本文選題：光催化　切入點：硼酸鹽　出處：《山東大學(xué)》2015年碩士論文

【摘要】：隨著人類社會步入現(xiàn)代文明,科學(xué)技術(shù)的進(jìn)步伴隨著越來越大的資源消耗和環(huán)境破壞；因此,如何解決上述兩大問題已逐步成為當(dāng)今社會關(guān)注的焦點。光催化技術(shù)是一種利用催化劑有效的將低密度的清潔太陽能轉(zhuǎn)換為高密度的化學(xué)能并進(jìn)一步應(yīng)用于污染物降解、光解水產(chǎn)氫和二氧化碳還原等領(lǐng)域的重要技術(shù)。由于半導(dǎo)體光催化劑是提高光催化反應(yīng)效率的最關(guān)鍵因素,因此在這方面的研究對于緩解人類面臨的能源危機和環(huán)境污染有著重要的意義及價值。經(jīng)過近半個世紀(jì)的研究探索,大量的具有光催化活性的半導(dǎo)體逐漸被報道；在堅實的理論及實驗基礎(chǔ)上科學(xué)家們發(fā)現(xiàn)光響應(yīng)范圍窄和量子效率低是制約光催化技術(shù)大規(guī)模工業(yè)化的重要限制因素。因此,解決上述兩個問題、使光催化技術(shù)盡快造福于社會是目前該領(lǐng)域極大部分研究工作包括本文的研究重點。探索新型光催化劑、半導(dǎo)體復(fù)合、金屬修飾及離子摻雜等手段是目前拓展光催化劑光響應(yīng)范圍或提高量子效率的有效辦法。但是,隨著科學(xué)的日益發(fā)展,上述各種方法逐步顯示出了一定的局限性。首先,目前在新型光催化劑的研究上雖然已經(jīng)取得了較大程度的成果和局部體系的突破,但該領(lǐng)域在總體研究無法形成統(tǒng)一的體系。其次,就構(gòu)建界面電場而言,其主要方法有半導(dǎo)體復(fù)合與金屬修飾；但界面電場存在電場強度小和界面缺陷多等諸多局限,因此作用范圍小和驅(qū)動力弱使該方法對光生載流子分離的促進(jìn)作用有限。最后,以引起晶格畸變?yōu)槟康牡碾x子摻雜由于摻雜種類、摻雜位置、摻雜量和摻雜方法等變量,導(dǎo)致了摻雜對光催化活性的促進(jìn)或抑制作用需要大量工作的摸索。因此,本文期望通過構(gòu)建整個晶體范圍內(nèi)的方向一致的內(nèi)部極化電場,以大范圍、強驅(qū)動力和少缺陷,達(dá)到促進(jìn)光生電子和空穴高效分離的目的,進(jìn)而從提高量子效率的角度解決材料光催化效率低的問題。本論文著重介紹了Bi2O2[BO2(OH)]和Bi2ZnOB2O6兩種極性光催化材料合成、改性及光催化原理,通過能帶分析及電子結(jié)構(gòu)分析給出了它們偶極矩的大小及方向并進(jìn)一步闡述了內(nèi)建電場促進(jìn)載流子分離的機制。主要研究內(nèi)容如下：第一章主要介紹了半導(dǎo)體光催化的基本原理、研究現(xiàn)狀及主要應(yīng)用。通過對光催化發(fā)展兩大制約因素的分析提出了硼酸鹽極性材料的內(nèi)部極化電場對提高材料量子效率的優(yōu)勢,進(jìn)而提出了本論文的選題意義及主要研究方向。第二章主要對Bi2O2[BO2(OH)]納米片的合成、生長機理和載流子分離機制進(jìn)行了研究。首先通過一步水熱法合成了Bi2O2[BO2(OH)],并通過對合成條件的調(diào)節(jié)最終得到了Bi2O2[BO2(OH)]納米片；進(jìn)一步通過對中間產(chǎn)物的研究明確了其生長機理。其后,通過對Bi2O2[BO2(OH)]的電子結(jié)構(gòu)分析得到了其偶極矩及能帶位置,并闡明了內(nèi)建電場促進(jìn)光生載流子分離的原理。最后通過樣品的光催化降解實驗結(jié)合理論證實了構(gòu)建內(nèi)建電場是一種高效促進(jìn)載流子分離并提升材料量子效率的方法。第三章主要對Bi2O2[BO2(OH)]納米片進(jìn)行了改性,以期解決極性材料帶隙展寬影響體系光吸收的問題。首先通過離子交換法合成了Bi2S3/Bi2O2[BO2(OH)]復(fù)合材料；通過XRD、SEM等表征手段得到了復(fù)合Bi2S3顆粒大小,并進(jìn)一步分析了具有量子尺寸效應(yīng)的Bi2S3與Bi2O2[BO2(OH)]的能帶關(guān)系；最終證實了該復(fù)合體系有效的拓展了光響應(yīng)范圍,提高了光催化活性。然后通過水熱過程加入微量貴金屬得到了M@ Bi2O2[BO2(OH)] (M=Ag、Au、Pt),通過XRD. SEM及UV-Vis漫反射等手段證實了體系中貴金屬的存在,同樣該改性方法也使體系的光響應(yīng)范圍得到了拓展,提高了光催化活性。第四章主要合成了Bi2ZnOB2O6微粒,并對其能帶結(jié)構(gòu)和載流子分離機制進(jìn)行了探索。首先通過固相燒結(jié)法合成了Bi2ZnOB2O6微粒,通過對合成條件的調(diào)節(jié)和XRD、SEM等測試結(jié)果的分析,確定了純相Bi2ZnOB2O6的合成方式；其次利用樣品比表面積和光催化降解速率的關(guān)系,得到了Bi2ZnOB2O6的本征光催化速率；最后通過結(jié)構(gòu)分析確定了Bi2ZnOB2O6的能帶位置和偶極矩,分析了內(nèi)建電場促進(jìn)載流子分離的機制,得到了其具有高本征光催化活性的根本原因。第五章對本論文工作進(jìn)行了總結(jié),整合了前幾章工作中得到的結(jié)論,分析了工作中的創(chuàng)新及不足,深入探討了未來工作的計劃及前景展望。
[Abstract]:With the human society entering the modern civilization , the progress of science and technology is accompanied by the increasing resource consumption and environmental damage ;
Therefore , how to solve the above two major problems has gradually become the focus of current social concern . The photocatalytic technology is an important technology in the fields of pollutant degradation , photodissociation , hydrogen production and carbon dioxide reduction . As the semiconductor photocatalyst is the most important factor to improve the efficiency of photocatalytic reaction , the research in this area is of great significance and value to alleviate the energy crisis and environmental pollution . After nearly half a century of research , a large number of semiconductors with photocatalytic activity have been reported ;
On the basis of solid theory and experiment , scientists have found that light response range is narrow and quantum efficiency is low is an important limiting factor that restricts the large - scale industrialization of photocatalysis technology .
This paper mainly introduces the synthesis , modification and photocatalytic principles of the photocatalytically active material . In chapter 1 , the author introduces the basic principle , the growth mechanism and the main research direction of the photocatalytically active material . The second chapter mainly introduces the synthesis , growth mechanism and the carrier separation mechanism of the photocatalytically active material .
The mechanism of its growth was further clarified by the study of intermediate products . After that , the dipole moment and energy band position were obtained by the electron structure analysis of the Bi _ 2SiO _ 2 ( OH ) 2 . Finally , the principle of promoting the separation of photogenerated carriers by the built - in electric field was demonstrated . Finally , the photocatalytic degradation experiment of the sample was carried out to confirm that the built - in electric field was a method to promote the separation of carriers and improve the quantum efficiency of the materials .
By means of XRD , SEM and other characterization methods , the particle size of composite bi2S3 particles was obtained , and the energy band relationship was further analyzed .
It is proved that the composite system effectively expands the light response range and improves the photocatalytic activity . Then , the micro - noble metal is added to the micro - noble metal by hydrothermal process to obtain the M _ 2O2 - BO2 ( OH ) manganese ( M = Ag , Au , Pt ) , and XRD is adopted . The existence of noble metals in the system is confirmed by means of SEM and UV - Vis diffuse reflection . In the same way , the light response range of the system is expanded , and the photocatalytic activity is improved .
secondly , using the relationship between the specific surface area and the photocatalytic degradation rate of the sample , the intrinsic photocatalytic rate of the Bi _ 2ZnOB2O6 is obtained ;
Finally , the energy band position and dipole moment are determined by the structural analysis , the mechanism of promoting carrier separation is analyzed , and the root cause of high intrinsic photocatalytic activity is obtained . The fifth chapter summarizes the work of this thesis , analyzes the innovations and shortcomings in the work , and probes into the future work plan and prospects .

【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ128.54

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