本文選題：石墨烯 + 氧化物��； 參考：《中北大學(xué)》2017年碩士論文

【摘要】：光催化是一種新型綠色環(huán)保技術(shù),由于其反應(yīng)條件溫和、無二次污染、操作設(shè)備簡單等優(yōu)點(diǎn)被廣泛地應(yīng)用于能源、環(huán)境等領(lǐng)域。光催化還原二氧化碳(CO_2)能夠產(chǎn)生有機(jī)燃料,能夠在一定的程度上解決能源與環(huán)境問題。但是目前單一催化劑具有比表面積小、光生電子-空穴對復(fù)合速率快、量子效率低等不足。使用石墨烯與半導(dǎo)體進(jìn)行復(fù)合,制備石墨烯基半導(dǎo)體納米材料能夠有效提升半導(dǎo)體的比表面積、抑制電子-空穴對的復(fù)合、活化CO_2,從而提升復(fù)合材料光催化還原CO_2的效率。TiO_2、CuO和NiO皆為常見的半導(dǎo)體氧化物,具有價格低廉、制備簡單等優(yōu)點(diǎn)。本文先使用改良Hummers法制備了氧化石墨(GO),然后使用水熱(溶劑熱)法將其與TiO_2、CuO和NiO進(jìn)行復(fù)合�？刂艷O的加入量來制備了一系列不同配比的氧化物-石墨烯復(fù)合物,并在模擬可見光下考察了其催化還原CO_2的活性。具體的工作內(nèi)容如下:1、使用溶劑熱法制備了不同還原氧化石墨烯(r-GO)配比的Ag-TiO_2/r-GO復(fù)合納米材料。使用X射線粉末衍射(XRD)、透射電子顯微鏡(TEM)、高分辨透射電子顯微鏡(HR-TEM)、紅外傅立葉變換光譜(FT-IR)、紫外-可見漫反射光譜(UV-VisDRS)、N2吸附-脫附測試以及光致發(fā)光光譜(PL)對制備的樣品進(jìn)行表征。結(jié)果表明通過Hummers法成功地制備了GO,Ag-TiO_2納米顆粒粒徑均一且均勻地分散在石墨烯的表面。r-GO的復(fù)合有效的拓寬了TiO_2的光吸收范圍、有效地抑制了電子-空穴對的復(fù)合。光催化結(jié)果表明,復(fù)合r-GO后TiO_2的光催化還原的CO_2活性明顯增強(qiáng)。r-GO的配比及催化劑的濃度對光催化的性能具有很大的影響。當(dāng)r-GO配比為15%,催化劑濃度為1.5g·L-1時,催化劑的活性最高,4h內(nèi)可以產(chǎn)生40μmol·gcat-1甲醇。循環(huán)實驗表明催化劑具有較強(qiáng)的光穩(wěn)定性。2、使用直接沉淀法制備CuO納米顆粒并用APTES進(jìn)行氨基改性。使用水熱法制備了不同r-GO配比CuO-r-GO復(fù)合納米材料。利用XRD、TEM、FT-IR、UV-VisDRS和PL對制備的樣品進(jìn)行表征。結(jié)果表明CuO均勻地附著在了r-GO的表面,r-GO的加入有效地抑制了光生電子-空穴的復(fù)合。光催化結(jié)果表明單一的CuO由于其較低的氧化-還原電勢,并不具有還原CO_2的能力。復(fù)合r-GO后復(fù)合,復(fù)合材料的光催化還原CO_2的能力明顯提高。3、使用水熱-煅燒法制備了碳球,以碳球為模板制備了中空NiO納米球。使用水熱法制備了不同r-GO配比的中空NiO-r-GO復(fù)合納米材料。使用XRD、TEM、FT-IR、UV-VisDRS和PL對制備的樣品進(jìn)行表征。結(jié)果表明制備的NiO納米球粒徑較為均一且在石墨烯上均勻地復(fù)合。單一NiO由于其較寬的帶隙寬度使其在可見光下催化還原CO_2的能力較弱。復(fù)合r-GO后,復(fù)合材料的光催化性能具有明顯的增強(qiáng)。
[Abstract]:Photocatalysis is a new green environmental protection technology, which has been widely used in energy, environment and other fields because of its mild reaction conditions, no secondary pollution, simple operation equipment and so on. Photocatalytic reduction of carbon dioxide (CO-2) can produce organic fuel and solve energy and environment problems to a certain extent. However, the single catalyst has some disadvantages, such as small specific surface area, fast photoelectron hole pair recombination rate and low quantum efficiency. The preparation of graphene based semiconductor nanomaterials can effectively enhance the specific surface area of semiconductors and inhibit the recombination of electron-hole pairs. Activation of CO2, thus enhancing the efficiency of photocatalytic reduction of CO2 in composites. Both TiO2CuO and nio are common semiconductor oxides, which have the advantages of low price and simple preparation. Graphite oxide (go) was prepared by modified Hummers method, and then it was compounded with TiO2CuO and nio by hydrothermal (solvothermal) method. A series of oxide-graphene complexes with different ratios were prepared by controlling the amount of go, and the catalytic reduction activity of COS _ 2 was investigated under simulated visible light. The specific work is as follows: 1. Ag-TiO2 / r-GO nanocomposites with different ratio of reduced graphene oxide (r-GO) were prepared by solvothermal method. The samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), infrared Fourier transform spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (UV-Vis DRS) N _ 2 adsorption-desorption and photoluminescence (PL) spectra. The results show that the composite of go-Ag-TiO-2 nanoparticles with uniform particle size and uniformly dispersed on the surface of graphene by Hummers method can effectively widen the range of optical absorption of TIO _ 2 and effectively inhibit the combination of electron-hole pairs. The photocatalytic results show that the photocatalytic activity of TiO-2 in tio _ 2 is obviously enhanced. The ratio of r -GO and the concentration of the catalyst have a great influence on the photocatalytic performance. When the molar ratio of r-GO is 15 and the concentration of the catalyst is 1.5 g L-1, the maximum activity of the catalyst can produce 40 渭 mol gcat-1 methanol within 4 h. Cyclic experiments showed that the catalyst had strong photostability. CuO nanoparticles were prepared by direct precipitation method and modified with APTES. CuO-r-GO nanocomposites with different r-GO ratios were prepared by hydrothermal method. The samples were characterized by UV-VisDRS and PL. The results show that the addition of CuO to the surface of r-GO effectively inhibits the photo-electron-hole recombination. The photocatalytic results show that a single CuO has no ability to reduce CO2 due to its low redox potential. After composite r-GO, the photocatalytic reduction ability of CO2 was improved significantly. The carbon spheres were prepared by hydrothermal calcination method, and hollow nio nanospheres were prepared using carbon spheres as template. Hollow NiO-r-GO composite nanomaterials with different r-GO ratios were prepared by hydrothermal method. UV-VisDRS and PL were used to characterize the prepared samples. The results showed that the nio nanospheres were homogeneous in size and homogeneously compounded on graphene. Because of its wide bandgap width, the single nio has a weak catalytic reduction of CO2 in visible light. The photocatalytic performance of the composite is obviously enhanced after the composite of r-GO.
【學(xué)位授予單位】：中北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O643.36

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