本文關(guān)鍵詞：煅燒溫度對摻雜二氧化鈦納米粉末可見光響應(yīng)的影響　出處：《華中科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： TiO2 溫度 摻雜 可見光

【摘要】：隨著工業(yè)化不斷深入發(fā)展,城市環(huán)境污染日益嚴(yán)重,而TiO2光催化降解有機(jī)污染物技術(shù)為解決該問題提供了有效方案。純TiO2量子產(chǎn)率低且?guī)短珜挓o法產(chǎn)生可見光響應(yīng),研究表明氮摻雜TiO2可將吸收波長從紫外光區(qū)拓展到可見光區(qū),但是不同方法制備的TiO2其可見光性能具有很大差異,其響應(yīng)機(jī)理也存在一定爭議,因此具有可見光響應(yīng)的二氧化鈦仍然停留在試驗(yàn)階段。本文為了進(jìn)一步促進(jìn)TiO2的商業(yè)化應(yīng)用,對TiO2的摻雜工藝進(jìn)行了深入的研究,通過調(diào)控煅燒溫度來實(shí)現(xiàn)高效可見光響應(yīng)TiO2的工藝開發(fā)。在氮摻雜工藝的基礎(chǔ)上,本文對比研究了煅燒溫度對氮?dú)涔矒诫s改性樣品的影響,以探索出更優(yōu)異的制備工藝。在具體的研究過程中,考察了煅燒溫度對氮摻雜以及氮?dú)涔矒诫s樣品的晶型結(jié)構(gòu)、表面形貌、光學(xué)性能以及可見光下光催化性能的影響,主要成果如下:1.隨著煅燒溫度的提高氮摻雜樣品其摻雜濃度迅速升高,其摻雜位置也從間隙位逐漸過渡到取代位,可見光響應(yīng)能力逐漸增強(qiáng)。氮摻雜濃度的升高可能會(huì)促進(jìn)樣品表面或者內(nèi)部大量氧空位等缺陷的產(chǎn)生,作為光生載流子的復(fù)合中心降低了光生電子空穴的分離效率,反而會(huì)抑制其可見光下光催化活性。2.相比單一氮摻雜工藝,氮?dú)涔矒诫s樣品在煅燒溫度提升中能保持更穩(wěn)定的氮摻雜濃度以及相穩(wěn)定性,并在樣品表面形成一層非晶層。隨著煅燒溫度的提高,其可見光響應(yīng)能力提升相對更緩慢,但是光生電子空穴的分離效率相比氮摻雜樣品更高,從而使低溫?fù)诫s樣品具有更好的光催化性能。3.當(dāng)煅燒溫度過高時(shí)會(huì)伴隨TiN的生成,雖然會(huì)大幅提升TiO2的可見光響應(yīng)能力,但作為非輻射復(fù)合的中心促進(jìn)大量光生電子空穴的復(fù)合,對可見光降解苯的性能極其有害。因此,無論是單一氮摻雜還是氮?dú)涔矒诫s其煅燒工藝都需要控制在600℃以下,從而保證樣品具有很好的可見光催化性能。
[Abstract]:With the deepening development of industrialization, urban environmental pollution is becoming more and more serious. TiO2 photocatalytic degradation of organic pollutants provides an effective solution to this problem. The pure TiO2 quantum yield is low and the band gap is too wide to produce visible light response. The results show that the absorption wavelength of nitrogen-doped TiO2 can be extended from the ultraviolet region to the visible region, but the visible light properties of TiO2 prepared by different methods are very different, and its response mechanism is also controversial. Therefore, titanium dioxide with visible light response is still in the experimental stage. In order to further promote the commercial application of TiO2, the doping process of TiO2 is deeply studied in this paper. On the basis of nitrogen doping process, the effect of calcination temperature on nitrogen-hydrogen co-doped modified samples was studied. In order to explore a better preparation process. In the specific research process, the crystal structure and surface morphology of N-doped and nitrogen-co-doped samples were investigated. The main results are as follows: 1. With the increase of calcination temperature, the doping concentration of nitrogen-doped samples increases rapidly. The doping position also gradually transition from gap site to substitution site, and the visible light response ability is gradually enhanced. The increase of nitrogen doping concentration may promote the generation of defects such as a large number of oxygen vacancies on or inside the surface of the sample. As the composite center of photogenerated carriers, the separation efficiency of photogenerated electron holes is reduced, but the photocatalytic activity of photocatalytic activity under visible light is inhibited. 2. Compared with the single nitrogen doping process. The nitrogen-hydrogen co-doped sample can maintain more stable nitrogen doping concentration and phase stability in the calcination temperature, and form a layer of amorphous layer on the surface of the sample, with the increase of calcination temperature. The enhancement of visible light response ability is slower, but the separation efficiency of photogenerated electron hole is higher than that of nitrogen doped sample. Thus, the low-temperature doped samples have better photocatalytic performance .3.When the calcination temperature is too high, the formation of TiN will be accompanied, although it will greatly improve the visible light response ability of TiO2. However, as the center of non-radiation recombination, it promotes the recombination of a large number of photogenerated electron holes, which is extremely harmful to the degradation of benzene by visible light. The calcination process of either single nitrogen doping or nitrogen hydrogen co-doping needs to be controlled below 600 鈩，

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