ZnO/CuO/CNTs复合材料的制备及性能

以醋酸锌、醋酸铜和纯化的碳纳米管(CNTs)为原料利用溶胶-凝胶法,制备氧化锌(ZnO)、氧化铜(CuO)和ZnO/CuO/CNTs光催化剂。通过紫外-可见漫反射(DRS)、扫描电子显微镜(SEM)、光致发光(PL)等对复合材料的结构、能带间隙以及光学性质进行表征。研究了ZnO/CuO/CNTs光催化剂在紫外光和太阳光的照射下降解甲基橙等染料的光催化降解情况。结果表明ZnO/CuO/CNTs的光催化活性明显高于ZnO/CuO,在可见光照射下光照3h后,降解率达到80%以上。     

MOF衍生的多孔ZnO/C、Ag/ZnO/C复合材料光催化性能研究

以金属有机骨架(MOF-5)为前驱体, 通过高温热处理和湿化学法获得ZnO/C和Ag/ZnO/C两种光催化复合材料。采用X 射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDS)和紫外-可见分光漫反射(UV-Vis DRS)等方法对所得样品的晶体结构、形貌特征、组成及光谱特性进行了表征。结果显示, 高温热处理保留了MOF-5的原始结构。ZnO/C比表面积为390 m²/g, 载银后比表面积仍达232 m²/g, 负载的银颗粒尺寸约30 nm。光催化降解实验表明ZnO/C和Ag/ZnO/C复合材料对亚甲基蓝(MB)都具有很高的降解效率, 均优于商业TiO₂。Ag/ZnO/C的光催化性能更好, 且具有较好的重复利用和稳定性。因此, 适度的高温碳化和掺杂贵金属是获得优良光催化性能的根本原因。     

Ag-TiO_2/CNTs的复合及光催化性能

以钛酸四丁酯、硝酸银、碳纳米管为原料,通过溶胶-凝胶法制备了系列不同碳纳米管含量和热处理温度下的掺银TiO2颗粒/碳纳米管(Ag-TiO2/CNT)的复合催化剂,以甲基橙为目标降解物考察复合物的光催化活性。利用X-射线衍射(XRD),透射电子显微镜(TEM)和电子探针能谱仪(EDS)对所制的Ag-TiO2/CNTs复合材料进行了表征。结果表明:掺银TiO2颗粒在碳纳米管上均匀分布,所制复合材料具有较高的光催化性能。不同的热处理温度决定着催化效率的高低,在实验条件下,当热处理温度为600℃时,复合物的光催化活性较高。随碳纳米管含量的增加,催化活性逐渐增大,当碳纳米管的负载量在3.5%(碳纳米管/TiO2,重量百分比)时,催化活性达到最大值,超过该比例时,催化活性反而呈下降趋势。在600℃、碳纳米管负载量3.5%时,复合物光催化活性最高,降解率达90%以上。     

RGO/ZnO纳米棒复合材料的合成及光催化性能

采用水热合成法制备ZnO纳米棒及RGO/ZnO纳米棒复合材料。研究不同含量的RGO对RGO/ZnO纳米棒复合材料光催化活性的影响。采用X射线衍射仪(XRD)、场发射电子显微镜(FESEM)、光电子能谱仪(XPS)及漫反射紫外-可见吸收光谱(UV-Vis)检测手段对RGO/ZnO进行表征。结果显示:RGO与ZnO纳米棒成功复合。加入GO的含量不同,获得的RGO/ZnO样品在可见光区域的吸光度值不同。以甲基橙作为模拟污染物的光催化结果表明,RGO/ZnO复合材料具有高的紫外-可见光光降解效率,加入GO与ZnO的质量比为3%时,样品紫外-可见光光催化性能最佳,120min内甲基橙基本可以完全降解;且在波长大于400nm可见光照射下,RGO/ZnO具有一定的可见光活性,180min内其降解甲基橙效率最大可达26.2%。同时,RGO/ZnO具有较好的光稳定性。     

纳米TiO2-Pt复合材料的制备及在可见光下的光催化性能研究

采用低温水热法制备纳米棒状锐钛矿相TiO₂溶胶,以氯铂酸为Pt源,通过贵金属沉积制备不同含量Pt的纳米TiO₂-Pt复合材料。通过X射线衍射、扫描电子显微镜、透射电子显微镜、紫外可见吸收光谱、X射线光电子能谱分析对纳米TiO₂-Pt复合材料的表面形貌和光学性质进行了表征,利用氙灯照射模拟可见光光源对亚甲基蓝(MB)水溶液进行光催化反应降解,通过溶液前后吸光度值的变化来准确评价实验材料的光催化活性。结果表明：制备的二氧化钛溶胶尺寸均一,为标准的锐钛矿型;且Pt纳米粒子很好地分散于TiO₂表面,正是由于铂层的存在,有效抑制了光生电子-空穴的复合,延长了光生载流子的工作寿命,提升了量子效能,使TiO₂-Pt的光催化活性远高于普通TiO₂,对亚甲基蓝的光降解效果也达到了88.5%。     

氟、锌共掺杂TiO_2纳米晶的制备与光催化性能

采用溶胶-凝胶法制备了氟、锌共掺杂TiO2纳米晶光催化剂,分别利用X射线衍射(XRD)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和紫外-可见(UV-Vis)漫反射光谱对样品进行表征,并通过降解亚甲基蓝实验评估了样品的光催化性能。XRD与TEM表征结果表明,样品为锐钛矿相,平均粒径约16nm。掺杂后,样品光吸收性能未得到显著改善,但其光催化活性却得到显著提高。掺杂离子F-有利于光催化反应过程中羟基自由基的形成,样品光催化活性因而得到显著提高;共掺杂样品中,随着Zn掺杂量的增加,样品光催化活性呈现先增加后减小的变化趋势,Zn掺杂量为2%时,共掺杂样品的光催化性能最佳。     

Ce掺杂ZnO/膨润土复合光催化材料的制备及其性能

以膨润土为载体,硝酸锌、硝酸铈和氢氧化钠为原料,采用沉淀法制备了Ce掺杂ZnO/膨润土复合光催化材料.利用X射线衍射(XRD)、红外光谱仪(FT-IR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、氮气吸附仪等对其进行表征,并通过对亚甲基蓝(MB)溶液脱色反应,考察紫外光照射下复合材料的光催化性能.结果表明,复合光催化材料中由于Ce掺杂ZnO的光催化作用与膨润土的吸附性相互协同,显示出优良的光催化活性和稳定性.当Ce的掺杂量为3.0%,同时复合光催化材料的加入量为20 mg/L,MB溶液的pH值为6时,复合光催化材料的性能最优,在紫外灯下照射2 h后,MB溶液的脱色率达到98.6%.     

GaN/ZnO复合体的制备及光催化性能

首先用聚乙烯吡咯烷酮(PVP)作为表面活性剂, 硝酸镓[Ga(NO₃)₃]作为镓源, 采用溶胶-凝胶法制备了GaN粉末。然后通过固相法将GaN粉末和ZnO粉末按不同配比机械混合, 制备成GaN/ZnO复合体。采用X射线粉末衍射(XRD)、扫描电镜(SEM)、X射线能谱 (EDS)、高分辨透射电子显微镜(HRTEM)和发致光谱(PL)表征GaN/ZnO复合体的微结构、形貌、成分和发光特性, 并将其作为催化剂进行降解亚甲基蓝水溶液的光催化性能测试。结果表明: GaN/ZnO复合体对比未经复合的GaN和ZnO粉末, 光催化性能有明显的增强。基于一级动力学方程分析, 当GaN/ZnO复合体中GaN粉末和ZnO粉末含量配比为1: 2时, 光催化性能达到最佳, 其速率常数k值为0.11 min^-1。     

纳米ZnO/电气石复合粉体的制备及其对亚甲基蓝光催化性能的研究

以NaOH、ZnSO4·7H2O和电气石为原料,采用室温固相法制备纳米ZnO/电气石复合粉体。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)对复合粉体的物相及形貌进行了表征,并考察了复合粉体对亚甲基蓝的光催化降解性能。实验结果表明,纳米ZnO可紧密地包覆在电气石表面形成ZnO/电气石复合粉体。光催化降解实验、紫外-可见漫反射光谱、荧光光谱分析等测试表明,添加电气石粉体可有效地提高ZnO/电气石复合粉体的光吸收能力、荧光发射能力以及对亚甲基蓝的光催化降解性能。     

Ag-CNT/TiO_2复合电极对亚甲基蓝的光电催化降解作用(英文)

采用金属银修饰的碳纳米管制备了Ag-CNT/TiO2复合电极。利用X-射线衍射(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM),和能量分散性X射线分析(EDX)对所制的Ag-CNT/TiO2复合材料进行了表征。结果表明:二氧化钛颗粒和金属银颗粒在碳纳米管上均匀分布,所制电极具有较高的光电催化性能。其对亚甲基蓝的光电催化降解归因于一种协同效应,即二氧化钛的光降解、碳纳米管网络的电子辅助、金属银的增强和外加电势的作用。尤其是,经银修饰的复合电极增强了其对亚甲基蓝的光电降解,且随银含量的增加其光电催化效果增加。     

Growth and characterization of flower-like Ag/ZnO heterostructure composites with enhanced photocatalytic performance

Flower-like Ag/ZnO heterostructure composites were prepared through a solvothermal method without surfactants or templates. The products were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence (PL) spectroscopy. Results demonstrate that flower-like Ag/ZnO heterostructure composites were composed of wurtzite ZnO flowers coated by face-center-cubic Ag nanoparticles. The growth process of flower-like ZnO crystals was investigated, and a possible growth mechanism was proposed. The photocatalytic activity of the as-prepared flower-like Ag/ZnO samples, pure ZnO samples, and commercial TiO₂ (Degussa, P-25) was tested with the photocatalytic degradation of methylene blue. Results show that the Ag/ZnO heterostructures were superior in photocatalytic activity to the pure ZnO samples and the commercial TiO₂ (Degussa, P-25), but the mixture of Ag (0.1 wt%) particles and ZnO flowers did not, which implies that the heterostructure promoted the separation of photogenerated electron–hole pairs, enhancing the photocatalytic activity. That was primarily verified by the PL results.     

Visible light photocatalytic properties of novel molybdenum treated carbon nanotube/titania composites

Two types of molybdenum–carbon nanotubes and molybdenum treated carbon nanotubes/titania composites were prepared using a sol–gel method. These composites were characterized comprehensively by the Brauer–Emett–Teller (BET) surface area, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis absorption spectroscopy. It was found that the photocatalytic degradation of a methylene blue solution could be attributed to the combined effects caused by the photo-degradation of titania, the electron assistance of carbon nanotube network, and the enhancement of molybdenum. The proposed redox mechanism of the photodegradation of methylene blue on Mo-CNT/TiO₂ composites is suggested.     

Preparation of novel CdS-graphene/TiO2 composites with high photocatalytic activity for methylene blue dye under visible light

In this study, CdS combined graphene/TiO₂ (CdS-graphene/TiO₂) composites were prepared by a sol–gel method to improve on the photocatalytic performance of TiO₂. These composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM). The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible light irradiation. The photodegradation rate of MB under visible light irradiation reached 90·1% during 150 min. The kinetics of MB degradation were plotted alongside the values calculated from the Langmuir–Hinshelwood equation. 0·1 CGT sample showed the best photocatalytic activity, which was attributed to a cooperative reaction between the increase of photo-absorption effect by graphene and photocatalytic effect by CdS.     

Fabrication and photocatalytic property of ZnO nanorod arrays on Cu2O thin film

ZnO nanorod arrays were fabricated on Cu₂O thin film by a simple low-temperature liquid-phase-deposition method. The samples were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FESEM). The UV-Vis spectroscopy showed that the obtained sample was able to absorb a large part of visible light (up to 650 nm). Their photocatalytic activities were investigated by degradation of dye methylene blue (MB) under UV-Vis and visible light irradiation. It was found that the photocatalytic activity of the ZnO/Cu₂O NRs was higher than the ZnO/ZnO NRs under UV-Vis light. In a word, Cu₂O played an important role in enhancing the photocatalytic activity of the ZnO/Cu₂O NRs.     

Preparation of Fe-doped TiO2 nanotube arrays and their photocatalytic activities under visible light

Fe-doped TiO₂ nanotube arrays have been prepared by the template-based liquid phase deposition method. Their morphologies, structures and optical properties were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and UV-vis absorption spectroscopy. Their photocatalytic activities were evaluated by the degradation of methylene blue under visible light. The UV-vis absorption spectra of the Fe-doped TiO₂ nanotube arrays showed a red shift and an enhancement of the absorption in the visible region compared to the undoped sample. The Fe-doped TiO₂ nanotube arrays exhibited good photocatalytic activities under visible light irradiation, and the optimum dopant amount was found to be 5.9 at% in our experiments.     

Self-assembly of the Ag deposited ZnO/carbon nanospheres: A resourceful photocatalyst for efficient photocatalytic degradation of methylene blue dye in water

Carbon nanospheres (CNSs) are synthesized by pyrolysis of benzene at 1000?°C. Various UV-light photocatalysts of ZnO/CNSs and Ag-ZnO/CNSs (AZCN) composites are synthesized on the surface of CNSs using a facile chemical precipitation method. Morphological and optical properties of the as-synthesized photocatalysts are characterized by scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy, UV-Vis spectroscopy, photoluminescence and Raman spectroscopy. Photocatalytic degradation efficiency of methylene blue dye is investigated to examine the photocatalytic activity of synthesized photocatalysts. It is found that as-synthesized ZnO/CNSs composite can degrade higher methylene blue dye (～85.6%) after 25?min of UV irradiation in comparison with that of CNSs. A prominent improvement in the photodegradation is attained by depositing metal (Ag) particles on the surface of ZnO/CNSs composite. AZCN composite displays the enhanced photocatalytic degradation performance (～95% after 15?min of UV light) in high concentration of methylene blue dye. Furthermore, stability performance is studied by recycling the AZCN composite photocatalyst. It is found that the photocatalytic activity of AZCN composite is only slightly decreased even after five cycles. Present work demonstrates that AZCN composite show a great potential in the treatment of organic pollutants for wastewater treatment.     

Synthesis and characterization of M-fullerene/TiO2 photocatalysts designed for degradation azo dye

Metal-fullerene/TiO₂ composites were prepared using a sol–gel method, and their photocatalytic activity was evaluated by degradation of methylene blue (MB) solutions under UV light. The surface area, surface structure, crystal phase and elemental identification of these composites were characterized by Brunauer–Emmett–Teller analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction and transmission electron microscopy, respectively. The degradation effect of MB was determined using UV/Vis spectrophotometry. Photocatalytic activity was increased because of the increase in photo-absorption effect by fullerene, and the cooperative effect of the metal introduced as a dopant.     

Enhanced photocatalytic activity of ZnO/CuO nanocomposite for the degradation of textile dye on visible light illumination

The photocatalytic degradation of organic dyes such as methylene blue and methyl orange in the presence of various percentages of composite catalyst under visible light irradiation was carried out. The catalyst ZnO nanorods and ZnO/CuO nanocomposites of different weight ratios were prepared by new thermal decomposition method, which is simple and cost effective. The prepared catalysts were characterized by different techniques such as X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and UV–visible absorption spectroscopy. Further, the most photocatalytically active composite material was used for degradation of real textile waste water under visible light illumination. The irradiated samples were analysed by total organic carbon and chemical oxygen demand. The efficiency of the catalyst and their photocatalytic mechanism has been discussed in detail.