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Photo-Sensitive Pb5S2I6 Crystal Incorporated Polydopamine Biointerface Coated on Nanoporous TiO2 as an Efficient Signal-on Photoelectrochemical Bioassay for Ultrasensitive Detection of Cr(VI) ions
摘要： An ultrasensitive Visible light-triggered photoelectrochemical (PEC) sensor was designed based on ideal photoactive lead sulfoiodide (Pb5S2I6) as low band gap crystal, which hydrothermally synthesized rapidly at low temperature (160°C) in hydrochloride acid media followed by its incorporation into polydopamine as reactive photo-biointerface, through a facile in situ electropolymerization method, coated on nanoporous TiO2 grown by anodization on Ti foil. The structure of as-prepared samples and their photoelectrochemical properties were fully characterized. This unique photo-sensitive Pb5S2I6 catalyst-based PEC bioassay was constructed for the detection of low-abundant Cr(VI) ion in real samples. Applying central composite design, individual and mutual interaction effects were evaluated to obtain optimized solution pH, applied potential and radiant light wavelength as operational factors influencing the PEC efficiency for Cr(VI) detection. At optimal condition, the proposed sensor due to effective suppress in electron–hole recombinations showed a very low detection limit of 3.0 nM, over a broad linear concentration range of 0.01 μM-80 μM in addition to high sensitivity versus 1.9 μA/μM Cr(VI). Proposed PEC sensor displayed high selectivity, reproducibility and stability as well as improved excitation conversion efficiency, which make it highly applicable using solar energy. The potential applicability of the designed sensor was evaluated in water, tomato juice and hair color.
关键词： Photoelectrochemical biosensor,Nanoporous TiO2,Cr(VI) ions,Visible light excitation.,Pb5S2I6 crystal
更新于2025-11-21 11:01:37
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Spray pyrolysis synthesis of mesoporous TiO2 microspheres and their post modification for improved photocatalytic activity
摘要： Mesoporous TiO2 microspheres were prepared by spray pyrolysis for photocatalysis. Post modification of TiO2 by heat treatment was performed to optimize its photocatalytic performance. First, spherical TiO2 particles with mesoporous structure were synthesized at pyrolysis temperatures of 500, 600, and 700 oC. After characterization by XRD, SEM, and N2 adsorption, a sample prepared at 500 oC was found to possess desirable properties for photocatalytic performance through post-modification. In methylene blue degradation, mesoporous TiO2 microspheres synthesized at 500 oC outperformed other microspheres. Furthermore, samples obtained by spray pyrolysis at 500 oC were calcined at various temperatures as a post-modification process. The sample calcined at 350 oC showed improved photocatalytic activity due to optimal anatase crystallinity and surface area.
关键词： Spray Pyrolysis,MB Degradation,Post Modification,Mesoporous TiO2 Spheres
更新于2025-11-21 10:59:37
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Photocatalytic properties of TiO2@Polymer and TiO2@Carbon aerogel composites prepared by atomic layer deposition
摘要： Monolithic structured TiO2/aerogel composites were prepared from resorcinol-formaldehyde polymer aerogel (RFA) and its carbon aerogel (RFCA) derivative. A resorcinol-formaldehyde hydrogel was synthesized in a sol-gel reaction and transformed into polymer aerogel by supercritical drying. The RFA was converted to carbon aerogel by pyrolysis at 900 °C in dry N2. Amorphous and crystalline TiO2 layers were grown from TiCl4 and H2O precursors by atomic layer deposition (ALD) at 80 °C and 250 °C, respectively, on both RFA and RFCA. The substrates and the composites were studied by N2 adsorption, TG/DTA-MS, Raman, SEM-EDX and TEM techniques. Their photocatalytic activity was compared in the UV catalyzed decomposition reaction of methyl orange dye.
关键词： ALD,photocatalysis,carbon aerogel,TiO2,resorcinol-formaldehyde polymer aerogel
更新于2025-11-20 15:33:11
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The coherence between TiO2 nanoparticles and microfibrillated cellulose in thin film for enhanced dispersal and photodegradation of dye
摘要： Microfibrillated cellulose (MFC) was used to enhance the dispersal and photocatalytic properties of TiO2 nanoparticles. With the small amount of MFC (0.1 wt.% or 0.3 wt.%), TEM images showed that particle agglomeration was greatly minimized due to the coherence between TiO2 nanoparticles and MFC. The surface area and pore volume of TiO2 nanoparticles was enhanced as proven in N2 adsorption-desorption analysis. Thermogravimetric and Fourier transform infrared spectra further confirmed the presence of MFC in TiO2/MFC coating solution. Using commercial adhesive, TiO2 and TiO2/MFC were spray coated on polyvinyl chloride sheet. The photocatalytic thin films were examined using scanning electron microscope with Energy dispersive X-ray analysis. The presence of MFC was not only helpful to enhance particle dispersal but also supportive to increase the hydrophilicity of the thin film. In comparison to TiO2 coating, the films were capable to adsorb 50% more methylene blue in 90 min. TiO2/MFC coatings removed 90% of methylene blue dye in 90 min under UV irradiation.
关键词： Spray coating,Photocatalysis,Dye,TiO2 nanoparticles,Microfibrillated cellulose,Adsorption
更新于2025-11-19 16:56:35
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Enhanced photocatalytic performance of TiO2 NTs decorated with chrysanthemum-like BiOI nanoflowers
摘要： The BiOI nanosheets/chrysanthemum-like nanoflowers were successfully deposited on the surface of TiO2 nanotube arrays (TiO2 NTs) by the successive ionic layer adsorption and reaction (SILAR) method, and the morphology and visible light response of samples with different SILAR deposition cycles were investigated in detail. The as-prepared BiOI/TiO2 NTs significantly enhanced photoelectrocatalytic (PEC) activity for the removal of Methyl orange (MO), Rhodamine B (RhB), Methylene blue (MB) and Cr(VI). The as-prepared Sample-7 with chrysanthemum-like nanostructures showed the high visible light photocurrent density of 120.06 μA/cm2, photovoltage of ?203.61 mV/cm2, PEC efficiencies of 45%, 62%, 79% and 77% for the removal of MO, RhB, MB and Cr(VI), respectively. The high PEC performances could be ascribed to the excellent visible light response and charge carrier transportation in chrysanthemum-like BiOI nanoflowers. By further probing the charge separation and transportation behaviors, the experiments of the energy band structure and active species trapping were carried out. A possible p-n heterojunction photocatalytic mechanism was proposed, which not only benefited the efficient separation of photogenerated electrons but also demonstrated the advanced capacity for the PEC removal of organic dyes and heavy metal ions.
关键词： BiOI,Photoelectrochemical performance,TiO2 nanotube arrays,Nanoflowers
更新于2025-11-19 16:56:35
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Adsorption and Photocatalytic Decomposition of Gaseous 2-Propanol Using TiO2-Coated Porous Glass Fiber Cloth
摘要： Combinations of TiO2 photocatalysts and various adsorbents have been extensively investigated for eliminating volatile organic compounds (VOCs) at low concentrations. Herein, TiO2 and porous glass cloth composites were prepared by acid leaching and subsequent TiO2 dip-coating of the electrically applied glass (E-glass) cloth, and its adsorption and photocatalytic ability were investigated. Acid leaching increased the specific surface area of the E-glass cloth from 1 to 430 m2/g while maintaining sufficient mechanical strength for supporting TiO2. Further, the specific surface area remained large (290 m2/g) after TiO2 coating. In the photocatalytic decomposition of gaseous 2-propanol, the TiO2-coated porous glass cloth exhibited higher adsorption and photocatalytic decomposition ability than those exhibited by the TiO2-coated, non-porous glass cloth. The porous composite limited desorption of acetone, which is a decomposition intermediate of 2-propanol, until 2-propanol was completely decomposed to CO2. The CO2 generation rate was affected by the temperature condition (15 or 35 °C) and the water content (2 or 18 mg/L); the latter also influenced 2-propanol adsorption in photocatalytic decomposition. Both the conditions may change the diffusion and adsorption behavior of 2-propanol in the porous composite. As demonstrated by its high adsorption and photocatalytic ability, the composite (TiO2 and porous glass cloth) effectively eliminates VOCs, while decreasing the emission of harmful intermediates.
关键词： air purification,composite,adsorption,microporous material,porous glass,photocatalyst,TiO2
更新于2025-11-19 16:51:07
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Black phosphorous sensitized TiO <sub/>2</sub> mesocrystals photocatalyst for hydrogen evolution with visible and near-infrared light irradiation
摘要： Wide absorption from ultraviolet (UV) to near-infrared (NIR) region and enhanced charge separation are two main requirements for promising semiconductor photocatalysts. Here, we studied visible-NIR driven photocatalytic hydrogen evolution over black phosphorus nanosheets/TiO2 mesocrystals loaded with Pt heterostructure (BP NS/ Pt (3 wt%)/TMC TMC). BP NS/Pt (3 wt%)/TMC can harvest photons from UV to NIR and simultaneously has enhanced charge separation to increase the generation of electrons for photocatalytic reduction of water. BP NS/Pt (3 wt%)/TMC exhibited photocatalytic H2 evolution rates of 1.9 and 0.41 μmol h-1 under visible (λ> 420 nm (420-1800 nm)) and NIR (λ> 780 nm (780-1800 nm) irradiation, respectively, compared with 0.3 and 0.10 μmol h-1 for BP NS/Pt (3 wt%)/P25. Moreover, a comparative study was made to examine the effect of thickness of BP NS on the photocatalytic H2 evolution. Femtosecond time-resolved diffused reflectance spectroscopy (fs-TRDRS) was integrated together with photoelectrochemical measurement to shed the light on the importance of charge transfer and separation, confirming that decreasing the thickness of BP NS enhances electron injection from BP NS to TMC to increase the photocatalytic activity.
关键词： hydrogen evolution,Black phosphorus,visible-light photocatalyst,charge carriers dynamics,TiO2 mesocrystals,femtosecond time-resolved diffuse reflectance
更新于2025-11-19 16:51:07
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Deposition of TiO <sub/>2</sub> photocatalyst on polyethylene terephthalate or polyimide polymer films by reactive sputtering for flexible photocatalytic sheets
摘要： Polycrystalline anatase TiO2 films were deposited by rf reactive magnetron sputtering on polyethylene terephthalate (PET) or polyimide (PI) films with different buffer layers, such as SiO2 or Zn2SnOx (ZTO) between the TiO2 film and the substrate. Such TiO2/(SiO2 or ZTO)/(PET or PI) sheets with high transmittance in the visible region of light performed high photo-decomposition ability of CH3CHO under the UV irradiation of the black light centered at 352 nm. In the case of using SiO2 as the buffer layer, “nano-pore layer” was observed clearly in full area of the polymer substrates close to the buffer layers after the UV irradiation, whereas such degradation was suppressed drastically in the case of using ZTO as the buffer layer. Such photocatalytic sheets performed also photo-induced hydrophilicity by the UV irradiation, where the contact angle to pure water became around 5O under the UV irradiation. After additional deposition of SiO2 by the reactive sputtering under rather high total gas pressure of 3.0 Pa on the outermost surface of the TiO2 films, the photo-induced hydrophilicity was maintained for more than 98 days in the dark. Such 3-layerd SiO2/TiO2/ZTO on PET or PI substrates should be the promising flexible photocatalytic sheets with the retentional photo-induced hydrophilicity.
关键词： PET,TiO2,Photocatalyst,PI,Reactive Sputtering,Flexible substrate
更新于2025-11-19 16:51:07
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Ethanol sensing properties and reduced sensor resistance using porous Nb2O5-TiO2 n-n junction nanofibers
摘要： One-dimensional (1D) and porous Nb2O5-TiO2 n-n junction nanofibers with different Nb molar ratios have been synthesized by a simple electrospinning approach. A decrease in the average grain size and consequently an increase in the specific surface area were observed due to the introduction of Nb2O5 into TiO2 nanofibers. In comparison with pure TiO2 nanofibers, the Nb2O5-TiO2 nanofibers exhibited improved ethanol sensing response and a reduction in electrical resistance. The optimum operation temperature was reduced from 300 °C for pure TiO2 to 250 °C for Nb2O5-TiO2. The best sensing property was found for Nb2O5-TiO2 with 6 mol% Nb2O5, showing the highest response of 21.64–500 ppm ethanol at 250 °C, which was 2.79 times as high as that of pure TiO2 nanofibers at 300 °C. The reduction of Nb2O5-TiO2 based sensor resistance was attributed to the substitution of Ti4+ by Nb5+ ions and the formation of n-n junctions between Nb2O5 nanoparticles and TiO2 nanoparticles. The enhancement sensing mechanism of Nb2O5-TiO2 nanofibers was mainly ascribed to the enhanced resistance modulation owing to the substitution of Ti4+ by Nb5+ ions, formation of n-n junctions, and high surface area as well as small grain size of Nb2O5-TiO2 nanofibers.
关键词： Gas sensor,n-n junctions,Electrospinning,Nb2O5,TiO2
更新于2025-11-14 17:15:25
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Platinum-enhanced amorphous TiO2-filled mesoporous TiO2 crystals for the photocatalytic mineralization of tetracycline hydrochloride
摘要： The adsorption ability and photoactivity of a photocatalyst largely determine the mineralization efficiency of antibiotics. Herein, aiming to enhance the adsorption and mineralization of antibiotics, we constructed a hierarchical porous core-shell structure by filling amorphous TiO2 in the pores of Pt-doped mesoporous TiO2 crystals (MCs). The physical–chemical properties of the prepared samples were investigated by surface photovoltage spectroscopy, X-ray photoelectron spectroscope, etc. Adsorption and photocatalysis experiments were conducted with tetracycline hydrochloride as the model antibiotic. Pt nanoparticles doped at the interface of the rutile-amorphous homojunction remarkably enhanced the built-in electric field. The enhanced electric field increased the hole transfer to the catalyst surface, and the Pt doping treatment promoted the growth of amorphous TiO2 into the mesopores of the MCs. The optimization increased the surface area of the catalyst without increasing the thickness of the amorphous TiO2 shell, thereby reducing the charge migration distance from the core–shell interface to the catalyst surface. The adsorption amount and mineralization efficiency of tetracycline hydrochloride for the porous core-shell composite were 6.7 and 3.8 times of those for MCs, respectively.
关键词： Crystal,Amorphous TiO2,TCH,Mesoporous TiO2,SPV,Charge carriers
更新于2025-11-14 17:04:02