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Surface defect and rational design of TiO2?x nanobelts/ g-C3N4 nanosheets/ CdS quantum dots?hierarchical structure for enhanced visible-light-driven photocatalysis
摘要： TiO2-x/g-C3N4/CdS ternary heterojunctions are fabricated through thermal polymerization-chemical bath deposition combined with in-situ solid-state chemical reduction approach. The prepared materials are characterized by X-ray diffraction, Fourier transform infrared spectra, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption, and X-ray photoelectron spectroscopy. The results show that the ternary heterojunctions are formed successfully and CdS quantum dots (QDs) and TiO2 are anchored on surface of g-C3N4 nanosheets simultaneously. The visible-light-driven photocatalytic degradation ratio of Bisphenol A and hydrogen production rate are up to 95% and ~254.8 mmol h-1, respectively, which are several times higher than that of pristine TiO2. The excellent visible-light-driven photocatalytic activity can be ascribed to the synergistic effect of TiO2-x, g-C3N4 and CdS QDs which extend the photoresponse to visible light region and favor the spatial separation of photogenerated charge carriers.
关键词： Photocatalysis,Ti3+ self-doping,g-C3N4 nanosheets,CdS quantum dots,TiO2 nanobelts
更新于2025-09-04 15:30:14
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Graphene oxide enwrapped polyimide composites with efficient photocatalytic activity for 2,4-dichlorophenol degradation under visible light irradiation
摘要： In this study, graphene oxide (GO) enwrapped polyimide (PI) composite photocatalyst was prepared via a facile ultrasonic chemical method. The as-synthesized GO/PI hybrid composite can serve as a stable metal-free photocatalyst for 2,4-dichlorophenol (2,4-DCP) degradation under visible-light irradiation. After loading of GO, the GO/PI composites displayed enhanced photocatalytic performance. The apparent rate constant for 2,4-DCP degradation of the composites was approximately 4.5 times as high as that of bare PI. The results of radical trapping experiments and electron spin resonance indicated that the photogenerated hole (h+) and O2? were the main responsible for the 2,4-DCP degradation. The energy band diagram derived from Mott-Schottky and UV–vis diffuse absorption spectra revealed that the formed heterojunction between PI and GO is type-II. The formed heterojunction with well matched energy levels leads to an efficient injection of photoinduced electrons from PI to GO, and facilitates the separation of photoinduced charge carrier. The combined transient photocurrent and electrochemical impedance spectroscopy results further verified the enhancement was mainly ascribed to the improved charge carrier separation performance of composite.
关键词： Photocatalysis,2,4-dichlorophenol,Heterojuction,Polyimide,GO
更新于2025-09-04 15:30:14
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Effects of Operating Parameters on Photocatalytic Degradation of Methylene Blue or Phenol on Supported Titanium-Based Catalysts
摘要： Photocatalytic decompositions of both methylene blue and phenol in aqueous solutions were conducted separately on titanium-based catalysts. The catalysts were prepared using impregnation method on different supports (SiO2, Al2O3 or ZSM-5) and titanium precursors (TiO2 or TiCl4). They were tested in visible light or UV irradiations of different wavelengths (254 and 365 nm). The physico-chemical characteristics of the catalysts were obtained using BET, XRD, FTIR and TGA. The supports surface areas and porosities showed insignificant decreased after impregnation with the active components. The diffraction patterns showed strong peaks that are assigned to titania anatase phase and weaker peak that indicated low concentration of rutile phase. Irrespective of the support, FTIR showed broad peaks of Ti-O-Ti linkages in TiO2 particles. The catalysts were found to be active in decomposition of either methylene blue or phenol from aqueous solutions. For both methylene blue and phenol, the removal trend is TiO2/SiO2<TiO2/Al2O3<<TiO2/ZSM-5.
关键词： Titania,Phenol,Precursors,Methylene blue,Supports,Photocatalysis
更新于2025-09-04 15:30:14
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Electronic Tuning of Metal Nanoparticles for Highly Efficient Photocatalytic Hydrogen Peroxide Production
摘要： We here present an innovative approach to increase the electron density of metallic Pd nanoparticles loaded on TiO2 photocatalysts by coordinating Pd with surface-anchored organic ligands. X-ray photoelectron spectroscopy and X-ray absorption near edge structure measurements confirm the negative charge on the Pd nanoparticle induced by electron donation from amine groups of the ligands. The electronically modified Pd on TiO2 exhibits unprecedentedly high photocatalytic H2O2 production from O2 reduction. Mechanistic investigations suggest that the enhanced performance results from electronic tuning of Pd nanoparticles, leading to enhanced charge separation on TiO2 support, improved activity of Pd nanoparticles as an oxygen reduction center, and improved selectivity for O2 reduction to produce H2O2.
关键词： immobilized organic ligands,oxygen reduction reaction,electronic tuning,hydrogen peroxide,photocatalysis
更新于2025-09-04 15:30:14
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Facile Synthesis of Visible Light-Induced g-C3N4/Rectorite Composite for Efficient Photodegradation of Ciprofloxacin
摘要： A novel kind of g-C3N4/rectorite composite with high visible-light photoactivity was developed via a mild and cost effective two-step process. Cipro?oxacin (CIP), a typical antibiotic, was applied to evaluate the photoactivity of the received catalysts. Furthermore, the by-products of CIP photodegradation were analyzed and the possible degradation pathways were also discussed. Compared with bare photocatalysts, the received composite possessed well reusability and higher photoactivity towards CIP. According to the characterization analysis results, layered g-C3N4 was successfully immobilized on layered rectorite, which could not only promote its adsorption capacity but also provide more reactive sites for CIP adsorption and photodegradation. Compared with bare g-C3N4, the photoactivity of the prepared composite was signi?cantly enhanced. The enhancement should be mainly due to the lower recombination rate of photogenerated carriers and the improved adsorption capacity toward CIP. This study demonstrated that the obtained g-C3N4/rectorite composite should be a promising alternative material in wastewater treatment.
关键词： rectorite,wastewater treatment,photocatalysis,cipro?oxacin,g-C3N4
更新于2025-09-04 15:30:14
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Ethiopian natural zeolites for photocatalysis
摘要： The combination of zeolites and photochemistry has recently shown excellent results due to the special structure of the zeolites that helps a better use of the solar energy improving the selectivity of the chemical reactions carried out. There are several reports on the preparation of TiO2 confined nanoparticles in synthetic zeolites. However, very few reports are found on the use of natural zeolites. Zeolites are a vast natural resource in Ethiopia that remains unexploited. Their microporous structure can accommodate a wide variety of cations such as sodium, potassium and magnesium among others. The main objective of our work was to test the potential use of the naturally occurring zeolites, with high content in titanium, as photocatalysts. The samples have been characterized by X-ray diffraction (XRD), chemical analysis (ICP-OES), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (UV-Vis) and photocatalytic activities of the samples were tested in photocatalytic degradation of methyl orange (MO).
关键词： Natural zeolite,Photocatalysis,Methyl orange,Band gap energy,TiO2 loading
更新于2025-09-04 15:30:14
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Photoelectrochemically Active N‐Adsorbing Ultrathin TiO <sub/>2</sub> Layers for Water‐Splitting Applications Prepared by Pyrolysis of Oleic Acid on Iron Oxide Nanoparticle Surfaces under Nitrogen Environment
摘要： Highly performing photocatalytic surfaces are nowadays highly desirable in energy fields, mainly due to their applicability as photo water-splitting electrodes. One of the current challenges in this field is the production of highly controllable and efficient photoactive surfaces on many substrates. Atomic layer deposition has allowed the deposition of photoactive TiO2 layers over wide range of materials and surfaces. However, nitrogen doping of the growing layers, a highly effective way of controlling the absorption edges of photoactive surfaced, is still a challenging task. Here, the preparation of hierarchical nanostructured surfaces based on Langmuir–Schaefer and atomic layer deposition is proposed. Ultrathin TiO2 layers that are photoelectrochemically active in water splitting are prepared by a relatively low-temperature catalytic decomposition of oleic acid capping layers of iron oxide nanoparticles and the posterior nitrogen adsorption. The results evidence that simple N-adsorption is sufficient to narrow the bandgap of TiO2 layers that is equal to bandgap narrowing (0.12 eV) observed for substitutionally N-doped materials. The photocatalytic activity tests of the prepared surfaces in water-splitting applications demonstrate ≈90% increase in the activity of the N-adsorbing TiO2 layers.
关键词： Langmuir–Schaefer,magnetite (Fe3O4),photocatalysis,titanium dioxide (TiO2),atomic layer deposition (ALD)
更新于2025-09-04 15:30:14
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Bimetallic metal organic frameworks: Magnetically separable heterogeneous catalyst for efficient organic transformation and photocatalytic dye degradation
摘要： A new bimetallic MOF (BMOF) has been synthesized using iron and zinc as inorganic metal nodes and 1-4, benzenedicarboxylic acid (BDC) as organic linker molecule. BMOF was confirmed with Single crystal X-ray diffraction (SCXRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy-high angle annular dark-field imaging (TEM-HAADF), Field emission scanning electron microscopy-energy dispersive x-ray analysis (FESEM-EDX), Vibrating sample magnetometer (VSM) and inductively coupled plasma-mass spectrometry (ICP-MS) analysis. The synthesized BMOF shows excellent optical and magnetic properties. BMOF acts as a heterogeneous catalyst and show high catalytic activity towards bis(indolyl)methane synthesis and photocatalytic degradation of methylene blue (MB) under visible light illumination.
关键词： Metal-organic frameworks,dye degradation,Bis(indolyl)methanes,photocatalysis
更新于2025-09-04 15:30:14
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Hydroxy-carbonate-assisted synthesis of high porous graphitic carbon nitride with broken of hydrogen bonds as a highly efficient visible-light-driven photocatalyst
摘要： Graphite carbon nitride (g-C3N4) is a promising candidate as an efficient, affordable, and sustainable alternative photocatalyst owing to its unique physical and chemical properties. However, the photocatalytic activity of pristine g-C3N4 is still far below what is expected, because of its insufficient active site and high electron-hole recombination rates. Herein, we develop a novel strategy ― a one-step hydroxy-carbonate-assisted route ― to try to overcome these disadvantages in g-C3N4 nanosheets by creating substantial pores ranging from mesoporous to macropore, which are mainly caused by the partial breaking of hydrogen bonds and removing of magnesium oxide. Luxuriant pores in g-C3N4 not only serve as a reaction center by providing a large number of active sites at pore edges, but also effectively improve the photogenerated carrier separation by shortening their transfer lengths. The highly efficient visible-light photocatalytic activity of porous g-C3N4 nanosheets are demonstrated by degrading methyl blue (MB) and gentian violet (GV) as models, which its degradation rate constant is respectively more than 109 times and 12 times higher than those of pristine g-C3N4. Meanwhile, the high porous g-C3N4 has robust stability. The simple and effective strategy proposed here provides a direct route to highly functionalized g-C3N4 nanosheets and other layered semiconductors for various applications.
关键词： transfer of electrons,one-step route,high porous g-C3N4,hydroxy-carbonate-assisted route,photocatalysis
更新于2025-09-04 15:30:14
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Optimization of photocatalytic degradation of dye?wastewater?by CuFe<sub>2</sub>O<sub>4</sub>/AgBr composite using response surface methodology
摘要： In this paper, a simple response surface methodology (RSM) based on central composite design (CCD) was applied to determine the optimum processing parameters of photocatalytic degradation of acid red 88 (AR88) by CuFe2O4/AgBr composites. The effect of CuFe2O4 loading, initial concentration of pollutant, and photocatalyst concentration on the yield of AR88 degradation rate was investigated. Based on the statistical experimental design, the maximum degradation rate of 94.7% was achieved under optimal conditions: the 34.69% of CuFe2O4 loading, 16.34mg/L of intial concentration of AR88, 1.51g/L of photocatalyst concentration. The kinetics exploration indicated that the degradation process fitted pseudo-first order kinetic model. What’t more, the trapping experiment of active species demonstrated that ·O2- and ·OH were the dominant species.
关键词： CuFe2O4/AgBr composites,response surface methodology,central composite design,acid red 88,photocatalysis
更新于2025-09-04 15:30:14