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In situ decoration of g-C3N4 quantum dots on 1D branched TiO2 loaded with plasmonic Au nanoparticles and improved the photocatalytic hydrogen evolution activity
摘要： The hybrid 1D branched TiO2 loaded with surface plasmonic Au and decorated with g-C3N4 QDs were successfully fabricated which played a significant role in photocatalysis. The 1D branched TiO2 prepared by electrospinning followed by an alkali-hydrothermal process. The Au particles decorated by photo deposition and after that g-C3N4 QDs were grafted over it by a chemical vapor deposition method. The composite shows great improvement in photocatalytic hydrogen evolution and evolved about 2.22 mmol g?1 h?1 hydrogen. The composite sample has a quantum efficiency of 19.5% for hydrogen production at 420 nm light that depicts the performance behavior of the composite. The 1D branched TiO2 fiber facilitates the fast transfer of electrons and Au reduces the charge recombination due to its surface plasmonic effect while g-C3N4 QDs facilitate the visible light absorption by improving the optical properties and reduces the bandgap. The formation of the type II heterostructure system remarkably promotes the separation and transfer of electron holes and facilitates the photo-reduction reaction.
关键词： Quantum dots,Photocatalyst,Plasmonic,Hydrogen,Hierarchical
更新于2025-09-23 15:21:01
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Visible light assisted photocatalytic reduction of CO2 to ethane using CQDs/Cu2O nanocomposite photocatalyst
摘要： CO2 reduction through photocatalysis is considered a promising way to mitigate the abundance of this greenhouse gas in the earth’s atmosphere. In this work, blue-fluorescent carbon quantum dots (CQDs) were synthesized via a facile top-down hydrothermal method using biochar as the carbon source. The as-synthesized CQDs were incorporated together with commercial copper (I) oxide (Cu2O) nanoparticles to form CQDs/Cu2O nanocomposite. The CQDs, Cu2O and CQDs/Cu2O nanocomposite were then applied for gas phase photocatalytic reduction of CO2. The experiments were performed under visible light irradiation in a self-designated photoreactor which was connected to an online Gas Chromatography (GC). High resolution transmission electron microscopy (HRTEM) confirmed the uniform deposition of CQDs with size ranging from 2.5 to 6.0 nm on the surface of Cu2O nanoparticles. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy further revealed the presence of CQDs on the surface of Cu2O. The CQDs/Cu2O nanocomposite photocatalyst showed a considerable improvement in the CO2 photoreduction with an enhancement of 54% compared to the pure Cu2O. In addition, the band alignment of CQDs/Cu2O, charge carriers transfer and separation as well as possible reaction pathways for CO2 photoreduction was proposed. Finally, the photostability test revealed the CQDs/Cu2O nanocomposite was able to retain its photostability of up to ~90% under five cycles of photoreaction.
关键词： copper (I) oxide,carbon quantum dots,CO2 photoreduction,photocatalyst
更新于2025-09-23 15:21:01
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Photocatalytic degradation of phenol wastewater over Z-scheme g-C3N4/CNT/BiVO4 heterostructure photocatalyst under solar light irradiation
摘要： A series of carbon nanotubes (CNT) modified g-C3N4/BiVO4 photocatalysts were synthesized via wet-impregnation method and evaluated via degradation of phenol under solar light irradiation. The physicochemical properties of the as-developed photocatalyst were characterized using FTIR, XRD, FESEM, XPS, SAP and DR-UV Vis. The formation of g-C3N4/CNT/BiVO4 photocatalysts resulted in remarkable enhancement in the performance in which almost six times higher degradation rate in comparison to the pristine g-C3N4 and obeyed the pseudo-first-order kinetics and Temkin adsorption model. Congruously, the synergistic interaction between 2 wt. % of CNT and 5 vol. % of H2O2 as an oxidizing agent was capable of removing 80.6 % of phenol within 120 minutes. The profound photodegradation performance monitored was attributed to the better crystallinity structure obtained as shown in XRD and XPS analysis. Furthermore, the intimate contact between the CNT, g-C3N4 and BiVO4 in the heterostructure sample as shown in FESEM micrograph images does help in allowing a smooth electron-hole pair separation and migration, resulting in more available ?OH and ?O2ˉ radicals for photocatalytic degradation activities. The possible Z-scheme reaction mechanism has been proposed and active species trapping experiments have been carried out to find the role of active radical species responsible for the phenol degradation. Additionally, the g-C3N4/CNT/BiVO4 photocatalysts retained excellent stability even after several cycles. Congruently, a mathematical representation for understanding the interaction between CNT loading and H2O2 for photodegradation of phenol using response surface methodology (RSM) was successfully generated.
关键词： phenol degradation,bismuth vanadate,carbon nanotube,wastewater,graphitic carbon nitride,photocatalyst
更新于2025-09-23 15:21:01
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Establishing a new hot electrons transfer channel by ion doping in plasmonic metal/semiconductor photocatalyst
摘要： A straightforward strategy is developed to improve the injection efficiency of hot electrons in Ag/TiO2 plasmonic photocatalyst by introducing the Fe dopant. The Fe dopant energy level formed within the bandgap of TiO2 provides an extra electron transfer channel for transferring the hot electrons induced by plasmonic Ag nanoparticles.
关键词： hot electrons,plasmonic photocatalyst,Ag nanoparticles,TiO2,Fe dopant
更新于2025-09-23 15:21:01
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Theoretical design of InSe/GaTe VDW heterobilayer: A potential visible-light photocatalyst for water splitting
摘要： Using first-principles calculations, we show that two-dimensional (2D) van der Waals (vdW) InSe/GaTe heterobilayer (HBL) can serve as a potential visible-light-driven photocatalyst for water splitting to produce hydrogen, which notably improves the photocatalytic performance over isolated InSe and GaTe monolayers. The type-II band alignment and high carrier mobility of the InSe/GaTe HBL facilitate the spatial separation of photo-generated carriers and thus enhances the photocatalytic efficiency. Meanwhile, the separated absorption of H+ and OH- on the surfaces of InSe/GaTe HBL is beneficial to the photocatalytic redox reactions. Moreover, InSe/GaTe HBL can significantly extend the range of light harvesting from visible-light to infrared-light. The predicted maximum power conversion efficiency (PCE) attains 12.3%. These results indicate the InSe/GaTe HBL is a promising photocatalyst for water splitting.
关键词： water splitting,InSe/GaTe heterobilayer,photocatalyst,first-principles calculations,visible-light
更新于2025-09-23 15:21:01
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Z-scheme recyclable photocatalysts based on flower-like nickel zinc ferrite nanoparticles/ZnO nanorods: Enhanced activity under UV and visible irradiation
摘要： Hybrid photocatalysts with magnetism are important because of their advantage of being recyclable by a magnet. In this paper, we report the synthesis of magnetic flower-like nanocomposites based on ZnO nanorods and nickel zinc ferrite (NZF) nanoparticles using a hydrothermal method. The magnetic cores of NZF nanoparticles with diameter of 30e50 nm were used as the centers for the subsequent ZnO nanorods growth. ZnO nanorods grow from these magnetic cores to form scattered flower-like nanostructures, while their length is controlled by changing the heating time. These flower-like nanostructures have distinctive morphology with large surface-to-volume (S/V) ratio. When used as a photocatalyst, these hierarchical nanocomposites show high photocatalytic activity in the degradation of organic contaminates under ultraviolet (UV) and visible light irradiation. Their excellent photocatalysis attributes to the wide absorption range of NZF and the simple Z-scheme system between ZnO and NZF that enhances the charge separation efficiency. In addition, these nanocomposites present sufficient magnetization such that they can be rapidly separated from the solution by a magnet. These recyclable photocatalysts with high efficiency under UV and visible light are ideal for purifying organic contaminants.
关键词： Photocatalyst,Recyclable,Nickel zinc ferrite
更新于2025-09-23 15:21:01
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Effect of Substituents on TiO <sub/>2</sub> Photocatalytic Oxidation of <i>trans</i> -Stilbenes
摘要： Photocatalytic reaction of trans-stilbene on TiO2 particles in acetonitrile-water mixed solvent produces benzaldehyde with high selectivity. Introduction of electron-donating substituents to the benzene rings accelerated the reaction. On the other hand, the rate was decelerated by electron-withdrawing substituents. These results suggest that the reaction proceeds by hydroperoxo or hydroperoxy, which were formed on TiO2 surface by UV irradiation, rather than free OH radicals.
关键词： Epoxidation,Photocatalyst,TiO2
更新于2025-09-23 15:21:01
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Visible Light Photocatalytic Activity of NaYF4:(Yb,Er)-CuO/TiO2 Composite
摘要： TiO2 photocatalysts are limited to ultraviolet light photo-activation, however, by coupling with NaYF4:(Yb,Er) they can utilize visible light activation, but with low efficiencies. In order to enhance visible light photo-activity, CuO nanoparticles were coupled with NaYF4:(Yb,Er) by mechanical ball-milling and coated with TiO2-sol. The coupling of CuO nanoparticles with NaYF4:(Yb,Er)/TiO2 caused the formation of a NaYF4:(Yb,Er)-CuO/TiO2 composite capable of visible absorption with a remarkably reduced band gap of ~2.5 eV. The NaYF4:(Yb,Er)-CuO/TiO2 composite in H2O2 showed the most efficient methylene blue (MB) degradation efficiency of more than 99.5% after exposure to visible light.
关键词： visible light,NaYF4:(Yb,Er)-CuO/TiO2,composites,photocatalyst
更新于2025-09-23 15:21:01
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Semiconductor Photocatalysis - Materials, Mechanisms and Applications || Photocatalytic Removal of Organics over BiVO4-Based Photocatalysts
摘要： Organic compounds, such as organic dyes and phenols, are the main pollutants in wastewater. In the past years, a large number of studies on the fabrication and photocatalytic organics degradation of BiVO4 and its related materials have been reported in the literature. In this chapter, we shall focus on the advancements in the synthesis and photocatalytic applications of several kinds of BiVO4-based photocatalysts: (i) well-defined morphological BiVO4 photocatalysts, (ii) porous BiVO4 photocatalysts, (iii) heteroatom-doped BiVO4 photocatalysts, (iv) BiVO4-based heterojunction photocatalysts, and (v) supported BiVO4 photocatalysts. We shall discuss the structure–photocatalytic performance relationship of the materials and the involved photocatalytic degradation mechanisms. In addition, we also propose the research trends and technologies for practical applications of the BiVO4-based photocatalytic materials.
关键词： BiVO4-based heterojunction,well-defined morphology,heteroatom-doped BiVO4,supported BiVO4,porous BiVO4 photocatalyst
更新于2025-09-23 15:21:01
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Semiconductor Photocatalysis - Materials, Mechanisms and Applications || Alternative Approaches in Development of Heterogeneous Titania-Based Photocatalyst
摘要： Three alternative approaches for the development of heterogeneous photocatalysts are comparatively evaluated, namely (i) the use of molecular imprinting concept for the development of heterogeneous catalysts employing rhodamine B as template and sol–gel as synthesis route; (ii) the impregnation of TiCl4 on mixed nano- and micro-metric silicas, followed by calcination; (iii) the use of industrial and academic chemical residues as source of potential photocatalyst species impregnated on supports. All tests were carried on with rhodamine B as target molecule. For comparative reasons, photocatalytic tests were carried out with commercial titania (P25). The solids were characterized by nitrogen porosimetry, small-angle X-ray scattering (SAXS), zeta potential (ZP), diffuse reflectance spectroscopy in the ultraviolet region (DRS-UV), diffuse reflectance infrared Fourier transmission spectroscopy (DRIFTS), and Rutherford backscattering spectrometry (RBS). The supported catalysts resulting from silica nanoparticles and residue of the petrochemical industry achieved higher percentage of the dye degradation under ultraviolet (68.0 and 66.8%, respectively) radiation. The industrial waste reached the highest photocatalytic activity under visible (61%) radiation, while the commercial P25 achieved 82.0and 12.3% for ultraviolet and visible radiation, respectively. The textural and structural characteristics of the supported catalyst prepared with fumed silica and petrochemical waste (SiPe), namely the low-energy bandgap (1.8 eV), large surface area (280 m2 g?1), high pore volume (1.9 cm3 g?1), and high zeta potential value (?36.4 mV), may have been responsible for their high activity.
关键词： supported photocatalyst,molecular imprinting,Rhodamine B,titania,residue,silicas
更新于2025-09-23 15:21:01