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Mechanisim investigation on the enhanced and selective photoelectrochemical oxidation of atrazine on molecular imprinted mesoporous TiO2
摘要： In this work, enhanced and selective photoelectrochemical (PEC) oxidation of atrazine was realized on molecular imprinted mesoporous TiO2 (MI-meso-TiO2). The investigation revealed that, for one hand, the surface MI sites could function as surface defects for accelerating the separation of photogenerated holes and electrons, leading to enhanced generation of hydroxyl radicals. For the other hand, the MI sites showed enhanced binding affinity toward atrazine, resulted from the formation of multiple hydrogen bonds and halogen bonds etc., which was testified by in situ ATR-FTIR spectra. It led to the enhanced adsorption and improved local concentration of atrazine on the electrode surface. Both the two factors contributed to the improved PEC oxidation activity for atrazine on MI-meso-TiO2 compared with that on meso-TiO2. Moreover, the high binding affinity between MI sites and atrazine resulted in the selective recognition ability toward atrazine in the presence of the coexisting pollutants, so that selective PEC oxidation of atrazine in complex polluted water samples was successfully achieved on MI-meso-TiO2 with the apparent rate constant of 0.25 h-1, whereas that on meso-TiO2 was only 0.08 h-1. This work provided something new for explaining the selective and enhanced PEC performance on molecular imprinting catalyst.
关键词： mesoporous TiO2,molecular imprint,selective photoelectrochemical oxidation,atrazine
更新于2025-09-23 15:22:29
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2D/2D/2D heterojunction of Ti3C2 MXene/MoS2 nanosheets/TiO2 nanosheets with exposed (001) facets toward enhanced photocatalytic hydrogen production activity
摘要： Exposing the highly active facets and hybridizing the photocatalyst with appropriate cocatalysts with right placement have been regarded as a powerful approach to high performance photocatalysts. Herein, TiO2 nanosheets (NSs) are in situ grown on highly conductive Ti3C2 MXene and then MoS2 NSs are deposited on the (101) facets of TiO2 NSs with mainly exposed high-active (001) facets through a two-step hydrothermal method. And a unique 2D-2D-2D structure of Ti3C2@TiO2@MoS2 composite is achieved. With an optimized MoS2 loading amounts (15 wt%), the Ti3C2@TiO2@MoS2 composite shows a remarkable enhancement in the photocatalytic H2 evolution reaction compared with Ti3C2@TiO2 composite and TiO2 NS. It also shows good stability under the reaction condition. This arises from: (i) the in situ growth of TiO2 NSs construct strong interfacial contact with excellent electronic conductivity of Ti3C2, which facilitates the separation of carriers; (ii) the coexposed (101) and (001) facets can form a surface heterojunction within single TiO2 NS, which is beneficial for the transfer and separation of charge carriers; and (iii) the MoS2 NSs are deposited on the electrons-rich (101) facets of TiO2 NSs, which not only effectively reduces the charge carriers recombination rate by capturing photoelectrons, but also makes TiO2 NSs expose more highly active (001) facets to afford high-efficiency photogeneration of electron-hole pairs.
关键词： Exposed active facet,Ti3C2 MXene,TiO2 nanosheets,Photocatalytic H2 production,MoS2 nanosheets
更新于2025-09-23 15:22:29
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Noble-metal-free MOF derived hollow CdS/TiO2 decorated with NiS cocatalyst for efficient photocatalytic hydrogen evolution
摘要： Noble-metal-free hollow NiS/CdS/TiO2 (NS/CT) nanohybrid photocatalyst was prepared by a facile hydrolysis combining sulfidation process using metal-organic framework (MOF) as a template. The as-prepared composites were characterized by SEM, TEM, XRD, XPS, UV-vis, and photoelectrochemical techniques. It is found that NS/CT composites with porous hollow structure show significantly enhanced photocatalytic efficiency compare to TiO2, or CdS/TiO2, or even Pt decorated CdS/TiO2 photocatalysts, for hydrogen evolution from water upon visible light irradiation. Significantly, NS/CT composite with optimum amount of 30% CdS and 0.3% NiS exhibits the highest photoactivity, with H2 production rate of 2149.15 μmol·g-1·h-1, which is 23.9 and 2.3 times higher than that of the pure CdS particles and the CdS/TiO2 nanocomposites, respectively. The superiority of the composites arises from the synergistic effect of the heterojunction for rapid charge separation and the NiS cocatalyst for accelerated surface redox reaction.
关键词： NiS cocatalyst,H2 production,CdS/h-TiO2,heterojunction,photocatalysis.
更新于2025-09-23 15:22:29
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Antioxidant functionalized silica-coated TiO2 nanorods to enhance the thermal and photo stability of Polypropylene
摘要： Rutile TiO2 is commonly used as UV shielding agent because of the absorption of UV light. In this research, we integrated the function of rutile TiO2 nanoparticles and antioxidants (AO), and prepared a kind of multifunctional TiO2 nanoparticles with the capacity of both UV absorption and antioxidation. Firstly, rutile TiO2 nanorods were prepared and encapsulated by SiO2 to decrease its photocatalytic activity. Then, antioxidant functionalized silica-coated TiO2 nanorods (AO-KH550-SiO2-TiO2) were successfully synthesized by using aminosilane coupling agent (KH550) as a bridge. By melt blending method, AO-KH550-SiO2-TiO2 were incorporated into PP matrix. The results indicated that AO-KH550-SiO2-TiO2 could improve both photo stability and thermal stability of PP. PP/AO-KH550-SiO2-TiO2 film broke after 220 h UV irradiation, and the broken time of PP/TiO2 film was only 80 h. And the oxidation induction time of PP/AO-KH550-SiO2-TiO2 sample was 4.7 min, while PP/TiO2 sample showed no antioxidation effect. In addition, AO-KH550-SiO2-TiO2 exhibited excellent anti-extraction property. This novel design of AO-KH550-SiO2-TiO2 may open up a new avenue for fabricating multifunctional nanoparticles and facilitating their practical application.
关键词： TiO2,antiaging,PP,antioxidant,SiO2
更新于2025-09-23 15:22:29
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Ion beam engineering of morphological, structural, optical and photocatalytic properties of Ag-TiO2-PVA nanocomposite thin film
摘要： Development of plasmonic nanocomposite coatings with tunable optical and photocatalytic properties is important for diverse technological applications. In this paper, we report modifications in the microstructural, optical and photocatalytic properties of Ag-TiO2-PVA nanocomposite thin film by 8 MeV Si3+ ion irradiation. Ag-TiO2-PVA nanocomposite thin films on silica glass were prepared by a combination of sol-gel method and spin coating. Ion irradiation induced morphological evolution of Ag-TiO2-PVA thin film was studied by atomic force microscopy and field emission scanning electron microscopy, which revealed interesting changes in the size distribution of nanostructures with increasing ion fluence. Ion irradiation of the Ag-TiO2-PVA thin film resulted in the emergence of SPR peak of Ag nanoparticles at 456 nm, which shifted to 446 nm along with enhancement in intensity as the ion fluence was increased. Significant enhancement in the photocatalytic efficiency of Ag-TiO2-PVA nanocomposite thin film for degradation of methylene blue was observed upon ion irradiation at 1 × 1013 ions/cm2. The origins of microstructural, morphological, optical and plasmonic modifications and enhancement in the photocatalytic efficiency of Ag-TiO2-PVA nanocomposite thin films have been discussed.
关键词： Ion irradiation,Surface plasmon resonance,Nanocomposite,Photocatalysis,Ag-TiO2-PVA
更新于2025-09-23 15:22:29
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Binary-phase TiO2 modified Bi2MoO6 crystal for effective removal of antibiotics under visible light illumination
摘要： A series of binary-phase TiO2 modified Bi2MoO6 nanocrystals have been prepared via a solvothermal-calcination process. Trace TiO2 modification can effectively enhance the visible light catalytic activity of Bi2MoO6 to remove the antibiotics in aqueous solution. The obtained TiO2/Bi2MoO6 composites were investigated by some physicochemical techniques like XRD, N2 adsorption, SEM, TEM, UV–vis DRS, Raman, XPS, PL and Photo-electrochemical measurement. The presence of TiO2 nanoparticles (NPs) influenced the crystal growth of Bi2MoO6, decreasing the crystal size of Bi2MoO6 and effectively promoting its specific surface area. Moreover, the conduction band of TiO2 can serve as the electron transfer platform, which largely boosts the effective separation of photocarriers at TiO2/Bi2MoO6 heterojunction interface. With optimal TiO2 content (0.41 wt%), TiO2/Bi2MoO6 exhibited the best photocatalytic performance for different antibiotics degradation, e.g. ciprofloxacin, tetracycline and oxytetracyline hydrochloride under visible light irradiation. Moreover, the mechanism for enhanced photocatalytic performance in ciprofloxacin degradation was illuminated.
关键词： Mechanism,Binary-phase TiO2,Antibiotics,Photocatalytic degradation,Bi2MoO6
更新于2025-09-23 15:22:29
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Enhanced Photocatalytic Hydrogen Evolution with TiO <sub/>2</sub> -TiN Nanoparticle Composites
摘要： Metal nitrides have potential in energy applications due to their physical and optical properties. Nanoparticle composites of titanium nitride (TiN) and titanium dioxide (TiO2) were investigated for their photocatalytic hydrogen (H2) activity via methanol reformation. Physical mixing of the nanoparticulate TiO2 and TiN was employed to prevent the oxy-nitride formation and particle aggregation observed in thermal preparations. This convenient combination of TiO2 and TiN demonstrated a substantial synergistic effect with enhanced activity (9.4 μmol/h TiO2-TiN vs 1.8 μmol/h TiO2) under combined UV/Vis light. Irradiation under only UV light resulted in a similar enhancement factor compared to using combined UV/Vis light, demonstrating that the enhanced activity of the composites occurs essentially for UV-driven photocatalysis. No activity/enhancement was observed with only visible light irradiation, however, minor enhancement was observed when switching between UV and UV/Vis irradiation, suggesting a contribution from the TiN plasmon. We propose that the plasmonic contribution is dependent on the band gap excitation of TiO2, which reduces the degree of band bending at the TiO2/TiN interface. This promotes the migration of hot electrons from TiN away from the TiO2/TiN interface to be used for H2 evolution.
关键词： TiO2-TiN Nanoparticle Composites,Plasmonics,Optical,Magnetic,and Hybrid Materials,Photocatalytic Hydrogen Evolution
更新于2025-09-23 15:22:29
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Image charge effect on the light emission of rutile TiO <sub/>2</sub> (110) induced by a scanning tunneling microscope
摘要： The plasmon-enhanced light emission of rutile TiO2(110) surface has been investigated by a low-temperature scanning tunneling microscope (STM). We found that the photon emission arises from the inelastic electron tunneling between the STM tip and the conduction band or defect states of TiO2(110). In contrast to the Au(111) surface, the maximum photon energy as a function of the bias voltage clearly deviates from the linear scaling behavior, suggesting the non-negligible effect of the STM tip on the band structure of TiO2. By performing differential conductance (dI/dV) measurements, it was revealed that such a deviation is not related to the tip-induced band bending, but is attributed to the image charge effect of the metal tip, which significantly shifts the band edges of the TiO2(110) towards the Femi level (EF) during the tunneling process. This work not only sheds new lights onto the understanding of plasmon-enhanced light emission of semiconductor surfaces, but also opens up a new avenue for engineering the plasmon-mediated interfacial charge transfer in molecular and semiconducting materials.
关键词： TiO2,scanning tunneling microscopy,light emission,plasmon
更新于2025-09-23 15:22:29
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Tuning electronic and optical properties of TiO<sub>2</sub> with Pt/Ag doping to a prospective photocatalyst: a first principles DFT study
摘要： Using first-principles density functional theory, the modulated electronic and optical properties of TiO2 with Pt/Ag substitutional dopants with varying concentration are investigated. Our calculations reveal the significant decreasing trend in the band gap of TiO2 while increasing the Pt (direct band gap) and Ag (indirect band gap) impurity concentration from 4.17% to 8.33% to 12.5%. The spin-polarized density of states reveal strong hybridization between the impurity bands with Ti-(3d) and O-(2p) bands near the Fermi level. The charge transfer mechanism depicts the delocalized electron cloud forming a strong bonding between the dopants (Pt/Ag) and oxygen of TiO2. Moreover, the absorption spectra of the Pt doped TiO2 structures have a broad peak at the visible range of energy spectrum with maximum absorption up to 0.7×10?5cm?1. The calculated reflectivity, energy loss function and extinction coefficient shows the enhanced optical properties of doped TiO2 compared to its pristine form. The obtained results predict the way to tailor the optical properties of Pt/Ag-doped TiO2 as an efficient photocatalyst in the visible region.
关键词： Pt,Optical properties,Electronic structure,Photocatalyst,Ag doped TiO2
更新于2025-09-23 15:22:29
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Development of titania-integrated silica cell walls of the titanium-resistant diatom, <i>Fistulifera solaris</i>
摘要： We report the biological synthesis of titania that is integrated into the silica-based cell walls of a titanium-resistant diatom, Fistulifera solaris. Titania is deposited across the diatom cell walls by simply incubating F. solaris in a culture medium containing a high concentration (2 mM) of a water-soluble organo-titanium compound, titanium(IV) bis(ammonium lactato) dihydroxide (TiBALDH) that would otherwise inhibit the growth of other diatom species. Furthermore, we genetically engineered the interfaces of the diatom cell walls with a titanium-associated peptide, which subsequently increased the Ti/Si atomic ratio by more than 50% (i.e., from 6.2 ± 0.2 % to 9.7 ± 0.5 %, as identified by inductively coupled plasma-atomic emission spectrometry). The titanium content on the F. solaris silica cell walls is one of the highest reported to date, and comparable to that of chemically synthesized TiO2-silica composites. Subsequent thermal annealing at 500°C in air converted the wall-bound titania to nanocrystalline anatase TiO2, a highly photocatalytically active phase. We propose that incubation of the titanium-resistant F. solaris with TiBALDH as demonstrated in this study could be a promising bioprocess towards the scalable synthesis of TiO2. In addition, the genetic engineering we used to modulate the surface properties of diatom silica cell walls could be extended to synthesize controlled nanomaterials for multiple applications including bioremediation, water purification, and energy conversion/storage.
关键词： Genetic engineering,silica cell wall,TiO2,Fistulifera solaris,diatom
更新于2025-09-23 15:21:21