發(fā)布時(shí)間：2018-11-25 15:34

【摘要】：金屬氧化物半導(dǎo)體納米材料在紫外光照下能產(chǎn)生大量的電子和空穴對(duì),從而具有氧化還原性,可以應(yīng)用于光催化降解水中的有機(jī)污染物,而且材料的化學(xué)性質(zhì)穩(wěn)定、來(lái)源廣泛、成本低廉、環(huán)境友好,在光催化處理水污染方向有良好的應(yīng)用前景。但由于材料在制備時(shí)不易形成穩(wěn)定的結(jié)構(gòu),一般粒徑較大,產(chǎn)物可利用的比表面小,而且半導(dǎo)體材料的禁帶寬度較寬,只能被日光中不到5%的紫外光激發(fā),半導(dǎo)體材料的光生電子和空穴極易復(fù)合,對(duì)有機(jī)染料的降解率不高,限制了材料在光催化方面的應(yīng)用。本文旨在設(shè)計(jì)不同形貌結(jié)構(gòu)的納米金屬氧化物,通過(guò)構(gòu)筑一些獨(dú)特的結(jié)構(gòu)來(lái)提高對(duì)有機(jī)染料的吸附能力,從而提高材料對(duì)有機(jī)染料的光催化降解效率。論文主要制備了兩種特殊形貌的納米金屬氧化物:具有納米通孔的空心CuO微球和混相C/TiO_2納米球及其復(fù)合物。1)通過(guò)SiO_2模板輔助在水熱條件下合成制備一種具有開(kāi)放納米孔洞的空心CuO微球。以硅酸鈉作為堿性介質(zhì)相當(dāng)于SiO_2前驅(qū)體,CuSO_4和葡萄糖分別作為銅源和還原劑。上述合成產(chǎn)物在600℃高溫煅燒后,由Cu_2O/Si O_2混合物完全轉(zhuǎn)變?yōu)镃uO/SiO_2,最后經(jīng)由NaOH刻蝕法除去SiO_2,產(chǎn)物干燥后即得到具有開(kāi)放納米孔洞的空心CuO微球。對(duì)產(chǎn)物進(jìn)行表征發(fā)現(xiàn)CuO微球由大量微小CuO晶體顆粒組成,產(chǎn)物的空心內(nèi)層結(jié)構(gòu)和開(kāi)放納米孔洞結(jié)構(gòu)來(lái)源于SiO_2模板的去除。文章同時(shí)研究了硅酸鈉的含量對(duì)于產(chǎn)物結(jié)構(gòu)的影響,結(jié)果表明只有當(dāng)硅酸鈉達(dá)到一定含量時(shí)才能形成CuO微球。此外,還提出了這種納米結(jié)構(gòu)可能的形成機(jī)理,并探究了CuO微球在紫外光下對(duì)甲基橙(MO)的光催化降解,結(jié)果表明材料在75 min內(nèi)能完全降解MO,相同條件下CuO微球表現(xiàn)出遠(yuǎn)優(yōu)秀于商業(yè)CuO(~200 nm)的光催化活性,并且催化劑穩(wěn)定性高。2)制備了混晶(銳鈦礦相和金紅石相)和純銳鈦礦相TiO_2納米球(200 nm~400 nm)和金屬氧化物負(fù)載TiO_2復(fù)合材料。以PVP,葡萄糖為形貌結(jié)構(gòu)調(diào)節(jié)劑與鈦前驅(qū)體水熱作用,得到尺寸均一的混晶和純銳鈦礦C/TiO_2球形顆粒。通過(guò)研究發(fā)現(xiàn):反應(yīng)物種類、鈦源、還原劑的含量、Ti~(4+)的濃度等因素對(duì)制備TiO_2納米球的物相和形貌有著顯著的影響。另外,詳細(xì)研究了這些微球在可見(jiàn)光條件下對(duì)有機(jī)染料例如亞甲基藍(lán)(MB)、甲基橙(MO)、羅丹明(RhB)的光催化降解性能。結(jié)果顯示它們對(duì)MB染料的降解效果最好。探究了TiO_2及其復(fù)合材料在可見(jiàn)光下對(duì)一些染料(亞甲基藍(lán)(MB)、甲基橙(MO)、羅丹明B(RhB))的光催化性能,發(fā)現(xiàn)材料對(duì)MB染料的降解效果最好。其中TiO_2納米球和CuO/TiO_2都可以在30 min內(nèi)完全降解MB染料,60 min內(nèi)降解RhB染料達(dá)95%以上,相比商業(yè)P25表現(xiàn)出更好的催化效果。通過(guò)4次循環(huán)降解實(shí)驗(yàn),材料仍具有超過(guò)70%的降解效率,這表明銳鈦礦TiO_2及其復(fù)合材料具有穩(wěn)定的可見(jiàn)光催化性能。
[Abstract]:Metal oxide semiconductor nanomaterials can produce a large number of electron and hole pairs under ultraviolet light, so they can be redox and can be used in photocatalytic degradation of organic pollutants in water. Moreover, the materials have stable chemical properties and a wide range of sources. It is low cost and environment friendly. It has good application prospect in photocatalytic treatment of water pollution. However, it is not easy to form a stable structure when the material is prepared, the particle size is larger, the specific surface of the product is small, and the band gap of semiconductor material is wider, which can only be excited by less than 5% ultraviolet light in sunlight. The photogenerated electrons and holes of semiconductor materials are easy to be recombined, and the degradation rate of organic dyes is not high, which limits the application of semiconductor materials in photocatalysis. The purpose of this paper is to design nanometallic oxides with different morphologies, and to improve the adsorption ability of organic dyes by constructing some unique structures, so as to improve the photocatalytic degradation efficiency of organic dyes. Two kinds of nanometallic oxides with special morphology were prepared in this paper: hollow CuO microspheres with nanorods and miscible C/TiO_2 nanospheres and their complexes. 1) Synthesis under hydrothermal conditions assisted by SiO_2 template A hollow CuO microsphere with open nano hole was prepared. Sodium silicate as basic medium is equivalent to SiO_2 precursor, CuSO_4 and glucose are used as copper source and reducing agent, respectively. After calcined at 600 鈩，

本文編號(hào)：2356616