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Morphology Phase Diagram of Slot‐Die Printed TiO <sub/>2</sub> Films Based on Sol–Gel Synthesis
摘要： Mesoporous titania films with tailored nanostructures are fabricated via slot-die printing, which is a simple and cost-effective thin-film deposition technique with the possibility of a large-scale manufacturing. Based on this technique, which is favorable in industry, TiO2 films possess the similar advantage with polymer semiconducting devices like ease of large-scale production. The titania morphologies, including foam-like nanostructures, nanowire aggregates, collapsed vesicles and nanogranules, are achieved via a so-called block-copolymer-assisted sol–gel synthesis. By adjusting the weight fraction of reactants, the ternary morphology phase diagram of the printed titania films is probed after template removal. The surface and inner morphology evolutions are explored with scanning electron microscopy and grazing incidence small-angle X-ray scattering, respectively. Special focus is set on foam-like titania nanostructures as they are of especial interest for, e.g., solar cell applications. At a low weight fraction of the titania precursor titanium(IV)isopropoxide (TTIP), foam-like titania films are achieved, which exhibit a high uniformity and possess large pore sizes. The anatase phase of the highly crystalline titania films is verified with X-ray diffraction and transmission electron microscopy.
关键词： TiO2 films,crystallinity,morphology phase diagram,printing,GISAXS
更新于2025-11-21 11:20:42
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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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Laser-Generated Ag Nanoparticles in Mesoporous TiO2 Films: Formation Processes and Modeling-Based Size Prediction.
摘要： Controlling the formation of nanoparticles (NPs) by direct laser writing ensures an efficient way of engineering the optical responses of nanocomposite materials through adjusting laser parameters such as power, focusing and writing speed. The process of NP’s growth, photo-oxidation, and reduction affect the light absorption by an ensemble of laser-activated NPs. However, those self-consistent processes are not well understood. Previous studies explained the growth or shrinkage of silver NPs by neglecting heat diffusion. It remained unclear, however, how the NP size can be controlled by the laser writing speed. In this work, based on the coupled calculations of size-variation, light absorption, and heat diffusion by an emsemble of NPs, we propose a two-dimensional model taking account of spatial information of size and temperature to have a further investigation into the process. The spatial size distribution is revealed to be non-uniform leading to the transmission inhomogeneity along the laser written lines. This fact is confirmed by the in-situ transmission experiments. The performed study also depicts a novel view in which NPs grow ahead of the laser beam center due to the heat diffusion. The nonlinear growth never stops until it exhausts the majority of the free Ag0 in the matrix, while the amount of Ag0 by reduction cannot compensates the consumption. After that, the photo-oxidation dominates the process and finally acts as the controlling role in NP size depending on the writing speed. The simulations also show that it is not the activation energy of Ag0 diffusion but the ionization efficiency affect the final NP size, which helps understand in how to improve the laser processing of differently prepared samples.
关键词： photo-oxidation,silver nanoparticles,nanoparticles,TiO2 films,laser writing,heat diffusion
更新于2025-09-16 10:30:52
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Real time nanoplasmonic sensing for monitoring CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> perovskite formation in mesoporous TiO <sub/>2</sub> films
摘要： The formation of methylammonium lead iodide (CH3NH3PbI3) perovskite into mesoporous titania (TiO2) scaffold via a sequential deposition method is known to offer high quality films for good photovoltaic device performance. The local kinetics at the lower interface between the mesoporous TiO2 film and the collecting electrode govern perovskite growth and formation. Here, we have used a NanoPlasmonic Sensing (NPS) approach with gold (Au) nanosensors to monitor the formation of CH3NH3PbI3 perovskite at the lower interface of up to 650 nm mesoporous TiO2 films. This technique provides time-resolved spectral shifts of the localized surface plasmon resonance at different operating temperatures and methylammonium iodide (CH3NH3I3) concentrations by recording changes in the local vicinity of the Au nanosensors at the mesoporous TiO2 film interface. Analytical studies included ellipsometry, scanning electron microscopy, X-ray diffraction, and photoluminescence spectroscopy. The results show that both the intensity of the NPS response and NPS rate constants are correlated with the operating concentrations and temperatures of CH3NH3I3 as well as CH3NH3PbI3 perovskite growth in mesoporous TiO2.
关键词： nanoplasmonic sensing,localized surface plasmon resonance,mesoporous TiO2 films,perovskite formation,CH3NH3PbI3
更新于2025-09-16 10:30:52
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Simple TiO <sub/>2</sub> Coatings by Sol–Gel Techniques Combined with Commercial TiO <sub/>2</sub> Particles for Use in Heterogeneous Photocatalysis
摘要： TiO2 coatings were obtained by a combination of a sol–gel process with the addition of commercial TiO2 particles (Degussa-Evonik P25). Simple and composite (with P25) sols were deposited by dip-coating on glass plates giving simple and composite coatings. The order of addition of reagents in the preparation of sols, the incorporation of P25 to the sols, and the thermal treatments were analyzed as variables to improve the photocatalytic activity. The samples were completely characterized with respect to the amount of deposited TiO2, the crystal structure (XRD) and the morphology (SEM). The activity of the supported photocatalysts (simple, composite and P25 coatings) was evaluated using 4-chlorophenol degradation and Cr(VI) reduction in the presence of EDTA as model photocatalytic systems. The stability of sols and the photocatalytic activity of the resulted coatings depended strongly on the order of addition of the reagents to obtain the simple sol. Sols prepared by adding the alcohol-water-HCl mixture to the precursor were the simple sols presenting a very good stability that permitted the incorporation of powdered P25 without the addition of additives. The composite coatings prepared from these simple sols were the most active in both photocatalytic systems and also presented the highest resistance to scratch.
关键词： TiO2 Films,Sol–Gel,Heterogeneous Photocatalysis
更新于2025-09-09 09:28:46