SBA-15/Ni/TiO_2/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。     

镍基TiO2复合电极的制备及电催化析氢性能

在含有TiO₂颗粒的氨基磺酸体系镀镍液中通过电沉积制备了Ni/TiO₂复合镀层。采用扫描电子显微镜(SEM)、红外吸收光谱(FTIR)和X射线衍射(XRD)对镀层进行表征的结果显示,TiO₂颗粒成功地沉积在镍镀层中,并改变了镍镀层的表面微观形貌和相结构。通过极化曲线、塔菲尔曲线、电化学阻抗谱(EIS)、计时电位曲线等电化学测试考察了不同TiO₂质量浓度下所得Ni/TiO₂复合镀层的析氢活性和稳定性。与Ni镀层相比,Ni/TiO₂复合镀层显示出更高的析氢催化活性。TiO₂表面存在的羟基有利于析氢反应中氢吸附原子的形成,提高了析氢反应速率。在10 mA/cm²的阴极电流密度下,以6 g/L TiO₂制备的复合镀层表现出较低的析氢过电位(310 mV),具有最高的析氢活性。     

光催化剂对土壤中有机污染物的分解

研究掺杂型TiO₂光催化剂对土壤中有机污染物的分解效果及其催化剂的催化活性，考察不同金属离子掺杂型TiO₂光催化剂在土壤中加入量、光催化剂分散方式、光照时间、土壤的水分与厚度等因素的变化，通过超声萃取-高效液相色谱测定了光催化剂对有机污染物五氯酚的分解效果。结果显示，掺杂型TiO₂光催化剂的光催化活性不仅与自身对光的响应范围、吸收强度以及掺杂金属离子种类有关，还与晶体结构及分解的物质有关，表明光催化剂的催化活性是多方面因素共同作用的结果。     

活性炭纤维负载Pr3+:Y2SiO5/TiO2复合材料的制备与性能

为了提高纳米TiO₂对太阳光的利用率和实现光催化剂的回收再利用,采用溶胶-凝胶法将上转换荧光材料与纳米TiO₂复合,通过负载于活性炭纤维（ACF）表面制备了Pr³⁺：Y₂SiO₅/TiO₂/ACF复合材料。运用XRD、FT-IR、SEM、FS、UV-vis DRS等对材料的结构及性能进行了综合表征,并以亚甲基蓝为模拟污染物评价复合材料的可见光催化活性,考察了材料制备过程中煅烧温度、负载次数等制备条件对复合材料可见光下催化性能的影响。结果表明,在浸渍2次、800℃煅烧的制备条件下,复合材料中TiO₂为锐钛矿相（占34.1%）与金红石相（占65.9%）的混合相,亚甲基蓝（15 mg·L^-1）12 h内去除率高达93.8%,反应符合拟一级动力学,反应速率常数为0.2471 h^-1,回收再生利用4次后去除率仍保持在75%以上。     

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。     

CeO2-TiO2负载型复合光催化剂的制备和性能研究

以玻片为载体，采用溶胶-凝胶法制备了CeO₂-TiO₂复合光催化剂。采用XRD等对催化剂进行了表征。通过可溶性染料酸性媒介红B的微波辅助光催化氧化反应，考察了其光催化活性；并研究了复合催化剂的煅烧温度、铈掺杂量和涂覆次数等对催化活性的影响。实验结果表明，x（CeO₂）＝0.03％，涂覆次数为2次，在400 ℃焙烧2 ｈ的CeO₂-TiO₂负载型光催化剂的活性最高。     

CQDs/TiO2二元复合材料的制备及光催化性能研究

以柠檬酸、硫脲、尿素等廉价易得的药品为原料，采用水热法制备了3种不同荧光性能的碳量子点CQDs(绿色荧光碳量子点GCQDs、蓝色荧光碳量子点BCQDs、红色荧光碳量子点RCQDs)；同时采用溶胶-凝胶法制备了纳米TiO₂，然后通过物理法制备了3种二元复合光催化剂GCQDs/Ti O₂、BCQDs/TiO₂、RCQDs/TiO₂。采用FTIR、PL、XRD、BET等表征方法对产品进行了结构性能表征。通过紫外光谱分析，探究了Ti O₂和3种二元复合材料对次甲基蓝溶液的催化降解性能。光催化实验结果表明，纳米TiO₂在日光照射下10min对次甲基蓝的降解率为42.2%;GCQDs/TiO₂、BCQDs/TiO₂、RCQDs/TiO₂在日光照射下10min对次甲基蓝溶液的降解率分别为73.13%、46.82%、50.82%;3种二元复合材料的催化降解性能均优于纯TiO₂，其中GC...     

TiO2/Pt/玉米秸秆碳微球复合材料对光催化分解水制氢性能的影响

以玉米秸秆为原料，通过热熔法制备出TiO₂/Pt/玉米秸秆碳微球复合光催化剂。利用SEM、TEM、XRD、FT-IR、XPS、UV等方法对TiO₂/Pt/玉米秸秆碳微球进行表征。结果表明，TiO₂/Pt/玉米秸秆碳微球复合材料具有更高的光催化性能和光稳定性。在可见光照射、TiO₂/Pt与玉米秸秆碳微球质量比为1∶0.3时，光催化分解水制氢效率最高，达到1 120μmol/(h·g),是TiO₂/Pt制氢量的56倍。修饰在TiO₂上的玉米秸秆碳微球具有良好的导电性，可促进TiO₂光生电子的转移。同时，碳微球的加入增大了复合光催化剂的比表面积，提高了光催化制氢效率，为新型生物质光催化体系提供新思路。     

石墨烯/TiO2复合材料光催化降解有机污染物的研究进展

石墨烯是一种新型的碳纳米材料,具有超大的比表面积和优良的导电性能,将石墨烯与TiO₂复合可显著提高复合材料的光催化性能,在光催化领域具有广泛的应用前景。主要介绍了石墨烯/TiO₂复合纳米材料的制备方法以及在光催化降解有机污染物方面的应用,并分析了石墨烯/TiO₂复合材料促进光催化机理,最后对石墨烯/TiO₂复合光催化剂未来的发展趋势提出了展望。     

H3PW12O40/TiO2-SiO2光催化降解甲基红

采用溶胶-凝胶法制备TiO₂-SiO₂,用浸渍法将H₂PW₁₂O₄₀负载在TiO₂-SiO₂上,制得H₃PW₁₂O₄₀/TiO₂-SiO₂光催化剂。探究在模拟自然光条件下,光照时间、甲基红溶液初始浓度、催化剂用量和溶液pH对甲基红可见光催化降解的的影响。实验结果显示,在光照时间为15min.甲基红溶液初始浓度为15mg/L.催化剂用量为1.8g/L以及pH为2的优化条件下,甲基红的光降解率高达99.7%。光催化降解甲基红溶液为一级动力学反应。     

Role of the support on the activity of silica-supported TiO2 photocatalysts: Structure of the TiO2/SBA-15 photocatalysts

Immobilization of TiO₂ on silica materials has been commonly proposed in order to make easier the separation of the catalyst after the photocatalytic reactions in aqueous systems. The main drawback of the supported photocatalysts is that they usually show lower activities in comparison with powdered TiO₂ materials. The aim of this work is to elucidate the structure of some silica-supported TiO₂ photocatalysts recently developed as well as to evaluate the role that the porous structure of the support can play in the observed photocatalytic activities. In comparison with the use of an amorphous silica support, the use of the mesostructured silica SBA-15 produces an ordered structure in which TiO₂ crystals of similar sizes, independently of titania loading, are located inside the mesoporous channels of the support. The photocatalytic treatment of several cyanide-containing compounds is analyzed and the results are explained in terms of the structure of every catalyst. Depending on the model compound, the characteristic structure of the TiO₂/SBA-15 materials allows increasing up to eight times the activity achieved by the Degussa P25 TiO₂. The main conclusion of this work is the strong influence of the textural properties of the support on the catalytic activity of immobilized TiO₂ photocatalysts.     

The preparation of coupled WO3/TiO2 photocatalyst by ball milling

The coupled photocatalyst WO₃/TiO₂ is prepared by ball milling by doping WO₃ into TiO₂ and using H₂O solution as disperser. The coupled photocatalyst WO₃/TiO₂ is characterized by UV–VIS diffuse reflection spectrum, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Transmission electron microscopy (TEM). The results show that the optimum percentage of WO₃ doped is 3% and that the photocatalytic activity of the coupled WO₃/TiO₂ photocatalyst is much higher than that of TiO₂ and WO₃–TiO₂ with no ball milling. Compared with TiO₂, the photoexcited wavelength range of the WO₃/TiO₂ photocatalyst red-shifts about 50 nm, and the light absorption intensity is also improved. The crystal phase of TiO₂ is not changed and new crystal phases are not found during the process of ball milling. WO₃ and TiO₂ coupled highly, forming the WO₃/TiO₂ photocatalyst. The increased photocatalytic activity of the coupled photocatalyst may be attributed to the enhance charge separation efficiency and the extend wavelength range of photoexcitation.     

核壳结构镍基纳米催化剂的制备及其在肉桂醛加氢反应中的性能

分别以硝酸镍和氯化镍为镍源,利用热分解法和水合肼还原法制得镍纳米粒子,再经模板剂造孔法在镍核外部包裹一层介孔壳,通过焙烧和氢气还原制备了核壳结构催化剂Ni@mSiO₂和Ni-N₂H₄@mSiO₂,并以肉桂醛加氢为探针反应考察了核壳结构镍基催化剂与负载型镍基催化剂的加氢性能。结果表明,核壳结构镍基催化剂在肉桂醛加氢反应中比共沉淀法制备的负载型镍基催化剂具有更高的活性,氢化肉桂醛的收率可达90%以上。同时,Ni-N₂H₄@mSiO₂催化剂具有较高的磁饱和度,可实现该催化剂在反应后高效回收并循环套用。采用X射线衍射、比表面及孔分析、透射电子显微镜、H₂-程序升温还原和H₂-化学吸附等表征手段,研究了所制催化剂的结构特征,初步探讨了催化剂结构与性能的构效关系。     

铈硅包覆金红石型钛白粉及光催化性研究

采用溶胶-凝胶法,制备了铈硅包覆金红石型钛白粉,通过正交实验考察了浆液浓度、分散剂用量和两种包膜剂含量对铈硅包覆金红石型钛白粉性能的影响。采用Nano-ZS型粒度仪、扫描电镜（SEM）、透射电镜（TEM）和能谱（EDS）等测试手段,对金红石型钛白粉的Zeta电位、表面形貌和元素进行了表征。结果表明：在水浴温度为80 ℃左右、转速为600 r/min、浆液质量浓度为400 g/L、分散剂质量分数为0.1%、二氧化铈质量分数为3%、二氧化硅质量分数为4%的条件下,金红石型钛白粉表面包覆了两层均匀而致密的二氧化硅和二氧化铈膜;罗丹明B光催化降解实验证实,铈硅包覆明显改善了金红石型钛白粉的光催化屏蔽性。     

Effects of hydrothermal temperature and time on the photocatalytic activity and microstructures of bimodal mesoporous TiO2 powders

Bimodal nanocrystalline mesoporous TiO₂ powders with high photocatalytic activity were prepared by a hydrothermal method using tetrabutylorthotitanate (TiO(C₄H₉)₄, TBOT) as precursor. The as-prepared TiO₂ powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and N₂ adsorption–desorption measurements. The photocatalytic activity of the as-prepared TiO₂ powders was evaluated by the photocatalytic degradation of acetone (CH₃COCH₃) under UV-light irradiation at room temperature in air. The effects of hydrothermal temperature and time on the microstructures and photocatalytic activity of the TiO₂ powders were investigated and discussed. It was found that hydrothermal treatment enhanced the phase transformation of the TiO₂ powders from amorphous to anatase and crystallization of anatase. All TiO₂ powders after hydrothermal treatment showed bimodal pore-size distributions in the mesoporous region: one was intra-aggregated pores with maximum pore diameters of ca. 4–8 nm and the other with inter-aggregated pores with maximum pore diameters of ca. 45–50 nm. With increasing hydrothermal temperature and time, the average crystallite size and average pore size increased, in contrast, the Brunauer-Emmett-Teller (BET) specific surface areas, pore volumes and porosity steadily decreased. An optimal hydrothermal condition (180 °C for 10 h) was determined. The photocatalytic activity of the prepared TiO₂ powders under optimal hydrothermal conditions was more than three times higher than that of Degussa P25.     

CNTs/Ta3N5 Nanocomposite with Enhanced Photocatalytic Activity Under Visible Light Irradiation

Carbon nanotubes (CNTs)/Ta₃N₅ nanocomposite is presented as a novel photocatalyst working under visible light irradiation. The results of Fourier transform infrared analyses and transmission electron microscopy indicate that a good interfacial combination has formed between CNTs and Ta₃N₅ nanoparticles. The CNTs/Ta₃N₅ nanocomposite shows strong absorption in the visible light range compared with pure Ta₃N₅ and has a bandgap energy of 2.01 eV. The photocatalytic experiments show that the nanocomposite has a higher photocatalytic activity than Ta₃N₅ nanoparticles.     

Effect of external bias voltage and coating thickness on the photocatalytic activity of thermal sprayed TiO2 coating

TiO₂ coatings of different thickness were prepared by a thermal spray process. It was found that the external bias applied to the as-sprayed TiO₂ coating could significantly improve its photocatalytic performance, which was characterized by decomposition of methylene blue (MB) solution. The decomposition efficiency increased with increasing external bias voltage. However, for voltage greater than 15 V, the decomposition efficiency remained constant. The TiO₂ coating with a thickness of 6 μm showed the best photocatalytic performance under an external bias voltage of 15 V.     

Hydrothermal doping method for preparation of Cr-TiO2 photocatalysts with concentration gradient distribution of Cr

Cr³⁺-doped anatase titanium dioxide photocatalysts were prepared by the combination of sol–gel process with hydrothermal treatment. The samples were characterized by UV–vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area (S_BET), transmission electron microscopy (TEM), atomic absorption flame emission spectroscopy (AAS), electron paramagnetic resonance (EPR) spectroscopy and X-ray photoelectron spectroscopy (XPS). It was confirmed that Cr substitutes Ti⁴⁺ in TiO₂ lattice in trivalent ionic state, and the concentrations of dopants Cr³⁺ decrease from the exterior to the interior of doped TiO₂. The photocatalytic activity of Cr-TiO₂ was investigated for the photocatalytic degradation of XRG aqueous solution both under UV and visible light irradiation. Due to the excitation of 3d electron of Cr³⁺ to the conduction band of TiO₂, Cr-TiO₂ shows a good ability for absorbing the visible light to degrade XRG. Doping of chromium ions effectively improves the photocatalytic activity under both UV light irradiation and visible light irradiation with an optimal doping concentration of 0.15% and 0.2%, respectively. The special distribution of dopants Cr³⁺ seems having a good effect on enhancing the photocatalytic activity of Cr-TiO₂.     

SBA-15 supports modified by Ti and Zr grafting for NiMo hydrodesulfurization catalysts

A series of Ti- and Zr-containing mesoporous SBA-15 supports and their respective NiMo catalysts were prepared to study the effect of the Ti and Zr loading into the support on the characteristics of Ni and Mo surface species and their catalytic activity in the 4,6-dimethyldibenzothiophene hydrodesulfurization (HDS). Ti and Zr-containing SBA-15 solids with different metal loading (up to 19 wt.% of TiO₂ or 22 wt.% of ZrO₂) were prepared by chemical grafting. The solids prepared were characterized by N₂ physisorption, X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (DRS), temperature-programmed reduction (TPR), chemical analysis and HRTEM. The results show that Ti- and Zr-SBA-15 supports with highly dispersed Ti and Zr species can be obtained without substantial loss of SBA-15 characteristics. Zr grafted species showed somewhat better dispersion on the SBA-15 surface than the corresponding Ti counterparts. It was found that TiO₂ and, especially, ZrO₂ incorporation in the SBA-15 support leads to stronger interaction of Mo and Ni species with the support providing better dispersion to the oxidic and sulfided metal species (XRD, TPR, HRTEM). NiMo catalysts supported on Ti- and Zr-containing SBA-15 showed high activity in 4,6-dimethyldibenzothiophene HDS. It can be concluded therefore that SBA-15 materials grafted with Ti or Zr species show promising features as supports for Mo-based hydrotreating catalysts.     

A chemical etching route to controllable fabrication of TiO2 hollow nanospheres for enhancing their photocatalytic activity

The TiO₂ hollow nanospheres with diameters of about 230 nm were prepared by a simple and controllable route based on hydrolysis of Ti(OBu)₄ on the surfaces of the Cu₂O solid nanospheres followed by inward etching of the Cu₂O nanospheres. The as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The further post-heat treatment led to the high crystallization of the TiO₂ hollow nanospheres. The photocatalytic performances of these samples were evaluated for the photodegradation of rhodamine B (RhB) under UV-light irradiation. The as-prepared TiO₂ hollow nanospheres showed higher photocatalytic activity than the CuO and the CuO/TiO₂ hollow nanospheres. Effects of temperature and time for post-heat treatment of TiO₂ as well as initial RhB concentrations on the RhB photodegradation have also been studied. The results show that the TiO₂ hollow nanospheres have the good reusability as photocatalysts and are promising in waste water treatment.