本文關(guān)鍵詞：鈷鋁類水滑石復(fù)合材料的制備及其光催化性能　出處：《華僑大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 鈷鋁水滑石 剝離 重組 硫化鎘 鈦鈮酸 三鈦酸 可見光催化

【摘要】：隨著解決環(huán)境污染日益迫切的需求,半導(dǎo)體光催化降解技術(shù)受到了人們廣泛的關(guān)注。然而,低的量子效率和太陽能利用率等因素制約了多數(shù)半導(dǎo)體的光催化應(yīng)用。因此,設(shè)計(jì)合成新型高效光催化材料仍是當(dāng)前研究的重點(diǎn)。具有光催化活性的層狀化合物可剝離為二維納米片層,作為構(gòu)筑基元與各種客體形成復(fù)合異質(zhì)結(jié),能夠有效地拓展材料的光譜響應(yīng)范圍,抑制載流子的快速復(fù)合,提高材料的光催化效率,因此廣泛應(yīng)用于半導(dǎo)體光催化領(lǐng)域。鈷鋁水滑石(Co Al-LDH)是一種陰離子型層狀化合物,可剝離為帶正電荷的納米片層,能夠與其它合適的半導(dǎo)體復(fù)合,具有較高的可見光催化活性。本文選用Co Al-LDH為研究對(duì)象,采用剝離 重組法,將帶正電的LDHs納米片層分別與帶負(fù)電的Cd S納米顆粒、Ti Nb O5-納米片層和Ti3O72-納米片層復(fù)合,利用靜電作用自組裝構(gòu)筑了介孔復(fù)合材料。采用XRD,SEM,TEM,PL,UV-vis DRS,XPS,N2等溫吸附 脫附曲線及光電化學(xué)測試等多種手段對(duì)材料進(jìn)行了表征,通過測定材料在可見光下對(duì)目標(biāo)污染物的降解效率來評(píng)價(jià)光催化活性,并研究了相應(yīng)的光催化作用機(jī)制。(1)Cd S/Co Al-LDH柱撐復(fù)合材料的制備與表征。將剝離的LDHs片層與Cd S顆粒溶膠混合,制備出Cd S柱撐的Cd S/Co Al-LDH復(fù)合材料。該材料為介孔結(jié)構(gòu),比表面積為62 m2·g-1,層間通道高度2.14 nm。在可見光照射下,復(fù)合材料對(duì)酸性紅染料具有較高的催化活性,180 min內(nèi)降解90%,是Co Al-LDH和Cd S的2倍多。同時(shí),復(fù)合材料展現(xiàn)出良好的光催化循環(huán)穩(wěn)定性。(2)Co Al-Ti Nb O5間層復(fù)合材料的制備與表征。以窄帶隙半導(dǎo)體Co Al-LDH和寬帶隙半導(dǎo)體HTi Nb O5剝離的納米片層作為構(gòu)筑基元,形成了片層相間堆積的復(fù)合材料。該材料為多級(jí)介孔結(jié)構(gòu),比表面積增大為46 m2·g-1,兩組分間緊密接觸,具有較強(qiáng)的電子耦合效應(yīng),拓寬了光響應(yīng)范圍,加速了載流子的傳導(dǎo)分離。Co Al-Ti Nb O5復(fù)合材料對(duì)酸性紅染料的催化活性分別是Co Al-LDH和HTi Nb O5的3.2倍和17.8倍,光催化循環(huán)穩(wěn)定性良好。(3)Co Al-Ti3O7間層復(fù)合材料的制備與表征。Co Al-LDH和H2Ti3O7納米片層靜電作用自組裝得到Co Al-Ti3O7復(fù)合材料,兩組分緊密結(jié)合,無序堆積形成類卡片房式結(jié)構(gòu),孔徑出現(xiàn)多級(jí)分布,比表面積增大為67 m2·g-1。在增大的比表面積和兩者形成的Z型異質(zhì)結(jié)協(xié)同效應(yīng)下,Co Al-Ti3O7復(fù)合材料對(duì)羅丹明B的可見光催化降解效率分別是Co Al-LDH和H2Ti3O7的6.6倍和3.8倍,表現(xiàn)出較好的光催化循環(huán)穩(wěn)定性。
[Abstract]:With the increasing demand for environmental pollution, the photocatalytic degradation technology of semiconductor has attracted wide attention. However, the low quantum efficiency and the utilization of solar energy have restricted the photocatalytic application of most semiconductors. Therefore, the design and synthesis of novel high photocatalytic materials are still the focus of current research. Layered compounds with photocatalytic activity can be stripped for two-dimensional nano sheets as building elements and objects to form a composite heterojunction, can effectively expand the material spectral response range, suppression of carrier fast composite, improve the photocatalytic efficiency of materials, so it is widely used in the field of semiconductor photocatalysis. Cobalt aluminum hydrotalcite (Co Al-LDH) is an anionic layered compound, which can be stripped to a positively charged nanoscale layer. It can be combined with other suitable semiconductors and has high visible light photocatalytic activity. In this paper, Co Al-LDH is chosen as the research object. The LDHs Nanoplates with positive electricity are combined with negatively charged Cd S nanoparticles, Ti Nb O5- nanosheets and Ti3O72- nanosheets, respectively. The mesoporous composites are fabricated by electrostatic interaction. Using XRD, SEM, TEM, PL, UV-vis, DRS, XPS, N2 adsorption desorption curves and photoelectric chemical testing and other means of materials were characterized, the photocatalytic activity was evaluated by measuring the material degradation efficiency of target pollutants under visible light, and the photocatalytic mechanism of the corresponding. (1) preparation and characterization of Cd S/Co Al-LDH pillared composites. The Cd S pillared Cd S/Co Al-LDH composite was prepared by mixing the stripped LDHs layer with the Cd S granular sol. The material is mesoporous structure with a specific surface area of 62 m2. G-1, and the height of interlaminar channel is 2.14 nm. Under the light of visible light, the composite has high catalytic activity for acid red dye and 90% in 180 min, which is more than 2 times as much as Co Al-LDH and Cd S. At the same time, the composite exhibits good stability of the photocatalytic cycle. (2) preparation and characterization of Co Al-Ti Nb O5 interlayer composites. Nanoscale lamellae stripped with narrow band gap semiconductor Co Al-LDH and broadband gap semiconductor HTi Nb O5 are used as the construction elements to form a composite material that is stacked interphase. The material is multi-stage mesoporous structure with the specific surface area increased to 46 m2. G-1. The two components are closely contacted, which has strong electronic coupling effect. It broadens the light response range and accelerates the conduction and separation of carriers. The catalytic activity of Co Al-Ti Nb O5 composite for acid red dye is 3.2 times and 17.8 times as much as Co Al-LDH and HTi Nb O5, and the stability of the photocatalytic cycle is good. (3) preparation and characterization of Co Al-Ti3O7 interlayer composites. Co Al-LDH and H2Ti3O7 nanoscale layers were self assembled to achieve Co Al-Ti3O7 composites. The two components were closely combined, forming a card like room structure with disorder stacking. The pore size was distributed at multiple levels, and the specific surface area increased to 67 m2 / g-1. Under the synergistic effect of the increased specific surface area and the Z heterojunction formed by them, the visible light photocatalytic degradation efficiency of Co Al-Ti3O7 composite for rhodamine B is 6.6 times and 3.8 times of that of Co Al-LDH and H2Ti3O7, showing better photocatalytic cycle stability.
【學(xué)位授予單位】：華僑大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：O643.36
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本文編號(hào)：1337958