MoP/TiO2-ZrO2催化剂制备及加氢脱氮性能考察

采用溶胶-凝胶法制备了TiO₂-ZrO₂复合载体,并用共浸渍法制备负载型MoP/TiO₂-ZrO₂催化剂,通过原位还原技术对催化剂进行还原处理后,在连续固定床反应器上进行活性评价。结果表明, TiO₂和ZrO₂物质的量比以及Mo负载量对催化剂活性有较大影响,当n(Ti)∶n(Zr)=4∶1和Mo负载质量分数为20%时,MoP/TiO₂-ZrO₂催化剂的加氢脱氮效果最好,并且TiO₂-ZrO₂复合载体比TiO₂-Al₂O₃复合载体的活性提高12.4个百分点。     

焙烧温度对TiO2成型载体性能的影响

以偏钛酸为原料,采用挤条成型的方法制备TiO₂成型载体。考察焙烧温度对TiO₂成型载体抗压强度、比表面积、孔容、孔径分布和晶相结构等的影响,采用XRD、BET、TG-DSC和SEM等手段对载体进行表征,并采用浸渍法制备了用于粗对苯二甲酸加氢精制的Pd/TiO₂催化剂。结果表明,提高焙烧温度有利于提高成型载体的侧压强度,但会使成型载体的比表面积和孔容降低,孔径分布向大孔方向位移。焙烧温度超过800 ℃,锐钛型TiO₂成型载体的晶型结构发生相变,逐步转变成金红石型。600 ℃制备的TiO₂成型载体的侧压强度在110 N·cm^－1以上,比表面积达60 m²·g^－1。并用TiO₂成型载体制备了质量分数0.5%Pd/TiO₂催化剂,用于对苯二甲酸加氢精制过程,4-CBA转化率达99%以上,为对苯二甲酸加氢精制催化剂研究提供了新的载体。酸     

TiO2复合氧化物的制备及其在加氢脱硫中的应用

对TiO₂、TiO₂-Al₂O₃、TiO₂-SiO₂和TiO₂-ZrO₂载体的制备技术及其在加氢脱硫中的应用进行了综述。研究表明，以TiO₂调变的Al₂O₃、SiO₂和ZrO₂载体能影响MoO₃与Al₂O₃、MoO₃与SiO₂及MoO₃与ZrO₂之间的相互作用，改善MoO₃在载体表面的分散，促进其还原，有利于提高催化剂表面活性组分的数量，提高催化剂的加氢脱硫活性。     

Zn2+离子掺杂对负载TiO2薄膜光催化活性的影响

以钛酸丁酯和ZnSO₄·7H₂O为原料，采用溶胶-凝胶法在钛片、玻璃、釉面瓷砖、陶瓷、不锈钢和铝片六种载体上制备了Zn²⁺掺杂TiO₂薄膜，讨论了不同Zn²⁺掺杂浓度下不同载体表面上制备的TiO₂薄膜对甲基橙脱色率的影响。结果表明，Zn²⁺对TiO₂薄膜的掺杂效果与载体的类型密切相关，并且不同载体其Zn²⁺掺杂的最佳浓度也不同。Zn²⁺掺杂后，TiO₂薄膜光催化活性提高最大的是釉面瓷砖，其次是钛片、玻璃、陶瓷。不锈钢和铝片上TiO₂薄膜的光催化活性不但没有升高，反而降低了。     

氨法选择性催化还原脱硝催化剂的研究

采用浸渍法,以TiO₂为载体,负载P₂ O₅、V₂O₅和MoO₃或WO₃制备选择性催化还原(SCR)催化剂,研究了不同磷含量以及水蒸汽对催化剂性能的影响。结果表明,随着催化剂中磷含量增加,P₂O₅-V₂O₅-MoO₃/TiO₂催化剂的SCR活性呈先上升后下降的趋势,其中,含质量分数0.5%P₂ O₅催化剂的活性较好。反应体系中水蒸汽的存在对催化剂的低温活性有明显的抑制作用。     

低含量Ni掺杂TiO2光催化剂及其在水溶液体系中的重复使用性能

利用溶胶-凝胶法制备了低含量Ni掺杂的TiO₂光催化剂粉体,考察了催化剂在甲基橙水溶液中的重复使用性能,并用XRD、XPS和N₂吸附-脱附等手段对催化剂进行了表征分析。结果表明,当掺杂Ni物质的量分数为0.3%和焙烧温度400 ℃时,制备的Ni/TiO₂的光催化降解甲基橙水溶液的活性高于纯TiO₂的光催化降解活性。Ni/TiO₂光催化剂在水溶液体系重复使用过程中,催化活性急剧下降,重复使用性能较差。Ni掺杂使TiO₂上产生具有较低结合能的低价钛离子如Ti^3＋,使表面缺陷（或氧空位）增加。比表面积和氧空位增加可能是Ni掺杂提高TiO₂光催化活性的主要原因。Ni流失可能是Ni/TiO₂在水溶液体系中重复使用性能较差的原因。     

不同载体表面负载TiO2薄膜的离子掺杂研究

TiO₂薄膜是解决TiO₂回收的有效方法，缺点是TiO₂活性低，寻找合适的载体以及提高TiO₂薄膜的光催化活性,是TiO₂负载薄膜技术需要解决的核心问题。研究了13种离子对负载在釉面瓷砖、玻璃、陶瓷、钛片、铝片和不锈钢片6种载体上TiO₂薄膜的掺杂，并从界面材料结构、双电层结构等方面讨论了离子掺杂与载体对TiO₂薄膜光催化活性的影响。结果表明，TiO₂薄膜的离子掺杂效果不仅和离子掺杂浓度、种类有关，而且还与载体类型有关。TiO₂薄膜和非金属载体主要形成复合半导体结构，改善掺杂离子对载流子的捕获能力。金属载体与TiO₂薄膜之间主要形成肖特基势垒，有利于电子与空穴的分离。载体与TiO₂薄膜之间形成的界面双电层结构能改变离子捕获中心与TiO₂半导体费米能级间的相对位置，从而提高或降低离子对载流子的捕获能力。     

TiO2-SiO2复合氧化物的理化性质及其对柴油加氢精制性能的影响

采用溶胶-凝胶法结合CO₂超临界流体干燥技术制备了不同Ti/Si原子比的TiO₂-SiO₂复合氧化物（TS-n）,考察了Ti/Si原子比、焙烧温度对复合氧化物比表面积、孔结构、酸性及原子结合状态的影响,通过重油催化裂化柴油加氢精制反应考察了以TS-1、TS-4为载体的催化剂脱硫性能的差异.结果表明,TiO2经SiO2复合改性后,热稳定性和晶态稳定性大幅度提高;TiO₂-SiO₂复合氧化物的酸性及原子间的相互作用与Ti/Si原子比有直接的关系;载体的晶态组成及酸性和催化剂的酸性对催化剂的加氢脱硫性能有显著影响,复合氧化物中锐态型TiO₂的存在强化了载体与金属组分之间的相互作用,提高了催化剂的加氢脱硫活性,不同类型的酸性中心对柴油中不同类型的硫化物具有不同的脱除能力,Bronsted 酸中心较多的催化剂对结构简单的硫化物脱除能力强,Lewis酸中心较多的催化剂对结构复杂的硫化物有较好的脱除效果.     

乙醇在SnO2掺杂的TiO2-Pt复合纳米催化剂上的电催化氧化

通过溶胶凝胶和电沉积法制备了SnO₂掺杂的钛基纳米TiO₂-Pt（nano-TiO₂-Pt）复合纳米催化剂。XRD和SEM的研究结果表明,SnO₂的掺杂改变了TiO₂的结构。通过对它们的电化学性质的比较发现,SnO₂的掺杂使nano-TiO₂-Pt复合纳米催化剂的电化学活性表面积增加,常温常压下对乙醇的电化学氧化电位负移,氧化能力明显提高。     

负载二氧化钛竹活性炭的制备及其性能的研究

以竹子为原料,通过磷酸活化法制备了一系列活性炭,考察其亚甲基蓝吸附值和焦糖脱色率,选择其中2项值都比较高的试样,通过溶胶-凝胶法制备负载型二氧化钛/竹活性炭光催化剂(TiO₂/BAC),并用其去除水溶液中的甲醛,以甲醛去除率为指标考察TiO₂/BAC的性能。结果表明,在浸渍比3:1,升温速率10℃/min,活化温度400℃,活化时间40min的工艺条件下得到的竹活性炭,比表面积大,大、中孔非常丰富。以上述条件下制得的活性炭所制备的TiO₂/BAC对水溶液中甲醛的去除效果非常明显:投加量为1.5g时,800mL初始浓度为5mg/L的甲醛水溶液,在17W紫外灯光照射的条件下,反应480min时甲醛去除率可达到84.28%。对比了单一TiO₂、单一竹活性炭、竹活性炭与TiO₂简单混合、TiO₂/BAC去除甲醛的效果,结果表明TiO₂/BAC去除甲醛的过程中,TiO₂与竹活性炭二者呈现明显的协同作用。     

Enhanced antibacterial activity of anodic aluminum oxide membranes embedded with nano-silver-titanium dioxide

In this work, the fabrication conditions of anodic aluminum oxide (AAO) templates with different pore size diameters were achieved using oxalic, tartaric, and phosphoric acidic electrolytes. Silver (Ag) nanostructures (NSs) were embedded in AAO template by simple hydrothermal and photoreduction methods. Moreover, titanium dioxide (TiO₂) NSs (nanowires) was deposited into these porous templates by sol-gel method. FESEM results suggested that Ag nanofishstars, nanonecklaces (NNs), and TiO₂ nanowires (NWs) like structures were grown in AAO pores with high-order and -aspect ratios. An anti-adhesive method was used to estimate the nano-size effect of the structures for enhancing antibacterial mechanism against Pseudomonas aeruginosa Gram-negative bacterium, and Staphylococcus aureus Gram-positive bacterium. In this study, the inhibition percentages of the Ag NNs/AAO membrane were 86.4, and 77.4%, respectively whereas that of the Ag film on glass substrate were 65, and 53.9%. Moreover, the inhibition percentages of the TiO₂ NWs/AAO membrane were 85.9, and 70.1%, on the other hand, the TiO₂ film on glass substrate were 60.3, and 45.2%. Results proved that the high porosity of the AAO template improved the contact-killing and release-killing actions of nanoparticles against biofilms.     

浆态光催化反应器有机模拟废水光催化氧化特性与动力学

采用循环式浆态光催化反应器对苯甲酰胺模拟废水光催化氧化特性和动力学进行了研究,系统地考察了操作条件对模拟污染物光催化降解的影响,并与搅拌式和鼓泡床式浆态光催化反应器中苯甲酰胺的降解效果进行对比.结果表明,循环式浆态光催化反应器中光催化剂的用量、污染物的初始浓度和初始pH值对模拟污染物光催化降解性能的影响存在适宜值;体系中H₂PO^-₄、Cl^-、Cu²⁺、Al³⁺对其光催化降解过程有明显的抑制作用.与传统的搅拌式和鼓泡床式浆态光催化反应器相比,循环式浆态光催化反应器中催化剂和废水的混合效果较好,光利用率高,较大程度上减少催化剂的用量和提高废水处理能力.同时,对不同催化剂的用量和污染物初始浓度下的光催化氧化反应动力学研究表明,此过程符合拟一级动力学,催化剂表面反应速率常数k₀和催化剂吸附平衡常数K_TiO2分别为0.0279 min^-1和17.99 L•g^-1.     

氧化亚铜纳米线的制备及其光电性能

摘要：通过电沉积法在阳极氧化铝模板中制备了Cu2O纳米线,利用X射线衍射(XRD)、扫描电子显微镜(SEM)对Cu2O纳米线的组成和形貌进行了表征,并测试了Cu2O/AAO阵列体系的光电压、交流阻抗性能。测试结果表明,制备的Cu2O纳米线的直径约120nm,长约2μm;Cu2O/AAO阵列体系在紫外灯(365nm)照射下,光电压约25mV, 阻抗值大大减小。     

TiO2光催化降解水中天然有机物富里酸的动力学模型

在天津地表水中天然有机物主要是富里酸,它是消毒副产物的主要前驱体,因此对于富里酸的控制非常重要.以粉末态TiO₂为催化剂,在光催化-超滤反应器中对水中天然有机物富里酸进行了光催化氧化研究,考察了富里酸氧化的主要影响因素,包括初始pH值、催化剂浓度、光强、添加剂浓度.结果表明：富里酸降解过程能够用一级反应动力学来表示;最佳的催化剂浓度为0.5 g•L^-1;在pH值减小、添加剂浓度和光强增大时有助于富里酸的去除.通过分析反应速率常数和影响因素之间的关系,得到富里酸光催化氧化总体动力学模型,试验值基本符合动力学模型.另外试验还表明该反应器可方便地实现有机物降解且具有较高的去除效率.     

Photocatalytic activity of TiO2-based materials for the oxidation of propene and benzene at low concentration in presence of humidity

This paper complements previous studies devoted to the photocatalytic oxidation of a low-concentration propene gaseous stream in absence of humidity using agglomerated TiO₂-based materials. These prepared agglomerated materials have shown very good oxidation activities and complete selectivity towards CO₂. The present paper analyses the role of humidity on propene oxidation, which has not been studied before, and extends the use of the prepared agglomerated photocatalysts to low concentration benzene oxidation, both in absence and presence of humidity. The obtained results have shown that humidity must be totally avoided, or kept as low as possible, to achieve high propene conversions. In the case of benzene, some insight to controversial published results is given; very low conversions together with benzene cracking on the surface of the photocatalyst occur in absence of humidity. However, the introduction of humidity leads to high conversions and avoids benzene cracking. The performance of the agglomerated photocatalyst containing a high surface area activated carbon (TiO₂/C1) must be underlined in terms of activity.     

TiO2纳米管的制备及对O3的催化性能

用水热法制备了高比表面积的TiO₂纳米管,通过TEM、XRD及BET进行物化表征,试验得到外径5～7 nm、壁厚1 nm左右、长200～300 nm、比表面积276 m²·g^-1的锐钛型TiO₂纳米管。试验考察了TiO₂纳米管的吸附性能及对O₃的催化性能和本征反应动力学,结果显示：60 min时O₃/UV/TiO₂纳米管较O₃/UV/P25和O₃/UV对垃圾渗滤液的COD去除率分别提高了20.83%和32.65%;293 K时0.5 g TiO₂纳米管对COD的最大吸附量为P25的1.34倍,对COD去除率贡献为10.14%; 2 h内O₃/UV/TiO₂纳米管工艺的总反应表观速率常数k分别是O₃/UV/P25工艺的1.19倍和O₃/UV工艺的1.80倍;得出两种催化工艺k-T关系方程,反应表观活化能E_a,nanotube比E_a,P25降低了2.925 kJ·mol^-1。     

Investigation into Photocatalytic Degradation of Gaseous Benzene in a Circulated Photocatalytic Reactor (CPCR)

Due to the fact that suspended TiO₂ powder enjoys free contact with gaseous pollutant molecules in photocatalytic reactors, it can generally achieve better efficiency than immobilized TiO₂ catalysts. However, difficulties with the separation of this catalyst powder from treated pollutants and its re‐use often limit its application. Therefore, a circulated photocatalytic reactor (CPCR) was designed to enhance the performance of the photocatalytic degradation of gaseous benzene. TiO₂ film photocatalysts were prepared by the sol‐gel method at low temperatures and coated onto the inner wall of this reactor by a bonding agent composed of poly‐(2, 2‐dimethyl)‐acrylic ethylene ester emulsion in which TiO₂ powder was characterized by FTIR, TEM and SEM. In particular, the influences of initial concentration and gas flow rate of benzene on the degradation conversion, D_p, apparent reaction rate constants, k_r, initial degradation rate, r, and the deactivation and regeneration of catalyst in the CPCR, were investigated. The results indicated that the degradation conversion, apparent reaction rate constants and initial degradation rate were closely correlated to the initial concentration of benzene. To elucidate the factors governing the observations, the adsorption characteristics and kinetics of the photocatalytic degradation of benzene were analyzed using the Langmuir adsorption isotherm and Langmuir‐Hinshelwood kinetic model. It was found that the reaction kinetics were best described by a fixed pseudo‐first‐order kinetic equation of photocatalytic degradation of gaseous benzene in the CPCR.     

Preparation and performances of mesoporous TiO2 film photocatalyst supported on stainless steel

Mesoporous TiO₂ film photocatalysts supported on stainless steel substrates were prepared using the sol–gel method with Ti(OC₄H₉)₄ as a precursor and poly ethylene glycol (PEG) as a structure-directing agent. Mesoporous TiO₂ film with a pore diameter of about 15 nm was obtained with the addition of PEG (molecular WEIGHT =400). The pore diameter of TiO₂film was varied with molecular weight of PEG additive. The structure-directing process was also discussed. Mesoscopically ordered inorganic/polymer composites were believed to form during the process. Compared to conventional TiO₂ film photocatalyst, the mesoporous TiO₂ film showed a good performance for the photo degradation of rhodamine B (RB) solution irradiated with UV light of 365 nm. The photo degradation constant of rhodamine B for mesoporous TiO₂ film photocatalyst can arrive at 22 times of that for conventional TiO₂ film photocatalyst. Also an excellent performance for the degradation of gaseous formaldehyde with mesoporous film photocatalyst was obtained. The photo degradation rate of gaseous formaldehyde for mesoporous TiO₂ film photocatalyst can arrive at six times of that for conventional TiO₂ film photocatalyst.     

Synthesis and characterisation of novel titania impregnated kaolinite nano-photocatalyst

Nano-sized titanium dioxide (TiO₂) has received a great attention in the field of research and development as a promising photocatalyst to promote the degradation of organic contaminants in water. One of the key technical challenges involved in separation and recovery of the photocatalyst particles from the water treatment system makes this technology unviable as an industrial process. A novel titania impregnated kaolinite (TiO₂/K) photocatalyst was synthesized by a modified two step sol–gel method: hydrolysis of titanium(IV) butoxide and heterocoagulation with pre-treated kaolinite (K) clay. The TiO₂/K photocatalysts were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and BET specific surface area measurements (BET). The photocatalytic activity was evaluated by the degradation of Congo red in aqueous solution. The TiO₂/K photocatalyst had a rigid porous layer structure and promising nano-size properties, and demonstrated an enhanced adsorption and photocatalytic ability for the removal of Congo red. The TiO₂/K photocatalyst can be easily separated and recovered from the water treatment system. The TiO₂/K photocatalyst is expected to deliver a true engineering solution for an industrial water/wastewater treatment process.     

Photocatalytic decomposition of 2-propanol in air by mechanical mixtures of TiO2 crystalline particles and silicalite adsorbent: The complete conversion of organic molecules strongly adsorbed within zeolitic channels

Fundamental photocatalytic behaviors were investigated for mechanical mixtures of TiO₂ crystalline particles (P25) and MFI type zeolite (silicalite) in the decomposition reaction of 2-propanol vapor in air for the first time. Mechanical mixing enables reliable comparisons to be made between photocatalysts because the contents of TiO₂ and the adsorbent can be widely varied (51 times in this study) while keeping the particle size and crystallinity of TiO₂ unchanged. That is, the use of mechanical mixture highlights the behavior of molecules adsorbed in the microporous crystals, keeping the TiO₂ unchanged. In the case of the mixed photocatalysts, the initial 2-propanol concentration in the gas phase was significantly reduced because of adsorption into the zeolite. After photo-irradiation started, 2-propanol was decomposed to CO₂ with no (or trace amount of) acetone detected in the gas phase. The analysis of final amount of CO₂ formed by the decomposition demonstrated that just by the mechanical mixing of TiO₂ and zeolite, the TiO₂ photocatalyst decomposed completely the reactant and intermediate molecules strongly adsorbed into the zeolite. On the other hand, in reference experiments in which TiO₂ and zeolite were not mixed and were separately placed in a photoreactor, the organic compounds strongly adsorbed in the zeolite could not be decomposed to CO₂ by the photocatalyst. It is notable that the CO₂ formation rates for the mixed photocatalysts were mostly constant for those comprising 40 wt% or larger amounts of zeolite, while being slower than for pure TiO₂. The rate-determining step was discussed based on these data. The present study showed that the mixed photocatalyst could remove organic vapors by adsorption in the dark and decompose completely to CO₂ at moderate reaction rates under photo-irradiation with minimized evolution of intermediate molecules into the gas phase.