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A Photoresponsive Rutile TiO <sub/>2</sub> Heterojunction with Enhanced Electron-Hole Separation for High-Performance Hydrogen Evolution
摘要： Rutile titanium dioxide (TiO2) is a promising photocatalyst due to its high thermodynamic stability and few intragrain defects. However, it has not yet achieved photocatalytic activity comparable to that of anatase TiO2 owing to its higher recombination rate of electron–hole pairs. To effectively separate the electron–hole pairs in rutile TiO2, a facet heterojunction (FH) structure to prolong the lifetime of the photogenerated electrons is proposed. Ultrathin TiO2 nanosheets with different facets are coated in situ onto TiO2 nanorod (NR) substrates, where FHs are built among the nanosheets as well as between the nanosheets and NR substrates. The as-prepared rutile TiO2, with an FH structure (FH-TiO2), serves as an effective photocatalyst for water splitting. More than 45 and 18 times higher photogenerated current density and H2 production rate, respectively, are obtained compared to those of pure rutile TiO2 NRs. Moreover, FH-TiO2 delivers a 0.566 mmol g?1 h?1 H2 production rate even in pure water. This study offers important insights into the rational design of rutile TiO2 structures for highly efficient photocatalytic reactions.
关键词： charge separation,rutile TiO2,facet heterojunction,water splitting
更新于2025-09-23 15:22:29
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Characterization of Porous SiO2-TiO2 Photocatalyst and the Effect of PEG1000 Concentration
摘要： A porous SiO2-TiO2 photocatalyst was prepared through co-sol-gel method for photocatalytic degradation of methyl orange. PEG1000 was used as a template to induce porous structure in the material. Photocatalytic degradation was conducted after adsorption equilibrium to identify the contribution of both adsorption and photocatalytic degradation. The prepared material was composed of anatase TiO2 and amorphous SiO2. Many small particles formed during grinding also scattered on the surface. The average pore diameter is 16.89 nm and the total pore volume is 0.3644 cm3 g-1 along with specific surface area of 86.27 m2 g-1, as calculated by using BJH and BET methods. The SiO2-TiO2 composite may have the maximum photocatalytic activity and adsorption capacity using 0.04 mol/L of PEG1000 in the precursor.
关键词： Photocatalysis,Composite,TiO2,SiO2
更新于2025-09-23 15:22:29
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Photocatalytic degradation of sulfur black dye over Ce-TiO2 under UV irradiation: removal efficiency and identification of degraded species
摘要： TiO2 and Ce-TiO2 photocatalysts have been synthesized via sol–gel method and characterized by various techniques. Cerium incorporation maintains anatase phase formation, reduces the band gap energy, and inhibits the electron–hole recombination leading to a better photocatalytic response. Photocatalytic activities are explored on the degradation of sulfur black dye under UV light in the presence of H2O2. Photocatalytic reaction parameters have been assessed. Indeed, sulfur black dye color removal reached 92% at the optimal conditions in presence of 1% Ce-TiO2 catalyst. Identification of degradation products of sulfur black dye was achieved by LC/MS.
关键词： Ce-doped TiO2,Photodegradation,LC/MS analysis,Sulfur black dye
更新于2025-09-23 15:22:29
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Photocatalytic Degradation of Reactive Brilliant Red X-3B Based on Microwave Electrodeless Lamp and Long Lifetime Immobilized TiO<sub/>2</sub>
摘要： A novel photocatalytic system (MEL/TiO2/QS) based on microwave electrodeless lamp (MEL) and TiO2 films supported on quartz sheets (TiO2/QS) was established for high photocatalytic efficiency and long catalyst life. The results showed that the degradation efficiency for reactive brilliant red X-3B in MEL/TiO2/QS was equally as that in a suspended TiO2 system. Furthermore, under the microwave irradiation, the TiO2/QS had high catalytic activity after successively used 10 times without additional separation and regeneration. The pseudo-first-order kinetics was employed to describe decomposition of the dye and reaction rates at different initial dye concentrations, followed by the Langmuir–Hinshelwood kinetic model. The mineralization process and final products were also analyzed by total organic carbon (TOC) and ion chromatography (IC). The research might be useful in the commercial scale application of low cost and high efficiency photocatalytic process.
关键词： reactive brilliant red X-3B,Catalyst regeneration,microwave electrodeless lamp,TiO2 films
更新于2025-09-23 15:22:29
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Hierarchical porous TiO2 single crystals templated from partly glassified polystyrene
摘要： Hierarchical macro-mesoporous anatase TiO2 single crystal is one-pot synthesized in an EtOH-H2O system using polystyrene (PS) as the single porogen both for macropore and mesopore and TiF4 as the titanium precursor. The key to the simultaneous growth of single crystal and the introduction of hierarchical pores is the assembly of PS and titania at the glassification temperature of PS (100 °C). During the hydrolytic polymerization of TiF4, PS is encapsulated inside titania and gradually glassified. The interference from elastic PS on the oriental growth of TiO2 crystallite is thus minimized and the final removal of PS through calcination leaves interconnected macropore and mesopore inside the single crystal. According to XPS, EPR and fluorescence analyses, abundant oxygen vacancies are formed on the hierarchical porous single crystal, which presents extraordinary photocatalytic activity and stability in degrading organic pollutants under simulated sunlight irradiation using Rhodamine B as the model. The improved photocatalytic activity is a synergistic effect of improved separation of charge carrier and facilitated interfacial charge transfer benefitting from highly accessible porous single crystal structure.
关键词： Oxygen vacancy,Photocatalysis,Single crystal,Charge transfer,Hierarchical porous TiO2
更新于2025-09-23 15:22:29
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Photodegradation of 2-Chlorophenol in TiO2/UV System: Phytotoxicity Assessment of Treated Solutions Against Seedling Growth of Turnip and Tomato
摘要： The photodegradation and detoxification of 2-chlorophenol (2-CP) in TiO2 suspensions were studied using monochromatic UV-lamp. The effect of pH on the photodegradation of 2-CP was investigated. Removal of 98% of initial 2-CP was achieved within 210 under optimum concentration of 2-CP (60 mg/L) and TiO2 (80 mg/L). The apparent first-order rate constant kapp of 2-CP is estimated to be 0.0043 min–1 at pH 4, while a 3-fold increase in kapp was observed at pH 9. Phytotoxicity effects of treated 2-CP on seed germination, root elongation and plant growth of tomato (Lycopersicon esculentum) and turnip (Brassica rapa) seeds were also carried out with the aim of water reuse and environment protection. No statistically differences have been also found to exist for seed germination of tomato and turnip between deionized water (control) and phototreated 2-CP solution, indicating a significant removal of the overall toxicity. In the 10th day of germination, the average root elongation increases at 210 min of photocatalytic degradation yielding 7.1 ± 0.9 and 5.6 ± 0.66 cm for turnip and tomato seeds, respectively. Turnip plants irrigated with the phototreated 2-CP solution grow in a similar manner as the plant irrigated with the tap water. The phototreated 2-CP can be used in the irrigation of agriculture garden but only after further treatment.
关键词： root elongation,seed germination,TiO2,2-chlorophenol
更新于2025-09-23 15:22:29
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Influence of pyrolytic temperature on optoelectronic properties and the energy harvesting applications of high pressure TiO2 thin films
摘要： The present work deals with the development of a novel photocatalyst to decompose most of the organic pollutants. This work provides a strategy for reproducible high-pressure phases of TiO2 at ambient conditions through nebulizer spray pyrolysis (NSP) technique by varying the substrate temperatures of 200–500 °C using titanium (IV) isopropoxide as a titanium precursor. The structural, morphological, optical and electrical properties of the deposited TiO2 thin films were investigated by using X-ray diffraction, field emission scanning electron microscopy, UV–Visible spectroscopy, Hall effect and temperature dependent resistivity measurements, respectively. The structural analysis confirms that the films deposited at higher substrate temperature are crystallized in TiO2–II phase having polycrystalline nature with good crystalline quality and also pressure induced amorphous phases were also observed for the films deposited at lower substrate temperatures. Deposited films have the uniform surface with homogeneity and porous nature which is suitable for enhanced photocatalytic applications. Electrical measurements show that the films are having n-type behavior with appreciable carrier mobility and concentration. The use of high-pressure TiO2-II phase for higher photocatalytic efficiency was demonstrated.
关键词： Photocatalytic,Methylene blue,TiO2-II phase,Spray pyrolysis
更新于2025-09-23 15:22:29
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Enhanced Photocatalytic Reduction of Cr(VI) by Combined Magnetic TiO2-Based NFs and Ammonium Oxalate Hole Scavengers
摘要： Heavy metal pollution of wastewater with coexisting organic contaminants has become a serious threat to human survival and development. In particular, hexavalent chromium, which is released into industrial wastewater, is both toxic and carcinogenic. TiO2 photocatalysts have attracted much attention due to their potential photodegradation and photoreduction abilities. Though TiO2 demonstrates high photocatalytic performance, it is a difficult material to recycle after the photocatalytic reaction. Considering the secondary pollution caused by the photocatalysts, in this study we prepared Ag/Fe3O4/TiO2 nanofibers (NFs) that could be magnetically separated using hydrothermal synthesis, which was considered a benign and effective resolution. For the photocatalytic test, the removal of Cr(VI) was carried out by Ag/Fe3O4/TiO2 nanofibers combined with ammonium oxalate (AO). AO acted as a hole scavenger to enhance the electron-hole separation ability, thereby dramatically enhancing the photoreduction efficiency of Cr(VI). The reaction rate constant for Ag/Fe3O4/TiO2 NFs in the binary system reached 0.260 min?1, 6.95 times of that of Ag/Fe3O4/TiO2 NFs in a single system (0.038 min?1). The optimized Ag/Fe3O4/TiO2 NFs exhibited high efficiency and maintained their photoreduction efficiency at 90% with a recyclability of 87% after five cycles. Hence, taking into account the high magnetic separation behavior, Ag/Fe3O4/TiO2 NFs with a high recycling capability are a potential photocatalyst for wastewater treatment.
关键词： magnetic property,reusable,photoreduction,photocatalyst,TiO2
更新于2025-09-23 15:22:29
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Photocatalytic and Antimicrobial Properties of Ag2O/TiO2 Heterojunction
摘要： Ag2O/TiO2 heterojunctions were prepared by a simple method, i.e., the grinding of argentous oxide with six different titania photocatalysts. The physicochemical properties of the obtained photocatalysts were characterized by diffuse-reflectance spectroscopy (DRS), X-ray powder diffraction (XRD) and scanning transmission electron microscopy (STEM) with an energy dispersive X-ray spectroscopy (EDS). The photocatalytic activity was investigated for the oxidative decomposition of acetic acid and methanol dehydrogenation under UV/vis irradiation and for the oxidative decomposition of phenol and 2-propanol under vis irradiation. Antimicrobial properties were tested for bacteria (Escherichia coli) and fungi (Candida albicans and Penicillium chrysogenum) under UV and vis irradiation and in the dark. Enhanced activity was observed under UV/vis (with synergism for fine anatase-containing samples) and vis irradiation for almost all samples. This suggests a hindered recombination of charge carriers by p-n heterojunction or Z-scheme mechanisms under UV irradiation and photo-excited electron transfer from Ag2O to TiO2 under vis irradiation. Improved antimicrobial properties were achieved, especially under vis irradiation, probably due to electrostatic attractions between the negative surface of microorganisms and the positively charged Ag2O.
关键词： Ag2O,antimicrobial properties,heterojunction,nanocomposites,heterogeneous photocatalysis,TiO2
更新于2025-09-23 15:22:29
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Bendable Single Crystal Silicon Nanomembrane Thin Film Transistors with Improved Low-Temperature Processed Metal/n-Si Ohmic Contact by Inserting TiO2 Interlayer
摘要： Bendable single crystal silicon nanomembrane thin film transistors (SiNMs TFTs), employing a simple method which can improve the metal/n-Silicon (Si) contact characteristics by inserting the titanium dioxide (TiO2) interlayer deposited by atomic layer deposition (ALD) at a low temperature (90 °C), are fabricated on ITO/PET flexible substrates. Current-voltage characteristics of titanium (Ti)/insertion layer (IL)/n-Si structures demonstrates that they are typically ohmic contacts. X-ray photoelectron spectroscopy (XPS) results determines that TiO2 is oxygen-vacancies rich, which may dope TiO2 and contribute to a lower resistance. By inserting TiO2 between Ti and n-Si, Ids of bendable single crystal SiNMs TFTs increases 3–10 times than those without the TiO2 insertion layer. The fabricated bendable devices show superior flexible properties. The TFTs, whose electrical properties keeps almost unchanged in 800 cycles bending with a bending radius of 0.75 cm, obtains the durability in bending test. All of the results confirm that it is a promising method to insert the TiO2 interlayer for improving the Metal/n-Si ohmic contact in fabrication of bendable single crystal SiNMs TFTs.
关键词： ohmic contact,thin film transistor,single-crystal Si nanomembrane (Si NMs),TiO2 insertion layer
更新于2025-09-23 15:22:29