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- 实验方案
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Enhanced Photocatalytic Activity of B, N-Codoped TiO <sub/>2</sub> by a New Molten Nitrate Process
摘要： B, N-codoped titania mesoporous crystals were prepared by the sol–gel method followed by a molten nitrate process to modify the sample morphology. The composition, morphology and microstructure of the obtained samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), Brunauer Emmett Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). Fourier Transform Infrared spectroscopy (FTIR) revealed weak complex vibrations between the Ti–O oxide species and the unsaturated sites (Ti3+) through the incorporation of hydroxyl groups, which was not observed in the bulk titania (B–N–TiO2). The photocatalytic reactivity of boron-nitrogen codoped TiO2 was examined for the removal of methylene blue (MB) under visible light irradiation. The nitrates treated B-doped TiO2 exhibited better photocatalytic activity for dye degradation than that of B-doped TiO2 and nitrates treated TiO2. The best performance was obtained in the sample treated at a calcination temperature of 550 °C.
关键词： Photocatalysis,Visible Light,Nitrate,Boron Doped Titanium Dioxide
更新于2025-09-09 09:28:46
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A Review on BiOX (X= Cl, Br and I) Nano-/Microstructures for Their Photocatalytic Applications
摘要： In the recent past, bismuth oxyhalides (BiOX) have been widely used for the photocatalytic degradation of the organic pollutants and other environmental remediation because of their higher stability, economic viability, nontoxicity and effective charge separation. We begin with the review of the different approaches adopted so far for BiOX (X = Cl, Br, and I) synthesis and a study of their photocatalytic performances under UV and visible light towards the various organic as well as inorganic pollutants. Later on, a study on further enhancement of the ef?ciency of BiOX under UV and visible light irradiation using recent advancements would be presented. The new approaches involve controlled morphology by forming composite and hybrid materials with other semiconductors and also doping with other metals and nonmetals that would undoubtedly be bene?cial in the interfacial charge transfer and ef?cient inhibition of the photo-generated species. Herein, we would also exploit the recent developments in the research strategies for enhancing photocatalytic activity of BiOX.
关键词： Pollutants,Photocatalysts,Functionalization,Stability,Bismuth Oxyhalides,Heterostructures,Photogenerated Species,Environmental Remediation,Composites,Photodegradation,Visible Light
更新于2025-09-09 09:28:46
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Shape Tailored TiO <sub/>2</sub> Nanostructures and Their Hybrids for Advanced Energy and Environmental Applications: A Review
摘要： Shape tailored TiO2 nanostructures with various dimensionality (zero to three dimension) have unique physicochemical and functional properties that facilitates its efficient energy and environment applications, e.g., solar light driven photocatalytic hydrogen generation and decontamination of organic/inorganic toxic pollutants, CO2 reduction into the hydrocarbon fuels, solar cells, supercapacitors and lithium-ion batteries etc. However, the wide band gap nature and the fast recombination of the photogenerated charge carriers in TiO2 usually limit its overall performance under solar light illumination. In this review, we present a state of the art on the fabrication techniques of shape tailored TiO2 nanostructures and the strategies employed to make the system catalytically more efficient. Though shape tailored TiO2 nanostructures with large specific surface area and highly energetic (001) facet exposed TiO2 nanostructures (2D and 3D) can enhance the photocatalytic efficiency to a reasonable extent, further surface engineering is needed for the modification of the electronic band arrangement, visible light sensitization and efficient charge separation. Herein, TiO2 heterostructures (HSs) with metal/non-metal doping, surface fluorination, plasmonic noble metal nanoparticles (NPs) and coupling with the narrow band gap suitable semiconductor (type-II) are discussed in details covering from zero dimensional to three dimensional heterostructures. The synthesis strategies, charge transfer mechanism and their participation in the photocatalysis are elaborated. Though one dimensional TiO2 HSs have been widely studied, we present the recent development of critical surface engineering strategies of two and three dimensional systems, which give rise to the excellent properties including the enlargement of surface area, light absorption capability and efficient separation of electrons/holes resulting in the superior performance in advanced applications. Based on recent breakthroughs in the field, future directions and outlook of the field are presented at the end.
关键词： Type-II Heterostructure,2D TiO2,3D TiO2,Shape Tailored TiO2 Nanostructures,1D TiO2,Visible Light Photocatalysis,Hydrogen Production,0D TiO2,Plasmonic Heterostructure
更新于2025-09-09 09:28:46
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Optical Filter Designs for Multi-Color Visible Light Communication
摘要： In visible light communication (VLC), using multiple colors is an efficient way to enhance data rate, leading to multi-color VLC (MC-VLC). However, the performance of MC-VLC is jeopardized by the spectral overlaps of different colors. Thin-film optical filters, as the key component of MC-VLC systems, are usually adopted to separate colors. The passband bandwidth (BW) and center wavelength (CWL) of optical filters are critical to mitigate the crosstalk among colors, and thus must be carefully designed. Moreover, due to the intrinsic wavelength shift of the CWL with the varying of the angle of incidence (AoI), it is challenging to support mobility for MC-VLC. In this paper, we consider a joint design of multiple optical filters for MC-VLC by properly selecting the BW and CWL of each filter. We first investigate the optical filter design for a fixed receiver location. Then, to support mobility, we propose two robust optical filter designs, namely statistically and worst-case robust designs, which do not rely on the exact receiver location. Efficient methods are developed to solve the corresponding design problems and obtain the optimized optical filters. Compared with the existing optical filters, the proposed optical filters exhibits much better performance in various scenarios.
关键词： robust design,optical filter,spectrum shift,Mobility,multi-color LED,visible light communication,spectral overlap
更新于2025-09-09 09:28:46
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Visible-light-responsive Photocatalyst of Graphitic Carbon Nitride for Pathogenic Biofilm Control
摘要： Pathogenic biofilms raise significant health and economic concerns, because these bacteria are persistent and can lead to long-term infections in vivo and surface contamination in healthcare and industrial facilities or devices. Compared with conventional antimicrobial strategies, photocatalysis holds promise for biofilm control because of its broad-spectrum effectiveness under ambient conditions, low cost, easy operation, and reduced maintenance. In this study, we investigated the performance and mechanism of Staphylococcus epidermidis biofilm control and eradication on the surface of an innovative photocatalyst, graphitic carbon nitride (g-C3N4), under visible light irradiation, which overcame the need for ultraviolet (UV) light for many current photocatalysts (e.g., titanium dioxide (TiO2)). Optical coherence tomography (OCT) and confocal laser scanning microscopy (CLSM) suggested that g-C3N4 coupons inhibited biofilm development and eradicated mature biofilms under the irradiation of white light-emitting diodes (LEDs). Biofilm inactivation was observed occurring from the surface towards the center of the biofilms, suggesting that the diffusion of reactive species into the biofilms played a key role. By taking advantage of scanning electron microscopy (SEM), CLSM, and atomic force microscopy (AFM) for biofilm morphology, composition, and mechanical property characterization, we demonstrated that photocatalysis destroyed the integrated and cohesive structure of biofilms and facilitated biofilm eradication by removing the extracellular polymeric substances (EPS). Moreover, reactive oxygen species (ROS) generated during g-C3N4 photocatalysis were quantified via reactions with radical probes, and 1O2 was believed to be responsible for biofilm control and removal. Our work highlights the promise of using g-C3N4 for a broad range of antimicrobial applications, especially for the eradication of persistent biofilms under visible light irradiation, including photodynamic therapy, environmental remediation, food industry applications, and self-cleaning surface development.
关键词： graphitic carbon nitride,mechanical properties,extracellular polymeric substances,biofilms,visible light
更新于2025-09-09 09:28:46
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Fabrication and Performances of Graphene/TiO2 Composites Derived from Graphenes and Titanium(IV) Alkoxide Precursors
摘要： Graphene/TiO2 composites were synthesized by sol-gel technique using titanium(IV) n-butoxide (TNB), titanium(IV) isopropoxide (TIP) and titanium(IV) propoxide (TPP) as different titanium alkoxide precursors. The as-prepared composites were characterized by BET surface area, SEM, XRD, EDX and UV-visible absorption spectroscopy. The samples were evaluated for their photocatalytic activity towards the degradation of methylene blue (MB) under UV irradiation. The results indicated that the sample GTNB had best excellent photocatalytic activity among the three kinds of samples. According to the photocatalytic results, methylene blue removal by a treatment with graphene/TiO2 composites seems to have an excellent removal effect as order of GTIP, GTNB and GTPP composites due to a photolysis of the supported TiO2, the radical reaction and the adsorptivity and absorptivity of the graphene.
关键词： TiO2,Visible light,Graphene,Photocatalytic,TEM
更新于2025-09-09 09:28:46
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Visible-Light-Driven Conversion of CO2 to CH4 with an Organic Sensitizer and an Iron Porphyrin Catalyst
摘要： Using a phenoxazine-based organic photosensitizer and an iron porphyrin molecular catalyst, we demonstrated photochemical reduction of CO2 to CO and CH4 with turnover numbers (TONs) of 149 and 29, respectively, under visible light irradiation (λ > 435 nm) with a tertiary amine as sacrificial electron donor. This work is the first example of a molecular system using an earth-abundant metal catalyst and an organic dye to effect complete 8e-/8H+ reduction of CO2 to CH4, as opposed to typical 2e-/2H+ products of CO or formic acid. The catalytic system continuously produced methane even after prolonged irradiation up to four days. Using CO as the feedstock, the same reactive system was able to produce CH4 with 85% selectivity, 80 TON and a quantum yield of 0.47%. The redox properties of the organic photosensitizer and acidity of the proton source were shown to play a key role in driving the 8e-/8H+ processes.
关键词： methane,organic photosensitizer,CO2 reduction,iron porphyrin,visible light
更新于2025-09-09 09:28:46
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Synthesis of Self-Gravity Settling Faceted-Anatase TiO2 with Dominant {010} Facets for the Photocatalytic Degradation of Acetaminophen and Study of the Type of Generated Oxygen Vacancy in Faceted-TiO2
摘要： In this study, faceted TiO2, predominately exposed with {010} facets (T-{010}), was synthesized with a two-step hydrothermal reaction and used for the degradation of acetaminophen (ACE) in an aqueous solution. T-{010} showed considerable photocatalytic reactivity, and its easy-settling (gravity-settling, ~97% of T-{010} settled after 30 min) property demonstrated acceptable reusability. A solid-state chemical reduction approach (NaBH4) at a mild temperature (300 ?C) was used for generation of an oxygen vacancy in T-{010} and P25 (commercial TiO2). The oxygen vacancy concentrations of the samples were investigated by electron paramagnetic resonance (EPR). It was also found that NaBH4 reduction induced the generation of both surface and subsurface Ti3+ on colored P25, but only surface Ti3+ species were formed on colored T-{010}. The prepared colored TiO2 samples were successfully used for photocatalytic degradation of ACE in an aqueous solution under visible light illumination.
关键词： photocatalytic degradation,visible light,{010} facet,oxygen vacancy,settling
更新于2025-09-09 09:28:46
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Photocatalytic performance of Ag2S/ZnO/ZnS nanocomposites with high visible light response prepared via microwave-assisted hydrothermal two-step method
摘要： A series of different ratios of Ag2S/ZnO/ZnS nanocomposites with visible light response were prepared by a microwave-assisted hydrothermal two-step method, whose composition, crystalline structure, morphology and surface physicochemical properties were well-characterized via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis/DRS), photoluminescence spectrum (PL), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and N2 adsorption–desorption measurements. Results showed that as-composites mainly consisted of ZnS crystal phase, whose grain size increased obviously compared with non Ag2S samples. At the same time, due to the introduction of narrow band gap Ag2S, the synthesized composite can effectively increase the visible optical absorption of ZnO/ZnS composites. Among them, 1% Ag2S/ZnO/ZnS showed a mixed structure of nano-line and nano-particle, of which BET value increased significantly, and the morphology was more excellent. Photocatalytic activities of a series of Ag2S/ZnO/ZnS composites under different light sources were studied using methyl orange as a model molecule, and 1% Ag2S/ZnO/ZnS was taken as the best one. Meanwhile, 1% Ag2S/ZnO/ZnS also showed a good degradation effect on other dyes with different structures, and its degradation efficiency did not change significantly after three cycles, showing certain stability. In addition, composites with Ag2S loading of 1% possessed the highest hydrogen production ability of photolysis water, indicating that the introduction of Ag2S had significantly enhanced the catalytic performance.
关键词： microwave-assisted,Ag2S,photocatalysis,visible light,photolysis of water to hydrogen,ZnO/ZnS
更新于2025-09-09 09:28:46
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Construction of Ternary rGO/Ag <sub/>2</sub> CO <sub/>3</sub> /AgBr Heterostructured Photocatalyst for Improved Photocatalytic Activity and Stability
摘要： Novel ternary rGO/Ag2CO3/AgBr heterostructured photocatalyst have been successfully fabricated through in-situ anion exchange synthesis route. The morphology, crystal structure, component and optical property of the as-obtained products were fully characterized by various technologies. The photocatalytic performances of the as-obtained products were measured by degrading rhodamine B (RhB) under visible light irradiation. The rGO/Ag2CO3/AgBr heterostructured photocatalyst exhibits higher photocatalytic activity than that of the pure Ag2CO3 and rGO/Ag2CO3, indicating the presence of a synergic effect between three components. The superior photocatalytical activity for the rGO/Ag2CO3/AgBr heterostructured photocatalyst is due to the formation of multi-heterojunction with rGO acting as electron mediation, which facilitate the separation of photogenerated electron and hole pairs. The possible transfer path of photogenerated carriers and mechanism for the improved photocatalytic activity are also supposed.
关键词： AgBr,Ternary Heterojunction,Ag2CO3,Photocatalysis,Visible Light Driven
更新于2025-09-09 09:28:46