MOFs衍生TiO2/杂多酸复合材料的制备及光催化性能

采用一锅法制备了金属有机框架 MIL-125（Ti）包裹的磷钼酸（HPMo）,并以其为前驱体,制备得到 HPMo/TiO₂复合材料,利用傅里叶红外光谱（FT-IR）、X 射线衍射分析（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）及 N₂-吸附脱附等对其结构和形貌进行表征,结果发现 HPMo/TiO₂复合材料主要表现为介孔结构,且具有较大的比表面积。在可见光照射下,研究了HPMo/TiO₂复合材料对罗丹明B溶液的光催化降解,数据显示,可见光照射90 min 后,罗丹明 B 溶液的降解率达 89.6%,且重复使用 3 次后仍保持较好的催化效果。此外,HPMo/TiO₂复合材料还适用于催化降解其它有机染料。     

硫酸根对聚合氮化碳光催化活性的影响

在pH=1条件下分别加入硫酸根、硝酸根、磷酸根对三聚氰胺进行处理,采用高温煅烧法制备了一系列聚合氮化碳材料,并通过X射线衍射（XRD）、扫描电子显微镜（SEM）、紫外-可见漫反射光谱（UV-Vis DRS）等分析手段对样品进行了表征。以罗丹明B（RhB）为污染物,探究了在可见光下聚合氮化碳对RhB的光催化降解性能、稳定性以及降解机理。加入0.12 mol硫酸根处理的聚合氮化碳（CN-0.04SO₄^2-）在45 min内对RhB的降解率为99.1%,其伪一级动力学常数是未加硫酸根的23.0倍,硫酸根能有效地增强聚合氮化碳的光催化活性。CN-0.04SO₄^2-经过3次循环实验对RhB的降解率略有下降,说明其具有良好的稳定性。活性物种捕获实验表明,影响光催化降解RhB的主要活性物种是·O₂^-和·OH。     

稀土掺杂TiO2的光催化性能研究

以钛酸丁酯、无水乙醇、冰乙酸为原料,以罗丹明B为模拟有机污染物,采用溶胶-凝胶法制备了一系列的TiO₂光催化剂,并利用XRD和物理吸附对催化剂进行了表征。考察了原料配比、凝胶时间、稀土掺杂种类、稀土掺杂量对TiO₂光催化罗丹明B性能的影响。结果表明：当钛酸比为1.5∶1、钛醇比为2∶1、凝胶时间为48 h、Pr掺杂量为2%时,TiO₂光催化罗丹明B的降解率最好。在光催化条件为罗丹明B初始质量浓度为4 mg·L^-1、催化剂质量0.05 g、光反应时间6 h时,罗丹明B的降解率达93.23%。     

复合催化剂Ag-Ti/碳纤维的制备及光催化降解罗丹明B

本文采用乙酸钛、AgNO₃和碳纤维为原料,通过溶胶-凝胶法制备了新型Ag/TiO₂负载碳纤维光催化材料。通过XRD、SEM观察了微观形貌和结构。研究发现,所制备的复合光催化材料结晶性能良好,由于Ag的加入,复合光催化材料晶粒细化,催化活性更高。探讨了光催化剂对罗丹明B溶液降解效果的影响,发现当催化剂的用量为0.30g·L^-1、罗丹明B溶液的浓度为6mg·L^-1时,在Ag掺杂比为Ag/TiO₂=2∶1的复合光催化剂情况下,其降解活性最高,可达到88%以上,为解决染料废水的治理提供技术支持。     

SBA-15/Ni/TiO2/CNTs复合材料的制备及其光催化性能

通过溶胶凝胶法,经多次涂覆在SBA-15上负载掺杂镍的纳米TiO₂,得到SBA-15/NiO/TiO₂复合物;再以TiO₂中还原态金属镍为催化剂,通过化学气相沉积法（CVD）,在SBA-15/NiO/TiO₂表面原位生长碳纳米管,制得SBA-15/Ni/TiO₂/CNTs复合材料。通过XRD、SEM、TEM、UV-Vis和Raman等方法考察了SBA-15/Ni/TiO₂/CNTs复合材料的结构和性能,并通过降解亚甲基蓝溶液评价其光催化活性。结果表明,SBA-15/Ni/TiO₂/CNTs复合光催化剂的催化活性较SBA-15/NiO/TiO₂显著提高。 二次涂覆掺杂镍的二氧化钛制得的复合光催化剂的催化活性高于一次涂覆。     

Pr3+:Y2SiO5/TiO2上转换复合膜光催化性能

为解决悬浮相TiO₂粉体处理水中污染物后难以分离和回收利用的缺点并进一步提高纳米TiO₂对太阳光的利用率,采用溶胶-凝胶法制备了Pr³⁺:Y₂SiO₅粉体、TiO₂薄膜以及Pr³⁺:Y₂SiO₅/TiO₂复合膜。利用XRD、SEM等表征方法对样品进行表征。重点考察了Pr³⁺:Y₂SiO₅/TiO₂复合材料薄膜对亚甲基蓝的光催化降解效率与镀膜层数等因素的关系。结果发现涂覆5层Pr³⁺:Y₂SiO₅/TiO₂复合膜时,降解率可高达95.7%,其对应的第2次和第3次降解率分别为82.46%和74.94%;随着Pr³⁺:Y₂SiO₅/TiO₂复合膜薄膜面积的增加降解率先增加后降低,使用8张薄膜时降解率最高达96.43%;增加光照强度有利于提高降解率,但当光照强度增加到100 W时,降解率达到稳定值96.18%;随着初始浓度的增加,降解率逐渐降低。     

TiO2/FACs与TiO2/Mullite复合材料的制备及其光催化性能

分别以粉煤灰漂珠(简记为FACs)与海胆状莫来石球(简记为Mullite)为基体，采用溶胶浸渍工艺制备了TiO₂/FACs与TiO₂/Mullite型复合材料。通过X射线衍射(XRD)、扫描电子显微镜(SEM)以及电子能谱(EDS)对制备的材料进行了表征。研究了TiO₂/FACs与TiO₂/Mullite型复合材料在紫外光照射下对罗丹明B(RhB)的光催化性能。结果表明：经500℃煅烧后形成的锐钛矿型TiO₂均成功负载到粉煤灰漂珠与莫来石晶体上，在粉煤灰漂珠表面覆盖了一层厚薄不均的纳米级别的TiO₂薄膜，而在莫来石晶体上则出现了大量细小的TiO₂颗粒；在降解染料时间为180 min,TiO₂/FACs与TiO₂/Mullite复合材料对罗丹明B染料的降解率分别为84.8%和96.4%，降解速率为0.01088min^-1和0.02885 min^-1。     

SO42-/TiO2-HZSM-5固体超强酸催化剂的制备及酯化性能

采用溶胶-凝胶法制备了HZSM-5分子筛负载SO₄^2-/TiO₂固体超强酸催化剂, 利用直接酯化法催化合成三羟甲基丙烷油酸酯。通过IR、XRD、BET、SEM对催化剂进行了表征, 结果表明TiO₂以纳米颗粒的形式附着于HZSM-5分子筛表面, 且负载后催化剂的比表面积高达309.2m²/g, 比HZSM-5分子筛提高了45.6m²/g, 且催化剂具有强酸性(-13.8< H₀ < -12.14)。探讨了沉淀pH值、焙烧温度、焙烧时间等催化剂制备条件对SO₄^2-/TiO₂-HZSM-5固体超强酸催化剂催化三羟甲基丙烷油酸酯酯化反应活性的影响。结果表明在沉淀pH=8、硫酸的浸渍浓度为0.5mol/L、浸渍时间为30min、焙烧温度为550℃、焙烧时间4h的条件下, SO₄^2-/TiO₂-HZSM-5固体超强酸催化剂催化活性最高, 三羟甲基丙烷油酸酯的酯化率高达97.6%;抗乳化性能良好, 油水分离时间为5min。SO₄^2-/TiO₂-HZSM-5固体超强酸催化剂在重复使用6次的情况下, 酯化率下降8.8%, 催化剂的重复使用性能良好。     

TiO2作用下土霉素的可见光敏化降解

研究了二氧化钛(TiO₂)存在时土霉素(OTC)在可见光下的降解。结果表明：单独可见光照下,OTC的光解效率随着pH的升高而逐渐增大。可见光和TiO₂的联合能显著促进OTC的降解,这主要归因于OTC的自光敏化作用。淬灭实验表明,在可见光/TiO₂体系中,超氧阴离子自由基(O₂^·-)和羟基自由基(·OH)能够氧化降解OTC,且O₂^·-是主要的活性物种。OTC初始浓度会影响其在可见光/TiO₂体系中的降解,过高或过低的OTC浓度都不利于其自身的去除;但是TiO₂用量的增加却能逐渐提高OTC的降解效率。     

Pt/TiO2/ZSM-5催化剂的制备及其催化转化正丁烷

采用溶胶-凝胶法和等体积浸渍法,分别对ZSM-5分子筛进行TiO₂改性和Pt负载,获得了具有脱氢-裂解双功能的Pt/TiO₂/ZSM-5催化剂,采用XRD、N₂吸附-脱附、TEM、XPS和NH₃-TPD对样品的晶体结构,孔结构、形貌、活性金属价态和酸性质等进行了表征,并研究了正丁烷在此催化剂上催化转化制备低碳烯烃的反应规律。研究结果表明,TiO₂的引入,一方面使得改性后的ZSM-5分子筛获得了额外的酸性中心,特别是强酸性位含量的增加,有助于促进正丁烷的活化;另一方面Pt与TiO₂之间存在“金属-载体”强相互作用（SMSI）,在H₂还原气氛下,Pt能够促进TiO₂的还原,生成Ti³⁺物种,而Ti³⁺的存在增加了Pt周围的电荷密度,降低了Pt对低碳烯烃（C₂⁼～C₃⁼）的吸附能力,抑制了深度脱氢和生焦反应,从而提高双功能催化剂对烯烃的选择性。当H₂还原温度为450℃时,Pt/10TiO₂/ZSM-5催化剂在625℃下的正丁烷转化率为76.1%,低碳烯烃（C₂⁼～C₃⁼）收率为50.9%,分别比Pt/ZSM-5催化剂提高了16.7%和12.6%。     

Preparation and characterization of sulfated TiO2 with rhodium modification used in esterification reaction and decomposition of methyl orange☆

A unique Rh/TiO_2 solid acid catalyst modified with H_2SO_4 was synthesized and evaluated in the esterification reaction of propylene glycol methyl ether and decomposition of methyl orange(MO) in aqueous phase under halogen lamp irradiation. For this purpose, rhodium(Rh) nanoparticles were loaded on SO_4~(2-)/TiO_2 via the photo-deposition method. It was found that SO_4~(2-)/Rh–TiO_2 exhibited stronger catalytic activity than SO_4~(2-)/TiO_2. The new catalysts were characterized by X-ray powder diffraction(XRD), Brunauer–Emmett–Teller(BET), Transmission electron microscopy(TEM) and high-resolution(HRTEM), X-ray photoelectron spectroscopy(XPS) and Fourier Transform infrared spectroscopy(FTIR). Results from XRD and BET show that SO_4~(2-)/Rh–TiO_2 has higher specific surface area and smaller pore size than SO42-/TiO_2. The distribution of loaded Rh was found to be uniform with a particle size of 2–4 nm. Data from XPS reveal that Rh primarily exists as Rh~0 and Rh~(3+)in Rh–TiO_2 and SO_4~(2)-/Rh–TiO_2. These valence forms of Rh likely contribute to the enhanced catalytic activity. Furthermore, FT-IR spectra of the catalysts show an abundance of surface hydroxyl groups, which help the formation of hydroxyl radicals and the enhancement of surface acid density. The results show that more acid sites are formed on the sulfated Rh–TiO_2, and these acidic sites are largely responsible for improving the catalytic performance. This superior SO_4~(2-)/Rh–TiO_2 catalyst has potential applications in reactions requiring efficient acid catalysts, including esterification reactions and waste water treatment.     

C/TiO2-SO42-的制备及其光解水性能

通过溶胶-凝胶制备过程中水含量控制,分别获得了硫酸根修饰的TiO₂（25）和无修饰的TiO₂（150）两种二氧化钛载体。在两种载体上,通过浸渍法引入不同浓度的碳点胶体,获得了系列不同C含量的C_x/TiO₂（25）和C_x/TiO₂（150）催化剂。利用TEM、XRD、FT-IR、UV-Vis、BET、XPS等表征分析了催化剂的表面形貌、晶格间距、晶型结构、光吸收、孔结构及元素组成。结果显示：相对于无硫酸根修饰的TiO₂（150）催化剂,硫酸根修饰的TiO₂（25）催化剂的光吸收发生显著红移,展示了更宽的可见光响应;对于TiO₂（25）样品,C的引入可提高其O_ads/O_latt比值。催化性能研究显示,C的引入可以提高其光催化活性。     

Effect of pH, inorganic ions, organic matter and H2O2 on E. coli K12 photocatalytic inactivation by TiO2: Implications in solar water disinfection

The effect of different chemical parameters on photocatalytic inactivation of E. coli K12 is discussed. Illumination was produced by a solar lamp and suspended TiO₂ P-25 Degussa was used as catalyst. Modifications of initial pH between 4.0 and 9.0 do not affect the inactivation rate in the absence or presence of the catalyst. Addition of H₂O₂ affects positively the E. coli inactivation rate of both photolytic (only light) and photocatalytic (light plus TiO₂) disinfection processes. Addition of some inorganic ions (0.2 mmol/l) like HCO₃⁻, HPO₄²⁻, Cl⁻, NO₃⁻ and SO₄²⁻ to the suspension affects the sensitivity of bacteria to sunlight in the presence and in absence of TiO₂. Addition of HCO₃⁻ and HPO₄²⁻ resulted in a meaningful decrease in photocatalytic bactericidal effect while it was noted a weak influence of Cl⁻, SO₄²⁻ and NO₃⁻. The effect of counter ion (Na⁺ and K⁺) is not negligible and can modify the photocatalytic process as the anions. Bacteria inactivation was affected even at low concentrations (0.2 mmol/l) of SO₄²⁻ and HCO₃⁻, but the same concentration does not affect the resorcinol photodegradation, suggesting that disinfection is more sensitive to the presence of natural anions than photocatalytic degradation of organic compounds. The presence of organic substances naturally present in water like dihydroxybenzenes isomers shows a negative effect on photocatalytic disinfection. The effect of a mixture of chemical substances on photocatalytic disinfection was also studied by adding to the bacterial suspension nutrient broth, phosphate buffer and tap water.     

Preparation of Au/TiO2 catalysts from Au(I)–thiosulfate complex and study of their photocatalytic activity for the degradation of methyl orange

Gold loaded on TiO₂ (Au/TiO₂) catalysts were prepared using Au(I)–thiosulfate complex (Au(S₂O₃)₂³⁻) as the gold precursor for the first time. The samples were characterized by UV–vis diffuse reflectance spectra, X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic absorption flame emission spectroscopy (AAS), and X-ray photoelectron spectroscopy (XPS) methods. Using Au(S₂O₃)₂³⁻ as gold precursor, ultra-fine gold nanoparticles with a highly disperse state can be successfully formed on the surface of TiO₂. The diameter of Au nanoparticles increases from 1.8 to 3.0 nm with increasing the nominal Au loading from 1% to 8%. The photocatalytic activity of Au/TiO₂ catalysts was evaluated from the analysis of the photodegradation of methyl orange (MO). With the similar Au loading, the catalysts prepared with Au(S₂O₃)₂³⁻ precursor exhibit higher photocatalytic activity for methyl orange degradation when compared with the Au/TiO₂ catalysts prepared with the methods of deposition–precipitation (DP) and impregnation (IMP). The preparation method has decisive influences on the morphology, size and number of Au nanoparticles loaded on the surface of TiO₂ and further affects the photocatalytic activity of the obtained catalysts.     

新型纳米SO42-/TiO2催化剂制备及催化合成醋酸丁酯

采用高压水热法合成纳米锐钛矿相TiO₂前驱体,通过H₂SO₄溶液浸渍制备系列新型SO₄^2-/TiO₂催化剂,采用XRD、TG-DTG和TEM对其结构和形貌进行表征,并用于催化醋酸与正丁醇的酯化反应,考察H₂SO₄溶液浓度、浸渍时间和反应时间对酯化率的影响。结果表明,在H₂SO₄浓度1 mol·L^-1、浸渍时间12 h和反应时间180 min条件下,酯化率高达99.2%,催化剂具有优异的催化性能和较佳的重复使用性。     

Removal of ammonium ions in wastewater by electrosorption with TiO2 modified graphene electrode

In this study, the TiO₂ modified graphene composite material (RGO/ TiO₂) was prepared by hydrothermal method, and its morphological structure and electrochemical properties were investigated. Then RGO/TiO₂ material was assembled into electrode, and NH₄⁺ ions electrosorption efficiencies of unmodified graphene (RGO) electrode and the RGO/TiO₂ electrode were compared. The effects of applied voltage, circulating velocity and initial concentration on NH₄⁺ ions electrosorption by RGO/TiO₂ electrode were investigated. The characteristics of NH₄⁺ ions electrosorption and the effect of advanced NH₄⁺ ions removal from simulated actual wastewater containing NH₄⁺ ions were also studied. The results showed that the RGO/TiO₂ composite material had a three-dimensional pore structure with specific surface area of 382.08 m²·g^-1 and specific capacitance of 325.80 F·g^-1 at a scan rate of 0.01 V·s^-1, which were better than those of the RGO material. The initial adsorption capacity of RGO/TiO₂ electrode was 28.3% higher than that of RGO electrode. After 10 cycles of regeneration adsorption, the adsorption capacity of NH₄⁺ ions of RGO/TiO₂ electrode only decreased 5.87%, and its cyclic regeneration adsorption property was better than that of RGO electrode. In addition, the applied voltage 2.0 V, circulating velocity 35 ml·min^-1 and initial concentration 1.0 mmol·L^-1 were the optimal NH₄⁺ ions electrosorption conditions for RGO/TiO₂ electrode. The electrosorption process of NH₄⁺ ions by RGO and RGO/TiO₂ electrodes was in accordance with the quasi-first-order kinetic model and the Freundlich isothermal adsorption model. The electrosorption of NH₄⁺ ions was a multi-layer adsorption behavior on heterogeneous surface and physical adsorption was the dominant. When the RGO/TiO₂ electrode was connected in 4-stage series, the removal efficiency of simulated actual NH₄⁺ refining purified water reached 86.84%.     

TiO2改性石墨烯电极电吸附去除污水中NH4+

通过水热法制备得到TiO₂改性石墨烯复合材料（RGO/TiO₂）,考察了其形貌结构和电化学性能。将其组装成电极,对比未改性石墨烯（RGO）电极和RGO/TiO₂电极的电吸附NH₄⁺性能。重点考察外加电压、循环流速、初始浓度等工艺参数对RGO/TiO₂电极电吸附NH₄⁺的影响,并对其电吸附NH₄⁺特性和对模拟实际含NH₄⁺废水深度脱NH₄⁺效果进行研究。结果表明：RGO/TiO₂复合材料具有三维孔洞结构,比表面积为382.08 m²·g^-1,比电容量在扫速为0.01 V·s^-1时达到325.80 F·g^-1,优于RGO材料。RGO/TiO₂电极的初次电吸附量较RGO电极提升了28.3%,循环再生吸附10次后,RGO/TiO₂电极的NH₄⁺吸附量仅降低了5.87%,循环再生吸附性能优于RGO电极。外加电压2.0 V、循环流速35 ml·min^-1和NH₄⁺初始浓度1.0 mmol·L^-1为RGO/TiO₂电极的最佳NH₄⁺电吸附条件。RGO和RGO/TiO₂电极电吸附NH₄⁺过程符合准一级动力学模型和Freundlich等温吸附模型,电吸附NH₄⁺为非均匀表面的多层吸附行为,以物理吸附为主。RGO/TiO₂电极4级串联时对模拟实际含NH₄⁺炼油净化水的去除率达到86.84%。     

Heterogeneous photocatalytic degradation of the cationic surfactant dodecylpyridinum chloride

The photodegradation has been studied of the cationic surfactant N-dodecylpyridinum chloride (N-DPCl) in aqueous heterogeneous dispersions of semiconducting catalyst particles (TiO₂, TiO₂/Pt and ZnO). The photooxidation was followed by UV spectrophotometry and surface tension measurements. The photodegradation approximates first order kinetics and is discussed on the basis of a simple phenomenological model. The degradation rate is almost identical for TiO₂ and ZnO and higher than that for TiO₂/Pt. A high mineralization yield is obtained from measurements of CO₂ evolution, while an increase in the surface tension is observed. Pyridinum ring breakage, which is known to proceed with difficulty, is also indicated by the presence of NH₄⁺ and NO₃⁻ ions.     

One step synthesis and characterization of copper doped sulfated titania and its enhanced photocatalytic activity in visible light by degradation of methyl orange

This paper reports on the synthesis of copper doped sulfated titania nano-crystalline powders with varying(2.0%–10.0%, by mass) by single step sol gel method. The synthesized photo catalyst has been characterized by employing various techniques like X-ray Diffraction(XRD), Ultraviolet–Visible Diffuse Reflection Spectroscopy(UV–Vis DRS), X-ray Photoelectron Spectroscopy(XPS), Scanning Electron Microscopy(SEM), Energy Dispersive Spectrometry(EDS), Fourier Transform Infrared Spectroscopic Studies(FT-IR), and Transmission Electron Microscopy(TEM). From the XRD and TEM results, all the samples were reported in anatase phase with reduction in particle size in the range of 7 to 12 nm. SEM indicated the change in morphology of the particles. The presence of copper in titania lattice was evidenced by XPS. From UV–Vis DRS and FT-IR studies indicated that prominent absorption shift is observed towards visible region(red shift), the entry of Cu2+into Ti O2 lattice as a substitutional dopant and SO42-ions were covalently bonded with Ti4 +on the surface of the copper doped titania respectively.The photocatalytic activity studies were investigated by considering methyl orange(MO) as dye pollutant in the presence of the visible light. The effect of various parameters like effect of dosage of the catalyst, dopant concentration, p H of the solution, and concentration of the dye was studied in detail.