本文選題：光催化劑 + 氮化碳��； 參考：《江蘇大學(xué)》2017年碩士論文

【摘要】：在日益嚴峻的能源危機形勢下,人們對以較低成本就能夠獲得較高能源方法的關(guān)注越來越多,其中光催化技術(shù)就是一種簡單、綠色、低成本的能源儲存與轉(zhuǎn)化技術(shù)。盡管,目前對光催化技術(shù)的研究已經(jīng)取得了很大的進步,但是光催化技術(shù)的產(chǎn)業(yè)化應(yīng)用仍受到限制。這促使人們不斷嘗試研發(fā)高穩(wěn)定、高效率、低成本及綠色環(huán)保的光催化劑。目前,已經(jīng)商業(yè)化的光催化劑只有TiO2,但TiO2只能吸收紫外光,對太陽能的利用率很低。因此很有必要開發(fā)在可見光區(qū)域發(fā)揮作用的新型光催化劑,以便于更好的利用太陽能�？茖W(xué)家們已經(jīng)開發(fā)出了一些新型的可見光響應(yīng)的光催化材料,如銀系催化劑和鉍系催化劑等一些新型的光催化材料�？茖W(xué)家們研究發(fā)現(xiàn),可通過復(fù)合、摻雜、改性等方式,拓寬半導(dǎo)體的吸光范圍,及提升光催化活性。本論文便是采用半導(dǎo)體相互復(fù)合的方式,研究了一系列氮化碳復(fù)合材料的光催化性能及它們之間的構(gòu)效關(guān)系。本論文以石墨相氮化碳(g-C_3N_4)為基材,分別與Ag-Ag_2O、GO/MoS_2和GO/Ag_3PO_4復(fù)合,合成了Ag-Ag_2O/g-C_3N_4、GO/Ag_3PO_4/g-C_3N_4和GO/MoS_2/g-C_3N_4三類三元復(fù)合光催化劑,并對它們各自的結(jié)構(gòu)進行了一系列表征,通過光催化降解甲基橙和RhB考察它們的光催化活性,進一步通過活性物種捕獲實驗探索了各個體系的光催化反應(yīng)機理。主要內(nèi)容如下:(1)通過煅燒法制備了g-C_3N_4,并采用化學(xué)沉淀法合成出Ag-Ag_2O/g-C_3N_4三元復(fù)合光催化劑。采用XRD、SEM、HR-TEM、FT-IR、XPS、DRS等對其進行一系列的表征。其中XRD結(jié)果表明Ag-Ag_2O/g-C_3N_4中含有單質(zhì)Ag、Ag_2O和g-C_3N_4這三類物質(zhì)。SEM、HR-TEM分析結(jié)果顯示在Ag-Ag_2O和g-C_3N_4之間存在異質(zhì)結(jié)構(gòu)。DRS分析發(fā)現(xiàn)與g-C_3N_4相比,Ag-Ag_2O/g-C_3N_4復(fù)合材料在可見光區(qū)的吸收增強。光催化降解實驗結(jié)果表明,在可見光照射3.5 h后,50 wt%Ag-Ag_2O/g-C_3N_4對甲基橙的降解率達到了89.5%,降解效率是g-C_3N_4的7.5倍。根據(jù)能帶理論提出了Ag-Ag_2O/g-C_3N_4復(fù)合光催化劑降解甲基橙的反應(yīng)機理。并通過捕獲實驗進一步證明了空穴起主要的作用。構(gòu)效關(guān)系研究表明Ag-Ag_2O與g-C_3N_4形成了異質(zhì)結(jié)構(gòu),有利于光生載流子的遷移,從而提升光催化活性。(2)通過化學(xué)沉淀法將GO、Ag_3PO_4和g-C_3N_4復(fù)合制備出GO/Ag_3PO_4/g-C_3N_4三元復(fù)合光催化劑。采用XRD、FT-IR、Raman、SEM、XPS、DRS等對其結(jié)構(gòu)及形貌進行一系列的表征。XRD、FT-IR和Raman表明復(fù)合材料由GO、Ag_3PO_4和g-C_3N_4組成。SEM分析結(jié)果顯示GO對Ag_3PO_4有切割作用,能使Ag_3PO_4形成具有規(guī)整形貌的小顆粒。DRS分析發(fā)現(xiàn)GO/Ag_3PO_4的引入拓寬了g-C_3N_4在可見光區(qū)的吸收。光催化降解實驗結(jié)果表明,在可見光照射下50 min后,最佳比例50 wt%GO/Ag_3PO_4/g-C_3N_4在對RhB的降解率達到了94.8%,相對于Ag_3PO_4、g-C_3N_4及1 wt%GO/Ag_3PO_4分別提高了79.1%、88.8%和30.4%。通過捕獲實驗研究了GO/Ag_3PO_4/g-C_3N_4在降解過程中的活性物種,發(fā)現(xiàn)空穴和超氧自由基起主要作用,并對其機理進行了合理的解釋。(3)通過水熱法將GO、MoS_2和g-C_3N_4復(fù)合制備出GO/MoS_2/g-C_3N_4三元復(fù)合光催化劑。采用XRD、FT-IR、Raman、SEM、XPS、DRS等對其形貌及結(jié)構(gòu)進行一系列的表征。其中XRD、FT-IR和Raman分析表明復(fù)合材料由GO、MoS_2和g-C_3N_4組成。SEM、TEM和HR-TEM顯示GO/MoS_2緊緊負載在g-C_3N_4的表面。光催化降解實驗結(jié)果表明,在可見光照射5 h后,3 wt%GO/MoS_2/g-C_3N_4對RhB的降解成效達到了96.7%,相比于g-C_3N_4、MoS_2和5 wt%GO/MoS_2分別提高了20.5%、85.0%和30.5%。PT、EIS和PL測試表明GO/MoS_2/g-C_3N_4具有比g-C_3N_4更強的光生電子和空穴的分離能力。循環(huán)實驗證實了該催化劑具有很好的穩(wěn)定性。通過捕獲實驗和ESR探討了體系的活性物種,并闡明了反應(yīng)機理。
[Abstract]:In the increasingly severe energy crisis, more and more attention has been paid to the ability to obtain higher energy methods at lower costs. Photocatalytic technology is a simple, green, low-cost energy storage and conversion technology. Although the research on photocatalytic technology has made great progress, photocatalytic technology Industrial applications are still limited. This has prompted a continuous attempt to develop high stability, high efficiency, low cost and green photocatalyst. Currently, commercialized photocatalysts have only TiO2, but TiO2 can only absorb ultraviolet light, and the utilization of solar energy is very low. Therefore, it is necessary to develop a new type of photocatalyst in the visible light region. Photocatalysts have been developed to make better use of solar energy. Scientists have developed new photocatalytic materials, such as silver and bismuth catalysts, for photocatalytic materials such as silver and bismuth systems. Scientists have found that the absorption range of semiconductors can be widened by the methods of composite, doping and modification. In this paper, the photocatalytic properties of a series of carbon nitride composites and their structure-activity relationship have been studied by using semiconductor composites. In this paper, graphite phase carbon nitride (g-C_3N_4) was used as the substrate, and Ag-Ag_2O/g-C_3N_4, GO/Ag_3PO_4/g-C_, and GO/ Ag_3PO_4 were synthesized, and Ag-Ag_2O/g-C_3N_4, GO/Ag_3PO_4/g-C_ were synthesized. 3N_4 and GO/MoS_2/g-C_3N_4 three kinds of composite photocatalysts, and their respective structures are characterized by a series of characterization. Photocatalytic activity of methyl orange and RhB is investigated by photocatalytic degradation of methyl orange and RhB. The photocatalytic reaction mechanism of each system is further explored through the capture experiments of active species. The main contents are as follows: (1) through the calcination method The Ag-Ag_2O/g-C_3N_4 three element composite photocatalyst was synthesized by chemical precipitation method. A series of characterization was carried out with XRD, SEM, HR-TEM, FT-IR, XPS, DRS and so on. The XRD results showed that Ag-Ag_2O/g-C_3N_4 contained the Ag, Ag_2O, and these three kinds of substances. The heterostructure.DRS analysis found that the absorption of Ag-Ag_2O/g-C_3N_4 composite in visible light region was enhanced compared with g-C_3N_4. The results of photocatalytic degradation showed that after 3.5 h of visible light, the degradation rate of 50 wt%Ag-Ag_2O/g-C_3N_4 to methyl orange was 89.5% and the degradation efficiency was 7.5 times of g-C_3N_4. According to energy band theory, A was proposed. The reaction mechanism of g-Ag_2O/g-C_3N_4 composite photocatalyst degradation of methyl orange was further demonstrated by the capture experiment. The structure effect relationship studies showed that Ag-Ag_2O and g-C_3N_4 formed a heterogeneous structure, which was beneficial to the migration of light carriers and thus enhanced the photocatalytic activity. (2) GO, Ag_3PO_4 and g- were deposited by chemical precipitation. GO/Ag_3PO_4/g-C_3N_4 three element composite photocatalyst was prepared by C_3N_4 composite. The structure and morphology of the composite were characterized by XRD, FT-IR, Raman, SEM, XPS, DRS, etc. The small particle.DRS analysis showed that the introduction of GO/Ag_3PO_4 widened the absorption of g-C_3N_4 in the visible light region. The results of photocatalytic degradation showed that the optimum ratio of 50 wt%GO/Ag_3PO_4/g-C_3N_4 to RhB was 94.8% after 50 min, compared with Ag_3PO_4, g-C_3N_4 and 1 wt%GO/Ag_3PO_4, respectively, by 79.1. %, 88.8% and 30.4%. have studied the active species of GO/Ag_3PO_4/g-C_3N_4 in the degradation process through the capture experiment, found the main function of the cavitation and superoxide radicals, and explained the mechanism reasonably. (3) the composite photocatalyst of GO/ MoS_2/g-C_3N_4 three elements was prepared by the hydrothermal method, GO, MoS_2 and g-C_3N_4 were prepared by the hydrothermal method. XRD, FT-IR, Ram were used. The morphology and structure of an, SEM, XPS, and DRS were characterized. The XRD, FT-IR and Raman analysis showed that the composite was made up of GO, MoS_2 and g-C_3N_4, which was tightly loaded on the surface. The photocatalytic degradation experiment showed that the degradation was 3 after the visible light irradiation was 5. The results reached 96.7%. Compared with g-C_3N_4, MoS_2 and 5 wt%GO/MoS_2 were increased by 20.5%, 85% and 30.5%.PT respectively. The EIS and PL tests showed that GO/MoS_2/g-C_3N_4 had the ability to separate the photoelectrons and holes stronger than g-C_3N_4. The cyclic experiment proved that the catalyst had good stability. The system was investigated by the capture experiment and the ESR. Active species and elucidate the mechanism of the reaction.
【學(xué)位授予單位】：江蘇大學(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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