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A brief overview of molecularly imprinted polymers supported on titanium dioxide matrices
摘要： Molecularly imprinted polymer (MIP) is a polymer competent of mimicking selective binding of target or template molecule, which is characteristic of enzyme and antibodies. MIP has a wide range of applications in various fields of science and can be used as a sensor, catalyst, drug delivery component, etc. To overcome some demerits of MIP, the process of formation of imprinting cavity was carried out by nanoimprinting materials, which enables the imprinting technique to create more effective recognition sites than those obtained by traditional approaches. Here, in this article, we described a brief account of various discoveries happened in titanium dioxideebased molecularly imprinted polymeric system that shows a wide variety of chemical applications. The intention of this article is to provide comprehensive knowledge and information to all researchers who are interested in exploiting molecular imprinting technology toward the rational design of various chemical sensors operating on different transduction principles, ranging from electrochemical to piezoelectric, being used for the detection of different template molecules as they pose considerable impact on the understanding of the origin of life and all processes that occur in living organisms.
关键词： Applications,Titanium dioxide,Molecular imprinting,Imprinted structures
更新于2025-09-23 15:23:52
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Enzymatic sensor for phenols based on titanium dioxide generating surface confined ROS after treatment with H2O2
摘要： Titanium dioxide (TiO2) is a popular material as host matrix for enzymes. We now evidence that TiO2 can accumulate and retain reactive oxygen species after treatment by hydrogen peroxide (H2O2) and support redox cycling of a phenolic analyte between horseradish peroxidase (HRP) and an electrode. The proposed detection scheme is identical to that of second generation biosensors, but the measuring solution requires no dissolved H2O2. This significantly simplifies the analysis and overcomes issues related to H2O2 being present (or generated) in the solution. The modified electrodes showed rapid stabilization of the baseline, a low noise level, fast realization of a steady-state current response, and, in addition, improved sensitivity and limit of detection compared to the conventional approach, i.e. in the presence of H2O2 in the measuring solution. Hydroquinone, 4-aminophenol, and other phenolic compounds were successfully detected at sub-μM concentrations. Particularly, a linear response in the concentration range between 0.025 and 2 μM and LOD of 24 nM was demonstrated for 4-aminophenol. The proposed sensor design goes beyond the traditional concept with three sensors' generations offering a new possibility for the development of enzymatic sensors based on peroxidases and the formation of ROS on titania after treatment with H2O2.
关键词： Hydroperoxyl species,Titanium dioxide,Horseradish peroxidase,Bioelectrochemistry,Hydrogen peroxide
更新于2025-09-23 15:23:52
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Adsorption and photocatalytic oxidation of ibuprofen using nanocomposites of TiO2 nanofibers combined with BN nanosheets: Degradation products and mechanisms
摘要： This study investigated the adsorption and photocatalytic activity of TiO2-boron nitride (BN) nanocomposites for the removal of contaminants of emerging concern in water using ibuprofen as a model compound. TiO2 nanofibers wrapped by BN nanosheets were synthesized by electrospinning method. Characterization of the nanocomposite photocatalysts indicated the BN nanosheets improved the light absorbance and reduced the recombination of the photoexcited charge carriers (e- and h+). The photocatalytic oxidation products and mechanisms of ibuprofen by the TiO2-BN catalysts were elucidated using a multiple analysis approach by high performance liquid chromatography, ultraviolet absorbance, dissolved organic carbon, fluorescence excitation-emission matrices, and electrospray ionization–liquid chromatography–tandem mass spectrometry. The experimental results revealed that the photocatalytic oxidation by the TiO2-BN nanocomposites is a multi-step process and the interactions between ibuprofen molecules and the TiO2-BN nanocomposites govern the adsorption process. The increasing BN nanosheet content in the TiO2 nanofibers facilitated the breakdown of ibuprofen degradation intermediates (hydroxyibuprofen, carboxyibuprofen, and oxypropyl ibuprofen). Kinetic modeling indicated both adsorption and photocatalytic oxidation of ibuprofen by the TiO2-BN nanocomposites followed the first-order kinetic model. The photocatalytic oxidation rate increased with the increasing BN content in the nanocomposite catalysts, which was attributed to the enhanced light absorption capacity and the separation efficiency of the photoexcited electron (e-)-hole (h+) pairs. Multiple photocatalytic cycles were conducted to investigate the reusability and regeneration of the nanofibers for ibuprofen degradation.
关键词： adsorption,titanium dioxide boron-nitride nanocomposites,photocatalytic degradation mechanisms,degradation intermediates,photocatalytic oxidation
更新于2025-09-23 15:23:52
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A comparison of water photo-oxidation and photo-reduction using photoelectrodes surface-modified by deposition of co-catalysts: Insights from photo-electrochemical impedance spectroscopy
摘要： The purpose of this research paper is to highlight the similarities in the kinetic treatment between water photo-oxidation into molecular oxygen and water photo-reduction into molecular hydrogen, using photoelectrodes surface modified by deposition of co-catalysts. Photo-anodes made of TiO2 nanorods surface-covered by crystals of cobalt Zeolitic Imidazolate Framework (ZIF-67), and photo-cathodes made of Rh:SrTiO3 particles surface-modified by adsorption of molecules of trisdioximate hexa-chlorine cobalt (II) clathrochelate (Co(Cl2Gm)3(BCH3)2), have been prepared and used for water photo-oxidation and photo-reduction experiments, respectively. Both photoelectrodes have been characterized by SEM and cyclic voltammetry under illumination conditions. Charge transfer mechanisms have been investigated by photo-electrochemical impedance spectroscopy (PEIS). It is shown that for both systems, the presence of a co-catalyst increases the charge transfer kinetics, and that the trapping resistance is larger than the charge transfer resistance, at any operating potential.
关键词： Water photo-oxidation,Titanium dioxide nanorods,Strontium titanate,Water photo-reduction,ZIF-67 MOF
更新于2025-09-23 15:23:52
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A new insight for photocatalytic hydrogen production by a Cu/Ni based cyanide bridged polymer as a co-catalyst on titania support in glycerol water mixture
摘要： A two dimensional Cu/Ni based coordination polymer (CP-1) $0.7(C2H6O2)$1.6(H2O) (4,4?-dipy ? 1,3-di(4-pyridyl)propane) has been demonstrated as a potential co-catalyst on TiO2 support for hydrogen evolution under UV light. CP-1/TiO2 composite exhibits considerable hydrogen production in comparison with the pristine CP-1 and TiO2 (P25), highlighting that the photocatalytic performance is significantly related with the good separation of photo generated e-/h+ pairs. Different wt. % (2.5, 5 and 7.5%) of CP-1 in CP-1/TiO2 composites were tested for photocatalytic hydrogen production in 5 vol % glycerol/water mixture. The 5 wt % CP-1/TiO2 composite displayed the greatest hydrogen production of 9.2 mmol h-1 g-1. The concealed mechanism is divulged on the behalf of results obtained by cyclic voltammetry, photoluminescence and diffused reflectance/UV-visible studies which demonstrate that upon irradiation of UV light, electrons transfer from TiO2 conduction band to CP-1. CP-1 not only grabs the conduction band electrons of titania but also performes as a co-catalyst to reduce the protons into hydrogen. These results are anticipated to direct the forthcoming advancement in creating proficient, cheap semiconductor photocatalysts for solar hydrogen production.
关键词： Hydrogen,Coordination polymer,Co-catalyst,Photocatalyst,Titanium dioxide
更新于2025-09-23 15:23:52
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Comparing the Efficiency of N-Doped TiO2 and N-Doped Bi2MoO6 Photo Catalysts for MB and Lignin Photodegradation
摘要： In this study, we tested the efficiency of nitrogen-doped titanium dioxide (N-TiO2) and nitrogen-doped bismuth molybdate (N-Bi2MoO6) compounds as photocatalysts capable of degrading methylene blue and lignin molecules under irradiation with ultraviolet (UV) and visible light (VIS). Moreover, we compared TiO2 and Bi2MoO6 catalysts with N-TiO2 and N-Bi2MoO6 compounds using chemical coprecipitation. The catalysts were prepared starting from Ti(OCH2CH2CH3)4, Bi(NO3)3·5H2O, and (NH4)6Mo7O24 reagents. N-doping was achieved in a continuous reflux system, using ethylene diamine as a nitrogen source. The resulting materials were characterized using Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Additionally, we observed the decrease in particle size after processing the compounds in the reflux system. The results regarding photocatalytic degradation tests show a remarkable effect for nitrogen doped samples, achieving 90% of lignin degradation.
关键词： photocatalysis,lignin,visible light,UV light,bismuth molybdate,Titanium dioxide
更新于2025-09-23 15:23:52
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Optimizing one-dimensional TiO2 for photocatalytic hydrogen production from a water-ethanol mixture and other electron donors
摘要： This work is focused on synthesizing and employing one-dimensional (1D) titanium dioxide (TiO2) for hydrogen (H2) production. Based on using electron donors (EDs) (ethanol, methanol, formic acid and 1,2,3 propanetriol), the increased H2 production, when compared to P25 TiO2 nanoparticles, was due to the large specific surface area (SSA) and enhanced electron mobility of 1D TiO2. The impact of the 1D TiO2 synthesis reaction conditions (temperature, NaOH concentration and the TiO2 precursor concentration) on the photocatalytic H2 production rate was evaluated using a 3-factor 3-level Box Behnken design (BBD). The BBD model demonstrated that the temperature and the NaOH concentration significantly affected the 1D TiO2 phase structure, crystal size, SSA, bandgap and the photocatalytic H2 production rate. The phase structure and crystal size of 1D TiO2 were key factors affecting the H2 production rate. 1D TiO2 containing an anatase phase with a mean crystal size of 20.1±0.2 nm was synthesized at 126oC, 15 M NaOH and 49 g·L-1 TiO2. The maximum H2 production rate of 475±12 μmol·h-1 (quantum efficiency (ε) = 20.2±0.5%) for the 1D TiO2 sample was significantly enhanced when compared to commercial TiO2 P25. The H2 production rate for the optimized 1D TiO2 was significantly enhanced by decorating the structure with Pt and Au. Hydrothermal synthesized of 1D TiO2 provided an efficient and low cost method for producing H2 from ethanol, methanol, formic acid and 1,2,3 propanetriol.
关键词： hydrogen production,hydrothermal,1D titanium dioxide,TiO2-B,anatase,photocatalyst,quantum yield
更新于2025-09-23 15:23:52
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Metal–organic framework coated titanium dioxide nanorod array p–n heterojunction photoanode for solar water-splitting
摘要： This paper presents a p–n heterojunction photoanode based on a p-type porphyrin metal–organic framework (MOF) thin film and an n-type rutile titanium dioxide nanorod array for photoelectrochemical water splitting. The TiO2@MOF core–shell nanorod array is formed by coating an 8 nm thick MOF layer on a vertically aligned TiO2 nanorod array scaffold via a layer-by-layer self-assembly method. This vertically aligned core–shell nanorod array enables a long optical path length but a short path length for extraction of photogenerated minority charge carriers (holes) from TiO2 to the electrolyte. A p–n junction is formed between TiO2 and MOF, which improves the extraction of photogenerated electrons and holes out of the TiO2 nanorods. In addition, the MOF coating significantly improves the efficiency of charge injection at the photoanode/electrolyte interface. Introduction of Co(III) into the MOF layer further enhances the charge extraction in the photoanode and improves the charge injection efficiency. As a result, the photoelectrochemical cell with the TiO2@Co-MOF nanorod array photoanode exhibits a photocurrent density of 2.93 mA/cm2 at 1.23 V (vs. RHE), which is ~ 2.7 times the photocurrent achieved with bare TiO2 nanorod array under irradiation of an unfiltered 300 W Xe lamp with an output power density of 100 mW/cm2.
关键词： p–n junction,photoanode,titanium dioxide,metal-organic framework,water-splitting
更新于2025-09-23 15:23:52
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Application of quantitative light-induced fluorescence technology for tooth bleaching treatment and its assessment: An in vitro study
摘要： Objectives: This study aimed to determine the effectiveness of combination of photocatalysts - low concentration of hydrogen peroxide (3.5%) and titanium dioxide (TiO2), activated at a wavelength of 405 nm using quantitative light-induced fluorescence (QLF) technology, and to quantify the tooth-bleaching effect using fluorescence images from QLF technology. Materials and Methods: Forty bovine incisors were extrinsically stained according to Stookey’s method. Two bleaching solutions were prepared by mixing 3.5% H2O2 with 0.05% of anatase and rutile nano-TiO2 powder. These solutions were applied to the stained teeth using a micro-brush and then irradiated for 15 minutes at either 306 or 405 nm to activate the bleaching agent. The color difference was assessed before and after every 5 minutes of treatment. The ?E and ?F were obtained from white-light and fluorescence images, respectively. Results: All the low H2O2/TiO2 treatments caused significant bleaching after irradiation at 306 and 405 nm (p<0.05). There was no significant difference between the wavelengths (p>0.05), but a greater bleaching effect was obtained with anatase-TiO2 at 306 nm and rutile-TiO2 at 405 nm. Analysis of the fluorescence images revealed that the ?F values decreased significantly in all the groups according to the treatment times (p<0.05). There was a statistically significant reverse correlation between ?E and ??F (r= -0.822, p<0.001). Conclusions: Low H2O2/TiO2 with 405 nm of QLF technology demonstrated greater bleaching effect. Furthermore, the fluorescent images from QLF technology showed a possibility for assessment of tooth bleaching.
关键词： Digital imaging,Tooth bleaching,Theragnosis,405 nm wavelength,Titanium dioxide,Quantitative light-induced fluorescence (QLF)
更新于2025-09-23 15:23:52
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Electrostatically Directed Assembly of Nanostructured Composites for Enhanced Photocatalysis
摘要： It is well established that the activity of photocatalysts can be improved by deposition of redox catalysts, which can effectively extract the photogenerated charge carriers, enhance the rate of interfacial reactions, and thus suppress undesired recombination processes. For optimum performance, a high degree of control over the loading, size, and surface catalytic properties of redox catalyst particles is desirable. Herein, a novel, highly controllable, and versatile method for preparation of TiO2 catalyst composites is reported. It starts with the generation of “naked” (ligand-free) nanoparticles of CuOx or FeOx by pulsed laser ablation of metal oxide targets in water. In the next step, a nearly quantitative colloidal deposition of CuOx and FeOx nanoparticles onto anatase TiO2 substrate is achieved by adjusting the pH in order to establish electrostatic attraction between the colloids and the substrate. The resulting TiO2–CuOx and TiO2–FeOx assemblies with optimum catalyst amount (≈0.5 wt%) exhibit photocatalytic rates in degradation of 2,4-dichlorophenoxyacetic acid enhanced by a factor of ≈1.5 as compared to pristine TiO2 under simulated solar irradiation. The electrostatically directed assembly of TiO2 with ligand-free catalyst nanoparticles generated by pulsed laser ablation is thus demonstrated as a viable tool for preparation of composites with enhanced photocatalytic performance.
关键词： photocatalysis,titanium dioxide,laser ablation,colloidal deposition,nanoparticles
更新于2025-09-23 15:23:52