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Facile synthesis of SiO2@TiO2 hybrid NPs with improved photocatalytic performance
摘要： SiO2@TiO2 hybrid nanoparticles (NPs) were successfully prepared via a simple solvothermal approach using tetrabutyl titanate (Ti(OBu)4) as a titanium source. The morphology and crystal structure of the sample were characterised by scanning electron microscope, transmission electron microscope, and X-ray diffraction. The photocatalytic properties of SiO2@TiO2 hybrid NPs were also investigated in detail. The results showed that the layers of TiO2 NPs have been successfully coated onto the uniform silica sphere and transformed into anatase after calcination at 500°C. In addition, the photocatalytic activity of the as-obtained product was higher than that of the commercial P25-TiO2. The method for producing hybrid NPs has potential applications in building various types of hybrid NPs.
关键词： SiO2@TiO2 hybrid nanoparticles,photocatalytic performance,solvothermal approach,anatase titanium dioxide
更新于2025-09-23 15:21:21
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Role of Pt Loading in the Photocatalytic Chemistry of Methanol on Rutile TiO2(110)
摘要： As a cocatalyst, Pt is well-known for accepting photoexcited electrons and lowering the overpotential of hydrogen production in photocatalysis, being responsible for the enhanced photocatalytic efficiency. Despite the above existing knowledge, the adsorption of reactants on the Pt/photon-absorber (for example, Pt/TiO2) interface, a prerequisite to understand the photocatalytic chemistry, is extremely difficult to investigate mainly due to the complexity of the powdered material and solution environment. Combining ultrahigh vacuum and well-ordered single crystals, we study the photocatalytic chemistry of methanol on Pt loaded rutile TiO2(110) using temperature-programmed desorption (TPD) and ultraviolet photoelectron spectroscopy (UPS). Despite the same photocatalytic chemical products, i.e., formaldehyde and surface hydrogen species, as on Pt-free TiO2(110), the subsequent chemistry of surface hydrogen species and the photocatalytic reaction rate are much different. The bridging hydroxyls desorb as water molecules around 500 K on Pt-free TiO2(110) surface, by contrast, this desorption channel disappears completely and water and molecular hydrogen desorb at much lower temperature (<300 K) after Pt deposition, which can prevent the recombination of hydrogen species with formaldehyde. More importantly, methanol dissociates into methoxy at the Pt/TiO2(110) interface, which is crucial in the photocatalytic chemistry of methanol on TiO2 surfaces since methoxy is a more effective hole scavenger than methanol itself. The photocatalytic chemical reaction rate is increased by nearly one order of magnitude after 0.12 monolayer Pt deposition. This work suggests that Pt loading can promote the dissociation of methanol into methoxy and lower the desorption barrier of molecular hydrogen, which may work cooperatively with separating photoexcited charges to enhance the photocatalytic efficiency. Our work implies the importance of the cocatalysts in affecting the surface structure and adsorption of reactants and products and then improving the photoactivity, in addition to the well-known role in charge separation.
关键词： Titanium Dioxide,Charge Separation,Pt Cocatalyst,Hydrogen Production,Methanol to Methoxy Conversion
更新于2025-09-23 15:21:21
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Effect of thermal oxidation temperatures on the phase evolution and photocatalytic property of tungsten-doped TiO <sub/>2</sub> thin film
摘要： Tungsten-doped titanium dioxide (W-TiO2) thin films were successfully prepared on glass substrates by sputtering thermally oxidized W-doped titanium films in air. Tungsten-doped titanium films were deposited using a DC and RF magnetron cosputtering system. The effects of annealing treatment and W content on the W-TiO2 film microstructure were investigated. The crystalline structures, morphological features, and photocatalytic activity of the annealed W-TiO2 films were systematically studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and ultraviolet spectrophotometry. The results indicated that annealing at 550 °C clearly induced the formation of an anatase and rutile phase mixture in the 5.5 at. % W-TiO2 films, which directly affected photocatalytic activity. The W-TiO2 films showed good photocatalytic activity under UV-light irradiation, with a higher rate of methylene blue dye degradation than in the case of undoped TiO2.
关键词： photocatalytic activity,tungsten-doped titanium dioxide,thermal oxidation,methylene blue degradation,thin films
更新于2025-09-23 15:21:21
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Visible Light TiO <sub/>2</sub> Photocatalyst Composite Based on Carbon Microfiber Derived from Human Hair
摘要： The present work reports titanium dioxide (TiO2) photocatalyst composite based on human hair that can operate efficiently under visible light. The human hair melanin structure contains active sites, which can be described as a carbon compound derived from a Quinone where one of two oxygen atoms is bonded to a hydrogen radical and that can be reversibly photogenerated under visible or ultraviolet irradiation. The human hair-derived microfibers (HHDMs) were created by the pyrolyzing hair at 850 °C, resulting in a rod-like hollow structure. TiO2 was immobilized on the pyrolyzed hair by a simple self-template method. The resulting composite was calcined at five different temperatures (150 to 350 °C). The HHDM and HHDM-TiO2 morphologies and the chemical compositions were characterized using scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD). The HHDM-TiO2 photocatalytic efficiency in degrading methylene blue was investigated and compared to that of a conventional TiO2 catalyst (P25). HHDM-TiO2 was more effective for methylene blue degradation under visible light than the conventional P25 catalyst suspension due to the unique photosensitivity and porous structure of the composite. The catalyst calcined at 300 °C showed the best performance, which was 71% higher than that of the P25 catalyst.
关键词： Semiconductors,Immobilization,Titanium Dioxide,Waste prevention,Photocatalysis
更新于2025-09-23 15:21:21
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Control of Spatially Homogeneous Distribution of Heteroatoms to Produce Red TiO2 Photocatalyst for Visible-Light Photocatalytic Water Splitting
摘要： The strong band-to-band absorption of photocatalysts spanning the whole visible light region (400-700 nm) is critically important for solar-driven photocatalysis. Although it is actively and widely used as photocatalyst for various reactions in the past four decades, TiO2 has a very poor ability to capture the whole-spectrum visible light. Here, by controlling the spatially homogeneous distribution of boron and nitrogen heteroatoms in anatase TiO2 microspheres with a predominance of high-energy {001} facets, a strong visible light absorption spectrum with a sharp edge beyond 680 nm is achieved. The red TiO2 with the homogeneous doping of boron and nitrogen obtained shows no increase in defects like Ti3+ that are commonly observed in doped TiO2. More importantly, it has the ability to induce photocatalytic water oxidation to produce oxygen under the irradiation of visible light beyond 550 nm and also photocatalytic reducing water to produce hydrogen under visible light. These results demonstrate the great promise of using the red TiO2 for visible light photocatalytic water splitting and also provide an attractive strategy for realizing the wide-spectrum visible light absorption of wide-bandgap oxide photocatalysts.
关键词： Titanium Dioxide,Photocatalysis,Water Splitting,Homogeneous Doping,Visible Light
更新于2025-09-23 15:21:21
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Biomolecular interaction and kinematics differences between P25 and E171 TiO2 nanoparticles
摘要： Titanium dioxide (TiO2) nanoparticles (NPs) are used abundantly as food additives (E171). For the purpose of risk assessment, it is imperative to understand the behavior of these nanoparticles in a food relevant environment, and their consequent toxicology impacts. However, most of such studies use model TiO2 NPs (P25) as substitutes for E171. To understand the suitability of this approach, we investigated the functional behavior of E171 and P25 in solutions of bovine serum albumin (BSA) and sucrose as model food ingredients. Our data showed that E171 were better dispersed in BSA than P25. In sucrose, E171 displayed a reduction in agglomerated size while P25 agglomerated extensively. Adsorption studies showed that P25 attracted more pronounced corona formation per unit mass of material compared to E171. In vitro sedimentation, diffusion and dosimetry (ISDD) results demonstrated that the time-weighted dosage of E171 was more than two-folds higher than P25, implying that any test performed using P25 to model E171 would underestimate actual dosage and potential toxicity. Taken collectively, this study demonstrated the specificity of TiO2 nanoparticle interaction with food ingredients, and the importance of using food-grade E171 TiO2 for food-relevant toxicological assessments.
关键词： ISDD,Nanoparticles,Titanium dioxide,Sucrose,Corona,Protein
更新于2025-09-23 15:21:21
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Modulating the photocatalytic activity of TiO2 (P25) with lanthanum and graphene oxide
摘要： The modulation and tuning of the photocatalytic activity of commercial titanium dioxide (TiO2) P25 nanoparticles is demonstrated through the incorporation of lanthanum (La) and/or graphene oxide (GO). These composite materials, which could have applications in commercial products, were prepared by a two-step hydrothermal method from the corresponding precursors. The effect of La (0.05 - 2 mol%) and GO (5 m%) content on the crystal structure, morphology and photocatalytic activity of TiO2 was investigated by XRS, SEM, EDS, TEM, UV-visible DRS, point of zero charge, photoluminescence and the decolorization of methylene blue. Lanthanum modified the recombination rate of the photogenerated electron-hole charges on TiO2 by inducing an increase in the structural defects, which resulted in a significant suppression, up to 90%, of the photocatalytic activity in the UVA light region. In contrast, the addition of GO enhanced the photocatalytic activity of TiO2. Materials with tuned intermediate photoactivity within the entire range from high to very low were prepared by dosing appropriate amounts of La and GO species. The strategy of combining La and GO represents a useful and simple method for tuning or for suppressing the photocatalytic activity of TiO2 under UVA light irradiation in materials and consumer products using TiO2.
关键词： lanthanides,rare earths,titanium dioxide,graphene oxide
更新于2025-09-23 15:21:21
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Low-temperature-dependent growth of titanium dioxide nanorod arrays in an improved aqueous chemical growth method for photoelectrochemical ultraviolet sensing
摘要： The growth of titanium dioxide nanorod arrays (TNAs) in aqueous solutions containing titanium butoxide and hydrochloric acid can be controlled by regulating the temperature from 115 to 150 °C as an adjustable physical parameter. The transparent colloidal solution of titanates is clouded on the basic growth of TNAs when heated at a certain temperature using an improved aqueous chemical growth method in a clamped Schott bottle. The structural, optical and electrical properties of grown TNAs films were thoroughly investigated and discussed. The distinct and high-intensity peaks observed in the X-ray diffraction pattern and Raman spectra of the grown TNAs show the rutile phase with high crystal quality. The crystallite size, diameter size, and thickness of TNAs decrease with decreasing growth temperature. The prepared TNAs were used to detect 365 nm ultraviolet (UV) photon energy (750 μW/cm2) in a photoelectrochemical cell structure with a maximum photocurrent of 26.31 μA and minimum photocurrent of 3.48 μA recorded for TNAs grown at 150 °C and 115 °C, respectively. The size, structural properties, charge transfer resistance, and electron lifetime play a key role in determining the UV sensing characteristics of the TNAs. Results show that TNAs are very promising in fabricating a UV sensor with a high response at 0 V bias even at a low growth temperature of 115 °C.
关键词： Photoelectrochemical ultraviolet sensing,Titanium dioxide nanorod arrays,Rutile phase,Aqueous chemical growth method,UV sensor
更新于2025-09-23 15:21:21
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Suppressing Shallow Defect of Printable Mesoscopic Perovskite Solar Cells with a N719@TiO <sub/>2</sub> Inorganic-Organic Core-Shell Structured Additive
摘要： Shallow defects are one of the energy states that trap photoexcited electrons leading to charge recombination and limit the increase in the photocurrent of perovskite solar cells (PSCs). Due to the large perovskite thickness and uncontrollable crystallization processes, suppressing shallow defects, especially methylamine (MA) vacancies, has become a key challenge for fully printable PSCs. Herein, nano-TiO2 is unprecedentedly used to load the commercial dye N719, forming N719@TiO2 nanoparticles, which crucially improves the passivation effect of MA vacancies on the surface of perovskite and charge extraction, by the unbounded carboxyl group of N719 as a shell on the surface of TiO2. Meanwhile, the core TiO2 serves as a centre to bind the dyes, assisting the perovskite crystallization and enhancing the passivation effect. It is found that the charge extraction increases to 1.8007 (cid:1) 10 N719@TiO2 from 1.5507 (cid:1) 10 short-circuit current density (Jsc) is signi?cantly enhanced to 23.58 mA cm in the device containing N719@TiO2 over that of the control device (21.95 mA cm PSCs via organic passivator with carboxyl anchoring group loaded on n-type semiconductors (nano-TiO2).
关键词： passivation,printable solar cells,dyes,titanium dioxide,perovskite solar cells
更新于2025-09-23 15:21:01
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Hydrogen Sulfide Gas Sensor Based on Titanium Dioxide/Amino-Functionalized Graphene Quantum Dots Coated Photonic Crystal Fiber
摘要： A novel photonic crystal fiber (PCF) Mach-Zehnder interferometer (MZI) was proposed for detecting hydrogen sulfide (H2S) gas. Two single-mode fibers (SMFs), two multi-mode fibers (MMFs), and a PCF are sequentially fused to form a MZI with SMF-MMF-PCF-MMF-SMF structure. Titanium dioxide/amino-functionalized graphene quantum dots (TiO2/af-GQDs) composite is coated on the surface of PCF as sensing membrane. The fabricated sensing membrane is characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Furthermore, the properties of the sensor are examined. The results show that a uniform TiO2/af-GQDs film with a thickness of 1 μm is successfully coated on the surface of the PCF. The sensor has a sensitivity of 26.62 pm/ppm, showing a good linearity and selectivity for H2S in the range of 0~55 ppm. The response time and recovery time are about 68 s and 77 s, respectively. The sensor has the advantages of low cost, small volume and simple structure, which is suitable for on-line monitoring of H2S.
关键词： Mach-Zehnder interference,Graphene quantum dots,Titanium dioxide,Fiber-optic sensing,Hydrogen sulfide
更新于2025-09-23 15:21:01