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Ag/αFe2O3-rGO novel ternary nanocomposites: synthesis, characterization, and photocatalytic activity
摘要： In this research, novel ternary Ag/αFe2O3-rGO nanocomposites with various contents of GO were synthesized via a facile one-pot hydrothermal method. Ag/αFe2O3-rGO nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrometer (EDX), photoluminescence (PL) spectroscopy, and Fourier transform infrared (FTIR). The results showed that hematite nanoparticles and Ag nanoparticles were well decorated on the graphene surface. Photocatalytic activity of Ag/αFe2O3-rGO ternary nanocomposites and pure Ag/αFe2O3 was investigated for photodegradation of Congo red dye solution as a model pollutant under UV light irradiation. The ternary nanocomposite with 1.8 mg/ml GO aqueous solution concentration shows higher degradation efficiency under UV light irradiation than the pure Ag/αFe2O3 and the nanocomposites with other GO aqueous solution concentrations. It was observed that the adsorption of the dyes on the nanocomposites surface is dependent on the graphene content due to a decrease in the recombination rate, particles size, and increase charge carrier transfer. The results show that the Ag/αFe2O3-rGO nanocomposite can be used as an excellent photocatalytic material for degradation of Congo red dye in wastewater. A possible photocatalytic mechanism was proposed for degradation of Congo red dye.
关键词： ternary nanocomposites,photocatalytic activity,graphene,Ag/αFe2O3-rGO
更新于2025-09-23 15:21:01
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Enhanced photocatalytic activity of g-C3N4 quantum dots/Bi3.64Mo0.36O6.55 nanospheres composites
摘要： In this research, heterostructured g-C3N4 quantum dots (CNQDs)/Bi3.64Mo0.36O6.55 nanospheres have been fabricated trough an in situ precipitation process. Compared to the pure Bi3.64Mo0.36O6.55, the as-fabricated CNQDs/Bi3.64Mo0.36O6.55 nanocomposites exhibited significantly improved photocatalytic performance for the photodegradation of rhodamine B (Rh B) and bisphenol A (BPA). In addition, 5 wt% CNQDs/Bi3.64Mo0.36O6.55 sample showed the highest photocatalytic efficiency under visible-light irradiation (λ > 420 nm). The effective separation and transmission of photogenerated electron-hole pairs caused by CNQD loading as well as the improved BET surface area are associated with the enhancement of the photocatalytic activity of the CNQDs/Bi3.64Mo0.36O6.55 photocatalyst.
关键词： Water purification,Bi3.64Mo0.36O6.55 nanospheres,Binary heterostructure,g-C3N4 quantum Dots,Photocatalytic activity
更新于2025-09-23 15:21:01
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Type-II heterojunction constructed by Ag2S-coupled ZnO microspheres with visible light-responsive antibacterial activity
摘要： ZnO nanorods-assembled microspheres were photosensitized with a layer of low bandgap Ag2S nanoparticles on the branched nanorods to get a type-II core/shell heterojunction (ZnO@Ag2S). The heterojunction with unique band configuration exhibited better visible light-responsive antibacterial activity than pure ZnO, which is attributed to the inhibition of photocarrier recombination and efficient charge separation and transfer. Scavenger test confirmed that the photoinactivation of bacteria was directed by the (cid:1) radicals and photogenerated holes. The growth of Gram-negative bacteria was more effectively restrained by ZnO@Ag2S than that of Gram-positive bacteria and fungi because of structural difference of cell walls.
关键词： ZnO@Ag2S,Composite materials,Mechanism,Semiconductors,Photocatalytic activity
更新于2025-09-23 15:21:01
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Enhanced photocatalytic activity based on TiO <sub/>2</sub> hollow hierarchical microspheres/reduced graphene hybrid
摘要： A novel TiO2 hollow hierarchical microspheres/reduced graphene oxide (TiO2 HHMs/rGO) hybrid was prepared by a facile and efficient two-step solvothermal synthesis method. The TiO2 HHMs with the size ～500 nm were uniformly distributed on the surface of rGO nanosheets. The as-prepared TiO2 HHMs/rGO hybrid is stable and exhibits a significantly higher photocatalytic activity (97.8%) for 40 ml of 10 mg/Rhodamine B (RhB) solution than that of the pure TiO2 microspheres (75.2%) and Degussa P25 (53.6%). The rGO nanosheet acts as a microelectrode for rapid accepting and separating the photogenerated electron on surface, which effectively slow the recombination rate of electrons and holes, and then effectively enhance the photocatalytic activity of the hybrid. The as-prepared novel TiO2 HHMs/rGO hybrid shows great promising for practical photocatalytic applications.
关键词： TiO2 hollow hierarchical microspheres/reduced graphene oxide (TiO2 HHMs/rGO) hybrid,enhancement,photocatalytic activity,two-step solvothermal synthesis
更新于2025-09-23 15:21:01
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{0 0 1}-Facet-Exposed Ag <sub/>4</sub> V <sub/>2</sub> O <sub/>7</sub> Nanoplates: Additive-Free Hydrothermal Synthesis and Enhanced Photocatalytic Activity
摘要： The synthesis of silver pyrovanadate, Ag4V2O7, nanoplates with exposed {0 0 1}-facets by a facile, additive-free hydrothermal method was described in this paper. The photocatalytic activity of rhodamine B over Ag4V2O7 samples under solar light irradiation was also evaluated. By using an equimolar mixture of NH4VO3 and AgNO3 with the presence of a suitable amount of ammonia, Ag4V2O7 nanoplates were obtained readily and purely at temperatures from 100 to 140°C for 4 h. The c-axis orientation growth of Ag4V2O7 nanoplates occurred and increased monotonously with temperatures in the range of over 100 up to 140°C. Further increase in hydrothermal temperature up to 220°C, the Ag4V2O7 phase no longer existed and the β-AgVO3 phase was formed instead. The photocatalytic activity of the optimized Ag4V2O7 sample comprising {0 0 1}-facet-exposed nanoplates with the highest degree of orientation was significantly higher than that of the random-oriented sample. The effects of using ammonia as a complexing agent on the structure, microstructure, texture, exposed facet, and photocatalytic activity of Ag4V2O7 samples were also investigated for the first time.
关键词： photocatalytic activity,hydrothermal synthesis,Ag4V2O7,rhodamine B,nanoplates,solar light irradiation
更新于2025-09-23 15:21:01
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PHOTOCATALYTIC REMOVAL OF PHENOL OVER MESOPOROUS ZnO/TiO2 COMPOSITES
摘要： A series of mesoporous ZnO/TiO2 composites were successfully synthesized using cetyltrimethylammonium bromide surfactant. The composites of different Zn:Ti molar ratios (0.5:1, 0.75:1, and 1:1) were prepared by impregnating ZnO onto mesoporous TiO2. XRD results verified co-existence of both anatase TiO2 and hexagonal wurtzite ZnO in the ZnO/TiO2 composites. Based on the Tauc plots, all the composites showed almost the same band gap energy of approximately 3.21 eV. The fourier transform infrared spectroscopy results successful covering of ZnO on the surface of the TiO2 as the hydrophilicity property of TiO2 decreased remarkably with the loading of ZnO in the composites. N2 adsorption-desorption isotherms of the samples exhibited type-IV isotherm with a hysteresis loop. The Barrett-Joyner-Halenda pore size distribution revealed that the average pore size of the composites was around 3.6 nm, indicating the formation of mesopores dominantly in the samples. The photocatalytic removal of phenol over the samples under UV light irradiation after 3 h decreased in the order: ZnO/TiO2 composites > anatase TiO2 (with surfactant) > anatase TiO2 (without surfactant) > ZnO. The composite with Zn:Ti molar ratio of 0.75:1 has achieved the highest photocatalytic activity of 36.5% in the removal of phenol under UV light irradiation for 3 h.
关键词： photocatalytic activity,ZnO/TiO2 composites,phenol,ZnO,TiO2
更新于2025-09-23 15:21:01
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In situ fluorine doped ZrO2?x nanotubes for efficient visible light photocatalytic activity
摘要： The F-doped ZrO2?x nanotubes are synthesized by anodic oxidization in a F-containing electrolyte and following a low temperature annealing process. The F-doped ZrO2?x nanotubes exhibit a dramatic increase in visible light absorption and efficient visible light photocatalytic activity which are not possessed to normalized ZrO2. The fluorine in anodic ZrO2 nanotubes plays a vital role in the formation of abundant anion vacancies during the annealing. Combining the doping effect of the residual fluorine element, the band gap of the F-doped ZrO2?x nanotubes reduced from 5.13 to 2.35 eV. Moreover, the transient photocurrent response plots and the photocatalytic experiments reveal the highly effective electrons–holes separation of the F-doped ZrO2?x nanotubes and enhanced visible-light photocatalytic degradation for RhB. The degradation rate of RhB in the presence of the F-doped ZrO2?x nanotubes catalyst has reached up to 83% under 2 h low-power LED light irradiation. In addition, the possible photocatalytic mechanism of the F-doped ZrO2?x nanotubes has been proposed via studying the band structure. It is believed that the F-doped ZrO2?x nanotubes will have a bright future for sustainable energy sources and cleaning environment.
关键词： oxygen vacancies,F-doped ZrO2?x nanotubes,anodic oxidization,visible light photocatalytic activity,band gap narrowing
更新于2025-09-23 15:21:01
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Tuning the Optical Band Gap of Pure TiO2 via Photon Induced Method
摘要： Titanium dioxide, a well known photocatalyst will become more useful if it utilizes visible light. Many efforts have been made to achieve the utilization of visible light by TiO2 for photocatalytic activity by changing the preparation methods or by doping various transition metals. Herein, a novel Photon Induced Method (PIM) is being proposed to produce oxygen-rich TiO2 with modified optical band gap and high stability. The prepared TiO2 nanoparticles have been subjected to various characterizations such as XRD, HRSEM, HRTEM, FTIR, UV-Vis and PL. XRD results reveal that as the calcination temperature is increased, the crystallite size of the TiO2 nanoparticles is seen to increase. Also, the XRD results reveal an increase in pure anatase phase stability upto 750°C when compared to earlier reports of pure anatase phase stability upto 650°C. HRTEM analysis shows the formation of nanosized bullet like structure. A narrowing of optical band gap to 3.09 eV is evident through UV-Vis absorption studies. This tuning of band gap is expected to facilitate the absorption of visible light. The photocatalytic activity of the prepared TiO2 nanoparticles has also been studied. The results reveal that TiO2 nanoparticles prepared by this novel method exhibit an increased photocatalytic activity when compared to the standard Degussa P25 sample reported earlier.
关键词： Pure TiO2 nanoparticles,Optical bandgap,Photocatalytic activity,Visible light
更新于2025-09-23 15:21:01
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Graphene films decorated with TiO2 grown by atomic layer deposition: characterization and photocatalytic activity study under UV-visible light
摘要： The great potential of graphene can be enhanced thanks to the functionalization of its surface. For this aim, different thicknesses of TiO2 were grown on graphene films by atomic layer deposition (ALD) at 200 °C using H2O and TiCl4 as precursors. The changes in electronic structure of graphene after the deposition of TiO2 and the influence of graphene in TiO2 photocatalytic activity under UV-Visible irradiation were studied. Results indicated the presence of inhomogeneity and intrinsic strain effects within the same sample. Undecorated graphene showed pre-existent strain due to the mismatch between graphene film and the underlying substrate, while non-intentional self-doping is caused by the presence of charged impurities. The deposition of TiO2 films with thickness ≤10 nm led graphene to be p-doped, while strain became the dominant effect increasing film thickness. Oxygen vacancies in the film decreased exponentially by increasing the film thickness leading to a stoichiometric O/Ti atomic ratio of TiO2 above 10 nm thickness. The combination of TiO2 and graphene enhanced the efficiency of electron-hole separation of TiO2 under UV-Visible light, leading to a higher photocatalytic activity tested for methyl red molecule degradation, making TiO2/Graphene hybrid material a promising candidate for the photodegradation of pollutants and water purification.
关键词： Atomic Layer Deposition,Graphene,Photocatalytic Activity,TiO2,UV-Visible Light
更新于2025-09-23 15:21:01
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Enhanced Photocatalytic Activity of 2 <i>H</i> -MoSe <sub/>2</sub> by 3 <i>d</i> Transition Metal Doping
摘要： To develop MoSe2-based photocatalysts, increasing the catalytic activity of 2H-MoSe2 is essential. In this work, the electronic and photocatalytic properties of 3d transition metal (TM) doped (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) 2H-MoSe2 were investigated by first-principles calculations. The results indicate that Sc, Ti, V, Cr, Mn, Fe and Co atoms tend to substitute the Mo atoms under Se-rich condition, while Ni, Cu and Zn atoms prefer to occupy the interstitial positions. More importantly, Sc- and Ti-doped 2H-MoSe2 can enhance the photocatalytic activity by increasing the oxidizability of photogenerated holes, suppressing the recombination of photogenerated carriers and increasing the number of catalytic active sites.
关键词： photocatalytic activity,2H-MoSe2,3d transition metal doping,electronic properties,first-principles calculations
更新于2025-09-23 15:21:01