-550 field-emission scanning electron microscopy (SEM) system, and a JEOL JEM-2010 transmission electron microscopy (TEM)1. (a) SEM image of TiO2 nanofibers SEM一般會裝配EDX，用于分析材料的元素成分及所占比率。 3. AFM AFM是指原子力顯微鏡，原子力顯微鏡的優(yōu)點(diǎn)是在大氣條

5、件下，以高倍率觀察樣品表面，可用于幾乎所有樣品（對表面光潔度有一定要求），而不需要進(jìn)行其他制樣處理，就可以得到樣品表面的三維形貌圖象。The anatase (101) surface and the rutile (001), (100), and (110) surfaces have been characterized by X-ray diffraction (XRD) and by atomic force microscopy (AFM)2. 4. XRD XRD是X射線衍射的縮寫，通過對材料進(jìn)行X射線衍射，分析其衍射圖譜，獲得材料的成分、材料的晶型結(jié)構(gòu)、材料內(nèi)部原子或分子的結(jié)構(gòu)

6、或形態(tài)等信息的研究手段?；旧蠈τ诩{米材料的文獻(xiàn)都會用到。The phases of the samples were characterized by X-ray diffraction (XRD), employing a scanning rate of 0.05° per second in a 2 ranging from 10° to 80°, using a Bruker D8 Advance X-ray diffractometer (Cu K radiation, = 1.54178 Å)1. 5. DRS DRS是漫反射譜，是通過光在

7、檢驗物質(zhì)表面反射測其反射光線的光譜。主要用于測定納米材料的吸光特性，并據(jù)此估算出納米材料的禁帶寬度?？梢钥闯霾牧显诳梢姽庀率欠裼形眨话愫铣纱呋牧系奈墨I(xiàn)都會用到該儀器。The UVvis DRS was performed at room temperature on VARIAN Cary-5000 from 200 nm to 800 nm, using BaSO4 as the reflectance standard1.圖片來自3 6. PL PL是光致發(fā)光的縮寫，主要可以用來估計納米材料的電荷分離效率，實驗之前要先確定材料的激發(fā)波長。一般情況下，弱的熒光強(qiáng)度表示更高的電荷分離效率

8、，所以催化效果也會相應(yīng)的提高。The photoluminscence (PL) emission mainly resulted from the recombination of excited electrons and holes, and a lower PL intensity indicated a higher separation efficiency1.The photoluminescence (PL) spectra were recorded by F-4600 fluorescence spectrophotometer (Hitachi, Japan) under

9、 ambient conditions. The excitation wavelength was 315 nm, the scanning speed was 1200 nm/min, and the slot widths of the excitation slit and the emission slit were both 5.0 nm1. 7. XPS XPS是X射線光電子能譜分析的縮寫，XPS可以用來測量：元素的定性分析，可以根據(jù)能譜圖中出現(xiàn)的特征譜線的位置鑒定除H、He以外的所有元素；元素的定量分析，根據(jù)能譜圖中光電子譜線強(qiáng)度（光電子峰的面積）反應(yīng)原子的含量或相對濃度；固體

10、表面分析，包括表面的化學(xué)組成或元素組成，原子價態(tài)，表面能態(tài)分布，測定表面電子的電子云分布和能級結(jié)構(gòu)等；化合物的結(jié)構(gòu)，可以對內(nèi)層電子結(jié)合能的化學(xué)位移精確測量，提供化學(xué)鍵和電荷分布方面的信息。X-ray photoelectron spectroscopy (XPS) measurements were performed on a PHI 5000C ESCA system with Mg KR source operated at 14.0 kVand 25 mA. All the binding energies were referenced to the C1s peak at 284.

11、6 eV from the surface adventitious carbon4. 8. Raman通過對拉曼光譜的分析可以知道物質(zhì)的振動轉(zhuǎn)動能級情況，從而可以鑒別物質(zhì)，分析物質(zhì)的性質(zhì)。Raman spectroscopic measurements were performed on a Renishaw inVia Raman System 1000 with a 532 nm Nd:YAG excitation source at room temperature3. 9. FT-IR 紅外光譜，在有機(jī)物分子中，組成化學(xué)鍵或官能團(tuán)的原子處于不斷振動的狀態(tài)，其振動頻率與紅外光的振動頻率

12、相當(dāng)。所以，用紅外光照射有機(jī)物分子時，分子中的化學(xué)鍵或官能團(tuán)可發(fā)生震動吸收，不同的化學(xué)鍵或官能團(tuán)吸收頻率不同，在紅外光譜上將處于不同位置，從而可獲得分子中含有何種化學(xué)鍵或官能團(tuán)的信息。一般材料中含有機(jī)物的納米材料會用到FTIR分析（如石墨烯）。The Fourier transformed infrared spectroscopy (FTIR) was performed on a Nicolet Nexus 670 FTIR spectrophotometer at a resolution of 4 cm-13.Figure S1. The Fourier transformed inf

13、rared spectra (FTIR) of the ZnS-5%GR nanocomposite and the original GO. 10. DLS 動態(tài)光散射，DLS技術(shù)測量粒子粒徑，具有準(zhǔn)確、快速、可重復(fù)性好等優(yōu)點(diǎn)，已經(jīng)成為納米科技中比較常規(guī)的一種表征方法。隨著儀器的更新和數(shù)據(jù)處理技術(shù)的發(fā)展，現(xiàn)在的動態(tài)光散射儀器不僅具備測量粒徑的功能，還具有測量Zeta電位、大分子的分子量等的能力。Investigate the interaction of EPS with QDs at the two photic conditions (light and dark, described

14、above) by sizing microgels formation measured using dynamic light scattering (DLS; Brookhaven Instruments, Holtsville, NY USA)5. 11. BET測試法氮?dú)馕?解吸分析BET測試法是BET比表面積測試法的簡稱，主要可以看出納米材料的氮?dú)馕角€和孔徑分布圖。Specific surface areas of the catalysts were measured at 77 K by BrunauerEmmettTeller (BET) nitrogen adsorp

15、tiondesorption (Micromeritics ASAP 2010 Instrument)6.N2 Adsorption/Desorption Analysis. The N2 adsorption desorption isotherms and BarrettJoynerHalenda (BJH) pore size distributions of all the samples are shown in Figure 57.主要可以得出納米材料的吸附類型，之后可以得到材料的孔徑分布圖。 12. 光電流的測定 光生空穴和電子產(chǎn)生之后，空穴被電解液捕獲，而電子轉(zhuǎn)移到后接觸點(diǎn)，因

16、而產(chǎn)生光電流。因此對光電流的測定可以估計電荷的分離效率以及空穴電子對的復(fù)合效率，光電流的增強(qiáng)說明空穴電子對分離效率高并且存在更少的復(fù)合。The photocurrent developed by irradiating the photoanode (TiO2) with either UV or visible light was recorded with an electrochemical workstation (Model CHI660A, CH Instruments Co.). The photoelectrochemical cell was a three-electrod

17、e system: a TiO2 film located in the middle of the cell as a working electrode, a saturated calomel electrode as reference, and a platinum wire parallel to the working electrode as a counter electrode. All measurements were conducted at room temperature and ion a N2 atmosphere to obtain highly repro

18、ducible data. The electrolyte was 0.5 mol/L Na2SO4 aqueous solution. The working electrode was activated in the electrolyte for 2 h before measurement1. 13. ESR ESR是電子自旋共振的縮寫，電子順磁共振譜儀的主要應(yīng)用：一是研究礦物中順磁性雜質(zhì)離子(濃度低于1%)，如過度元素離子和稀土元素離子的類質(zhì)同像置換、有序-無序、化學(xué)鍵及晶格參量和局域?qū)ΨQ；二是研究于點(diǎn)缺陷有關(guān)的電子-空穴中心的類型、濃度、性質(zhì)等。The in situ elect

19、ron paramagnetic resonance (EPR) measurement was performed using an Endor spectrometer (JEOL ES-ED3X) at the liquid nitrogen temperature of 77 K. A microwave with the frequency of 9.42 GHz was used and its power was set at 1 mW8. 本文主要是為了看TiO2的氧空位的存在14. ICP-AES or AAS ICP-AES是指電感耦合等離子體原子發(fā)射光譜法，主要用來測定巖

20、石、礦物、金屬等樣品中數(shù)十種元素的含量。AAS是指原子吸收分光光度計，也可以用來測定樣品中的元素含量。所以這兩個儀器一般用于對于納米材料的摻雜量的估算。Elemental analysis for the Ag loading content of in the products were 1.1, 3.2, 5.1, and 8.3%, respectively by ICP-AES were as expected9.參考文獻(xiàn)1.Yang, Y. C., Wen, J. W., et al., Polypyrrole-Decorated Ag-TiO2 Nanofibers Exhibit

21、ing Enhanced Photocatalytic Activity under Visible-Light Illumination. ACS Applied Materials & Interfaces, 2013. 5(13): p.6201-6207.2.Ahmed, A. Y., Kandiel, T. A., et al., Photocatalytic Activities of Different Well-defined Single Crystal TiO2 Surfaces: Anatase versus Rutile. The Journal of Phys

22、ical Chemistry Letters, 2011. 2(19): p.2461-2465.3.Zhang, Y. H., Zhang, N., et al., Graphene Transforms Wide Band Gap ZnS to a Visible Light Photocatalyst. The New Role of Graphene as a Macromolecular Photosensitizer. ACS nano, 2012. 6(11): p.9777-9789.4.Yu, D. H., Yu, X. D., et al., Synthesis of Natural Cellulose-Templated TiO2/Ag Nanosponge Composites and Photocatalytic Properties. ACS Applied Materials & Interfaces, 2012. 4(5): p.2781-2787.5.Zhang, S. J., Jiang, Y. L., et al., Aggregation, Dissolution, and Stability of Quantum Dots in Marine Environments: Impo