High photocatalytic activity and stability for decomposition of gaseous acetaldehyde on TiO2/Al2O3 composite films coated on foam nickel substrates by sol-gel processes

A set of anatase titanium dioxide (TiO₂) films coated on foam nickel that modified by Al₂O₃ films as transition layer (indicated as TiO₂/Al₂O₃ films) were synthesized via sol-gel route. The bulk and surface properties of the TiO₂/Al₂O₃ films were characterized by thermal gravimetric and differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), and BET. The photocatalytic activities of TiO₂/Al₂O₃ films were investigated based on the degradation of gaseous acetaldehyde under ultraviolet (UV) irradiation. The foam nickel is a promising substrate material in practical applications because of its excellent hydrodynamic properties for gas passing. The TiO₂/Al₂O₃ composite films showed much higher photocatalytic activity and stability for degradation of gaseous acetaldehyde than the onefold TiO₂ films. The significant enhancement in photocatalytic activity and stability can be ascribed to the coating of Al₂O₃ transition layer, which concentrates the target substances around TiO₂ particles and increases the specific surface area (SSA) of the substrate (the SSAs of bare foam nickel and Al₂O₃ modified foam nickel are 0.12 and 113.7 m²/g, respectively) to provide more sites for TiO₂ loading.     

偏硼酸锶/碳酸锶复合催化剂光催化还原CO2生成CH4的研究

采用溶胶-凝胶法制备出SrB₂O₄和SrCO₃复合催化剂(SrB₂O₄/SrCO₃). 紫外光催化还原CO₂生成CH₄的实验证明, SrB₂O₄/SrCO₃复合催化剂的光催化活性已超过SrB₂O₄和TiO₂(P25)催化剂. 利用X 射线电子衍射(XRD)谱、透射电子显微镜(TEM)和等温氮气吸附-脱附分析确定了催化剂的晶相结构、粒子尺寸和比表面积.利用紫外-可见(UV-Vis)漫反射吸收光谱、X射线光电子能谱(XPS)的价带谱和荧光光谱(PL)确定了催化剂的能带结构, 结果表明: SrB₂O₄/SrCO₃复合催化剂异质结构有利于光生载流子的分离, 从而抑制了光生电子和光生空穴的复合, 提高了光生电子和光生空穴在固液界面参加光催化反应的利用率. 因此, SrB₂O₄/SrCO₃复合催化剂的紫外光催化活性得到了有效的提高.     

Photocatalytic Degradation of Organic Reactive Dyes over MnTiO3/TiO2 Heterojunction Composites Under UV‐Visible Irradiation

In this study, the photocatalytic degradation of organic reactive dyes have been investigated using MnTiO₃/TiO₂ heterojunction composites in the presence of electron acceptors under UV‐Visible light irradiation. This MnTiO₃/TiO₂ heterojunction composites were prepared by annealing different mass ratios of pyrophanite MnTiO₃ (3–11 wt%) and TiO₂ at 300°C. All the MnTiO₃/TiO₂ heterojunction composites were characterized by spectral techniques like X‐ray diffraction (XRD), scanning electron microscope (SEM) and diffused reflectance UV‐visible spectroscopic analysis (DRS). Among them, 9 wt% MnTiO₃/TiO₂ heterojunction composites exhibited higher photocatalytic activity for the degradation of Reactive Blue 4 (RB 4). The photocatalytic efficiency of 9 wt% MnTiO₃/TiO₂ heterojunction composites was further enhanced by the addition of substantial amount of electron acceptors like hydrogen peroxide (H₂O₂) and ammonium peroxydisulfate ([NH₄]₂S₂O₈). The presence of oxidants (electron acceptors) facilitates the fast degradation of dye solution even in higher concentration upto 200 mg/L. The photocatalytic activity of MnTiO₃/TiO₂ heterojunction composites was also studied for the degradation of other four different structured reactive dyes. The extent of mineralization of these organic reactive dyes during photocatalytic degradation was estimated from COD analysis. MnTiO₃/TiO₂ heterojunction composites was also found to have good photostability in the presence of oxidants.     

Physical properties of nano-titania hollow fibers and their photocatalytic activity in the decomposition of phenol

A series of nano-titania (TiO₂) photocatalytic materials with a hollow fiber structure were successfully prepared using tetra-n-butyl titanate (Ti(OC₄H₉)₄) as precursor and cotton fiber as the template. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and N₂ adsorption-desorption measurements were employed to characterize the morphology, crystal structure, and surface structure of the samples. The photocatalytic activities of the samples were studied by phenol photodegradation in water under UV irradiation. The effect of calcination temperature, photocatalyst dosage, initial concentration of phenol and irradiation time on the photodegradation of phenol was studied. Results showed that the TiO₂ fiber materials have hollow structures, indicating that these materials had a large specific surface area. The fiber structure material showed better photocatalytic properties for the degradation of phenol than pure TiO₂ under UV light, and the sample calcined at 500°C exhibited the highest phenol photodegradation efficiency. In addition, the possibility of cyclic usage of the photocatalyst was also confirmed, the photocatalytic activity of TiO₂ fiber remained ca. 90% of photocatalytic activity of the fresh sample after being used four times. Moreover, TiO₂ fiber was easily recovered by centrifugal separation from water.     

Investigations on the Phase Transformation,Optical Characteristics,and Photocatalytic Activity of Synthesized Heterostructured Nanoporous Bi2O3–TiO2

Fine‐powdered, heterostructured, nanoporous Bi₂O₃–TiO₂ (BTO) was synthesized by a green approach using ultrasonication, with the mole ratio Bi/Ti of 1:1 and calcined at different temperatures. The physical and optical properties of the mixed oxides were investigated. The phase structure, as identified by X‐ray diffraction (XRD), showed the appearance of new phases as a function of the calcination temperature. Morphological examinations indicated the formation of a nanoporous structure with a drastic change in morphology at the calcination temperature of 850°C from a globule to a rod‐shaped structure, which further got transformed to a rocky appearance at 1200°C. Doping with Bi₂O₃ led to the lowering of the bandgap of TiO₂ from 3.25 to 2.5 eV. A BTO nanocatalyst calcined at 450°C exhibited promising photocatalytic activity for the degradation of quinalphos (QP) (92%) after a time interval of 100 min under visible light and at the optimum pH 8. The kinetics of degradation of QP showed that it follows a pseudo‐first‐order path with a rate constant 0.01267 min^?1. The synthesized BTO mixed oxide showed profound improvement in photocatalytic activity in the visible region as compared to TiO₂.     

Semiconductor‐photocatalyzed degradation of carboxylic acids: Enhancement by particulate semiconductor mixture

Degradation of oxalic acid on particulate TiO₂, ZnO, CuO, Bi₂O₃, In₂O₃, and Nb₂O₅ under UV‐A light exhibits first‐order kinetics, and the degradation rates increase linearly with the photon flux. All the oxides show sustainable photocatalytic activity, and the photonic efficiencies of degradation of oxalate are very much lower than those of the acid. The ease of degradation of carboxylic acids is the following: formic > oxalic > acetic > citric. Intimate mixtures of two different particulate semiconductors kept under suspension and at continuous motion exhibit higher photocatalytic activity, revealing interparticle charge transfer. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 716–726, 2009     

Photocatalytic Activity of Fibrous Ti/Ce Oxides Obtained by Hydrothermal Impregnation of Short Flax Fibers

Fibrous Ti/Ce oxide photocatalysts were prepared for the first time by a biomimetic solution process using short flax fibers (flax straw processing waste) as a biotemplate. Titanium polyhydroxy complex solutions with 3% and 5% cerium were used as precursors. Flax fibers were impregnated in an autoclave under hydrothermal conditions. Ti/Ce oxides were obtained from the biotemplate by annealing at 600 °C. The photocatalytic activity of the Ti/Ce oxides was studied by the adsorption and decomposition of the dye rhodamine B under UV irradiation. The photocatalytic decomposition of the dye was 50% and 75% faster for Ti/Ce oxides with 3% and 5% Ce, respectively, than for the analogous undoped fibrous TiO₂. The morphologies, textures, and structures of the photocatalysts were studied by scanning electron microscopy, low temperature N₂ adsorption/desorption, UV-Vis spectroscopy, and X-ray and XPS analytical methods. It was shown that the introduction of Ce into the precursor solution increased the surface irregularity of the Ti/Ce oxide crystallites compared to pure TiO₂. This effect scaled with the Ce concentration. Ce improved the UV light absorption of the material. The Ti/Ce oxides contained Ce⁴⁺/Ce³⁺ pairs that played an important role in redox processes and intensified the photocatalytic activity.     

Preparation of Er3+:Y3Al5O12/TiO2 composite film and influence of layer number and layer sequence on the visible-light photocatalytic activity

In this work, the Er³⁺:Y₃Al₅O₁₂ as up-conversion luminescence agent was mixed with TiO₂ and the corresponding Er³⁺:Y₃Al₅O₁₂/TiO₂ composite films were prepared on the one-sided surface of treated sheet glass through sol-gel dip-coating method. The prepared Er³⁺:Y₃Al₅O₁₂/TiO₂ composite films were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Their photocatalytic activities were examined through the degradation of some organic dyes under visible-light irradiation. The degradation process of organic dyes was monitored by UV-Vis spectrophotometer. Furthermore, some main influence factors on the visible-light photocatalytic activity of Er³⁺:Y₃Al₅O₁₂/TiO₂ composite film such as heat-treatment temperature and heat-treatment time were studied. The results indicate that three layer Er³⁺:Y₃Al₅O₁₂/TiO₂ composite films with one Er³⁺:Y₃Al₅O₁₂/TiO₂ composite film (as first layer close to sheet glass) and two pure TiO₂ film (as second and third layers) display a higher visible-light photocatalytic activity during photocatalytic degradation of Azo Fuchsine. In addition, the results showed that the visible-light photocatalytic activity of Er³⁺:Y₃Al₅O₁₂/TiO₂ composite film related to the layer number and layer sequence on the sheet glass. Perhaps, the research results may offer some meaningful references for developing solar energy continuous flow wastewater treatment reactor.     

Preparation of ZnFe<Subscript>2</Subscript>O<Subscript>4</Subscript> nanoparticles by mechanical alloying and annealing for sensitizing C-modified TiO<Subscript>2</Subscript> and acquirement of efficient photocatalyst

ZnFe₂O₄ nanoparticles sensitized by C-modified TiO₂ hybrids (ZnFe₂O₄–TiO₂/C) were successfully prepared by a feasible method. The ZnFe₂O₄ nanoparticles were prepared by mechanical alloying and annealing. The residual organic compounds in the synthetic process of TiO₂ were selected as the carbon source. The as-prepared composites were characterized by X-ray diffraction, Raman spectroscopy, X-ray fluorescence, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible light diffuse reflectance spectroscopy (UV–Vis) and N₂ adsorption–desorption analysis. The photocatalytic activity of the photocatalysts was measured by degradation of methyl orange under ultraviolet (UV) light and simulated solar irradiation, respectively. The results show that the carbon did not enter the TiO₂ lattice but adhered to the surface of TiO₂. The photocatalytic activity of the as-prepared C-modified TiO₂ (TiO₂/C) improved both under UV and simulated solar light irradiation, but the improvement was not dramatic. Introduction of ZnFe₂O₄ into the TiO₂/C could enhance the absorption spectrum range. The ZnFe₂O₄–TiO₂/C hybrids exhibited a higher photocatalytic activity both than that of the pure TiO₂ and TiO₂/C under either UV or simulated solar light irradiation. The complex synergistic effect plays an important role in improving the photocatalytic performance of ZnFe₂O₄–TiO₂/C composites. The optimum photocatalytic performance was obtained from the ZnFe₂O₄(0.8 wt%)–TiO₂/C sample.     

微波辅助溶剂热合成In-Si共改性TiO2的增强光催化性能

利用微波辅助溶剂热法合成了In-Si 共改性的TiO₂ 光催化剂. 粉末X 射线衍射（XRD）、激光拉曼（Raman）光谱、N₂吸脱附（BET）、X射线光电子能谱（XPS）、光致发光（PL）光谱和紫外-可见漫反射光谱（UV-VisDRS）等实验表明,尽管掺杂和改性后TiO₂结晶度略有降低,但不影响光催化剂锐钛相的形成. Si 掺杂入TiO₂晶格使颗粒变小,比表面积变大. In 不能进入TiO₂晶格,在TiO₂表面形成了In₂O₃. 罗丹明B（RhB）降解实验显示,In-Si 共改性TiO₂表现出很高的紫外和可见光催化活性,Si：In：Ti 的摩尔比为0.03：0.02：1 的样品（IST-2）光催化活性最高,紫外光下3 min 即可将RhB降解完全,可见光下120 min RhB降解率为97%,这是由材料的高表面积,In₂O₃-TiO₂复合半导体之间高效电荷转移及染料敏化等共同作用所致. 对于苯酚,光催化降解则相对缓慢,700 min内尚不能降解完全.     

三维有序大孔复合材料Bi2O3/TiO2制备与多模式下光催化降解结晶紫

以TiO2为基体,在聚苯乙烯(PS)胶球和EO20PO70EO20(P123)两种模板剂作用下通过溶胶-凝胶及煅烧后处理方法制备了三维有序大孔纳米复合材料Bi2O3/TiO2.经傅里叶变换红外(FT-IR)光谱、X-射线衍射(XRD)、等离子体原子发射光谱(ICP-AES)、紫外-可见漫反射吸收光谱(UV-Vis DRS)、X-射线光电子能谱(XPS)、扫描电子显微镜(SEM)和N2吸附-脱附等物理测试手段对其组成、结构、形貌及表面物理化学性能进行了表征.结果表明,该复合材料晶型结构良好,孔结构排列整齐有序,孔壁呈介孔结构,属于三维有序大孔材料(3DOM).与TiO2相比,3DOM-Bi2O3/TiO2对光的吸收至少红移60 nm,且红移至可见区.在紫外光、可见光以及微波辅助等多模式光催化降解结晶紫的实验中,复合材料3DOM-Bi2O3/TiO2表现出良好的光催化活性,其活性明显高于P25、Bi2O3和Bi2O3/TiO2.同时,该复合材料针对不同类型的染料均表现出较好的紫外光降解效果,且3次循环实验后,依旧保持较高活性.     

钛铁矿制备二氧化钛-四氧化三铁复合材料及其光催化应用

TiO_2因具有多种优异的特性被广泛应用在半导体光催化领域,但是纳米结构的TiO_2颗粒细微,在进行光催化反应之后,难以回收再利用。本文以廉价钛铁矿为原料制备光催化剂TiO_2,同时利用副产物铁合成Fe_3O_4,并采用简单温和的浸渍法制备Fe_3O_4/TiO_2磁性复合材料。通过XRD、FT-IR、SEM、EDS等手段对材料形态结构进行表征分析,并以光降解有机污染物若丹明B为探针反应,考察其光催化性能。结果表明,质量比为1∶10的Fe_3O_4/TiO_2复合材料结构稳定、分散均匀,具有最优的光催化活性(波长356nm下反应3h,若丹明B降解率达到64.0%),并表现出良好的重复性。同时,动力学结果显示降解符合一级反应动力学。     

Elaboration of nano titania-magnetic reduced graphene oxide for degradation of tartrazine dye in aqueous solution

In this paper, magnetic nanocomposites are synthesized by loading reduced graphene oxide (RG) with two components of nanoparticles consisting of titanium dioxide (TiO₂) and magnetite (Fe₃O₄) with varying amounts. The structural and magnetic features of the prepared composite photocatalysts were investigated by powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (UV–vis/DRS), Raman and vibrating sample magnetometer (VSM). The resulting TiO₂/magnetite reduced graphene oxide (MRGT) composite demonstrated intrinsic visible light photocatalytic activity, on degradation of tartrazine (TZ) dye from a synthetic aqueous solution. Specifically, it exhibits higher photocatalytic activity than magnetite reduced graphene oxide (MRG) and TiO₂ nanoparticles. The photocatalytic degradation of TZ dye when using MRG and TiO₂ for 3 h under visible light was 35% and 10% respectively, whereas for MRGT it was more than 95%. The higher photocatalytic efficiency of MRGT is due to the existence of reduced graphene oxide and magnetite which enhances the photocatalytic efficiency of the composite in visible light towards the degradation of harmful soluble azo dye (tartrazine).     

Rapid Synthesis of Nanocrystalline TiO2/SnO2 Binary Oxides and Their Photoinduced Decomposition of Methyl Orange

A rapid and simple method, the so-called stearic acid method (SAM) was developed to prepare nanostructured TiO₂/SnO₂ binary oxides by combustion of stearic acid precursors. The preparative process was studied by Fourier transform infrared spectroscopy (FT-IR). During the preparative process, metal precursors were dispersed in stearic acid at molecular level. Microstructure of the samples was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), BET specific surface area measurement and the results were compared with those obtained by conventional sol-gel method. The photocatalytic decomposition of methyl orange was used as a model system to determine the relative influences of the preparation method and the concentration of SnO₂ on the photocatalytic activities. It was found that preparative methods affected the crystalline structure of TiO₂/SnO₂ powders and the anatase phase of TiO₂ was stabilized by the addition of SnO₂ in SAM. The samples prepared by SAM showed better dispersity, larger specific surface area and the TiO₂/SnO₂ (r=0.15, SAM) catalyst showed higher photocatalytic activity than Degussa P25.     

Preparation of CdS–TiO2/Fe3O4 photocatalyst and its photocatalytic properties

The CdS modified TiO₂/Fe₃O₄ photocatalysts were prepared by sol–gel and immersion methods. The morphological, structural and optical properties of as-prepared samples were characterized by X-ray diffraction (XRD), UV–Vis absorption spectra, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The TEM observation showed that the surface of magnetite particles (Fe₃O₄) were coated by CdS–TiO₂ layer as loose clusters, and average diameter of composites particles was about 250 nm. UV–Vis absorption spectra indicated that CdS–TiO₂/Fe₃O₄ composites had pronounced red-shift compared with that of TiO₂/Fe₃O₄. The CdS–TiO₂/Fe₃O₄ composites exhibit higher photocatalytic activity than pure TiO₂ and TiO₂/Fe₃O₄ for the degradation of Reactive Brilliant Red X-3B dye (X-3B) aqueous solution under simulated sunlight, and the optimum content of CdS is 1.0 % (mol ratio of CdS to TiO₂). In addition, a gradual loss of photocatalytic activity can be observed in reusability test of CdS–TiO₂/Fe₃O₄ composites, and degradation of X-3B reached still to 78.9 % after five runs.     

具有分级多孔结构和光催化性质的核-壳纳米球(HP-Fe2O3@TiO2)

通过溶剂热和溶胶-凝胶涂层法, 设计并制备了具有分级多孔结构和光催化性质的核-壳纳米球(HP-Fe₂O₃@TiO₂). 透射电子显微镜(TEM)照片证明所得HP-Fe₂O₃@TiO₂样品具备分级多孔结构, 这是因为HP-Fe₂O₃@TiO₂的内核-Fe₂O₃具有大孔空隙, 同时外壳-TiO₂具有介孔空隙. 此外, 通过X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、X射线光电子能谱(XPS)以及氮气吸附-脱附曲线深入研究了HP-Fe₂O₃@TiO₂的结构及其性质. 分别在可见及紫外光照下, 研究了样品在H₂O₂体系下的光催化降解亚甲基蓝(MB)的性质. 所观察到的HP-Fe₂O₃@TiO₂纳米球的光催化性能, 可归因于核-壳结构的协同作用, 这进一步表明, TiO₂外壳对α-Fe₂O₃的光催化活性有重要影响作用. 在可见光照射下, HP-Fe₂O₃@TiO₂ (1 mL Ti(OC₄H₉)₄ (TBT))具有较优异的光催化活性. 同时, HP-Fe₂O₃@TiO₂ (4mL TBT)具备优异的单分散形貌, 并在紫外光照射下, 表现出最优的光催化活性.     

Significant effect of lanthanide doping on the texture and properties of nanocrystalline mesoporous TiO2

A systematic study of microstructure and photocatalytic properties of lanthanide doping of nanocrystalline mesoporous titanium dioxide is performed. The anatase-to-rutile (A-R) phase transformation of nanosized TiO₂ was significantly inhibited by lanthanide doping and the inhibitory effect was enhanced with the increase of the rare earth radius, i.e., La³⁺>Gd³⁺>Yb³⁺ for different lanthanide dopants. At high calcination temperatures, different texture lanthanide titanium oxides of Ln₄Ti₉O₂₄ (La³⁺, Pr³⁺, Nd³⁺), Ln₂Ti₂O₇ (Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Er³⁺), and Yb₂TiO₅ were developed, respectively, revealing that the structures of lanthanide titanium oxide developed in Ln/TiO₂ depend on the lanthanide radius. Larger radius lanthanides prefer to form higher coordination number lanthanide titanium oxide. In addition, the thermal stability of mesoporous structures of TiO₂ was remarkable improved by lanthanide doping. The photocatalytic properties were studied by employing the photodegradation of Rhodamine B (RB) as a probe reaction. The results indicate that the lanthanide doping could bring about significant improvement to the photoreactivity of TiO₂, and the improvement was sensitive to the atomic electronic configuration.     

Influence of titanium oxide on the surface interactions of MO (M=Cu and Ni)/γ-Al2O3 catalysts

The influence of titanium oxide on the surface interactions of MO (M=Cu and Ni)/γ-Al₂O₃ catalysts has been studied by using XRD, LRS and XPS. For the catalysts with titania loadings lower than 0.56 mmol Ti⁴⁺/100 m² Al₂O₃ (i.e., the dispersion capacity), the dispersion of MO oxides on the surface of γ-Al₂O₃ support is significantly suppressed by the dispersed Ti⁴⁺ ions. The inhibiting effect is dependent on the properties of MO oxides. When titania loadings are considerably higher than the dispersion capacity, MO oxides exhibit a rather stronger interaction with the formed TiO₂ particles than the γ-Al₂O₃ support, and some of the dispersed M²⁺ ions might be accommodated by the vacant sites on TiO₂. Therefore, the catalysts can be considered as the compositions of MO/TiO₂ and MO/TiO₂/γ-Al₂O₃ (dispersed titania). TPR results show that either dispersed titania or formed TiO₂ particles can promote the reduction of copper oxide species, but the latter to a greater extent. Based on the consideration of the incorporation model, it is proposed that the surface structure of the support plays an important role in surface interactions.     

花状TiO2分级结构的可控合成与其光催化性能

采用水热法可控合成了花状TiO₂分级结构材料,运用扫描电镜、透射电镜、X射线衍射、N₂物理吸附-脱附等手段,对其进行了表征,系统研究了NaOH用量、H₂O₂浓度、HNO₃浓度、反应温度及时间等因素对所得样品形貌的影响,并评价了它们的光催化性能.结果表明,花状TiO₂分级结构为锐钛矿相,颗粒大小均一;随制备条件的变化,构成花状TiO₂分级结构的基元结构分别为纳米线、纳米片,纳米线直径约25nm,纳米片厚度不足10nm;该样品具有较高的比表面积,表现出良好的单次光催化活性与重复使用性能.     

Photocatalytic degradation of organophosphate flame retardant TBEP: kinetics and identification of transformation products by orbitrap mass spectrometry

The photocatalytic degradation of tris (2–butoxyethyl) phosphate (TBEP) flame retardant using visible light response catalysts TiO₂/V₂O₅, (N,F-doped)-TiO₂/V₂O₅, and N-doped-SrTiO₃ has been studied by high-resolution orbitrap mass spectrometry. TBEP degradation followed first-order kinetics with half-life values ranging between 9.8 and 83.5 min. N-doped-SrTiO₃ was the catalyst with better photocatalytic performance while activity for TiO₂/V₂O₅ composites followed the trend: N, F- TiO₂/V₂O₅ > N-TiO₂/V₂O₅> TiO₂/V₂O₅. The identified degradation products (DPs) revealed hydroxylation, further oxidation and dealkylation as major degradation pathways. Based on the identified DPs and scavenging experiments, ^?OH radical-mediated reactions can be considered for the degradation of TBEP using TiO₂ and SrTiO₃-based photocatalytic materials.