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Construction of Z-Scheme g-C3N4/CNT/Bi2Fe4O9 Composites with Improved Simulated-Sunlight Photocatalytic Activity for the Dye Degradation
摘要： In this work, ternary all-solid-state Z-scheme g-C3N4/carbon nanotubes/Bi2Fe4O9 (g-C3N4/CNT/BFO) composites with enhanced photocatalytic activity were prepared by a hydrothermal method. The morphology observation shows that ternary heterojunctions are formed in the g-C3N4/CNT/BFO composites. The photocatalytic activity of the samples for the degradation of acid orange 7 was investigated under simulated sunlight irradiation. It was found that the ternary composites exhibit remarkable enhanced photocatalytic activity when compared with bare BFO and g-C3N4/BFO composites. The effect of the CNT content on the photocatalytic performance of the ternary composites was investigated. The photocatalytic mechanism of g-C3N4/CNT/BFO was proposed according to the photoelectrochemical measurement, photoluminescence, active species trapping experiment and energy-band potential analysis. The results reveal that the introduction of CNT as an excellent solid electron mediator into the ternary composites can effectively accelerate the electron migration between BFO and g-C3N4. This charge transfer process results in highly-ef?cient separation of photogenerated charges, thus leading to greatly enhanced photocatalytic activity of g-C3N4/CNT/BFO composites. Furthermore, the g-C3N4/CNT/BFO composites also exhibit highly-ef?cient photo-Fenton-like catalysis property.
关键词： CNT,Bi2Fe4O9,photocatalysis,Z-scheme heterojunction,g-C3N4
更新于2025-09-10 09:29:36
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Synthesis, Characterization of g-C3N4/SrTiO3 Heterojunctions and Photocatalytic Activity for Organic Pollutants Degradation
摘要： Perovskite-structure SrTiO3 (STO) and graphitic carbon nitride (g-C3N4, CN) have attracted considerable attention in photocatalytic technology due to their unique properties, but also suffer from some drawbacks. The development of composite photocatalysts that combine properties of the individual semiconductors with enhanced charge separation is the current major trend in the photocatalysis field. In this study, SrTiO3/g-C3N4 (CNSTO) composites with different ratios (10, 20, 30, 40 and 50% g-C3N4) were prepared with a sonication mixing method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 porosimetry, Fourrier transform infra-red spectroscopy (FT-IR), UV-Vis diffuse reflectance (DRS) and dynamic light scattering (DLS). STO spherical particles were successfully loaded on the g-C3N4 planes forming heterojunction composite materials. The photocatalytic activity was tested against the degradation of methylene blue (MB) dye under simulated solar light (SSL) irradiation following first-order kinetics. The photocatalytic activity followed the trend: 20CNSTO > 30CNSTO > 40CNSTO > 50CNSTO ≈ 10CNSTO, in accordance with the amount of ?OH radicals determined by fluorescence spectroscopy. A Z-scheme mechanism was proposed for the enhanced photocatalytic degradation of MB as evidenced by trapping experiments with scavengers. Finally, significant stability and reusability was exhibited, indicating that such composites are of potential interest for photocatalytic treatments under sunlight irradiation.
关键词： composites,heterojunction,Z-scheme,g-C3N4/SrTiO3,photocatalysis
更新于2025-09-10 09:29:36
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Recent development of g-C3N4-based hydrogels as photocatalysts: A minireview
摘要： Solar-driven photocatalysis using graphitic carbon nitride (g-C3N4) is considered the most promising approach for the generation of H2 from water, degradation of organic pollutants, and reduction of CO2. However, bulk g-C3N4 exhibits several drawbacks, such as low specific surface area, high defect density, and fast charge recombination, which result in low photocatalytic performance. Construction of 3D porous hydrogels for g-C3N4 through nanostructural engineering is a rapid, feasible, and cost-effective technique to improve the adsorption capability, stability, and separability of the hydrogel composite; to increase the number of active sites; and to create an internal conductive path for facile charge transfer and high photocatalytic activity. This minireview summarizes the recent progresses in photocatalytic water splitting and dye degradation using g-C3N4-based hydrogels with respect to the state-of-the-art methods of synthesis, preparation, modification, and multicomponent coupling. Furthermore, comprehensive outlooks, future challenges, and concluding remarks regarding using g-C3N4-based hydrogels as highly efficient photocatalysts are presented.
关键词： water splitting,hydrogels,photocatalysts,dye degradation,g-C3N4
更新于2025-09-10 09:29:36
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Facile Synthesis of Carbon/g-C <sub/>3</sub> N <sub/>4</sub> ?Nanocomposites as Metal-Free Photocatalyst?with Enhanced Visible-Light-Responsive Photocatalytic Properties
摘要： The development of highly effective metal-free photocatalysts in place of traditional photocatalysts is of great significance for environmental remediation by utilization of solar energy. In this work, a new 2D carbon/g-C3N4 metal-free photocatalyst was designed and fabricated via one-step thermal treatment of cyanamide and spent tea leaves (STL). The as-prepared samples were fully characterized and the results revealed that carbon nanosheets are evenly attached on the surface of g-C3N4 by chemical bonds rather than simple physical stacking, which is beneficial to the strong interface interaction. The intimate interfacial bonding of carbon materials with g-C3N4 exhibit enlarged specific surface area, broadened photo-response range, efficient photo-induced electron migration as well as high stability. Thus, the carbon/g-C3N4 photocatalyst showed remarkable enhanced photocatalytic activities in the degradation of antibiotic ciprofloxacin (CIP) in aqueous solution and gaseous benzene than that of pristine g-C3N4 under visible light. Furthermore, a possible photocatalytic mechanism for the improved photocatalytic performance over carbon/g-C3N4 nanocomposites was proposed. This research work can promote the exploration on facile synthesis of total metal-free carbon/g-C3N4 photocatalysts with biomass as the carbon source and its application in environmental pollutants elimination.
关键词： g-C3N4,Environmental remediation,Photocatalysis,Carbon
更新于2025-09-10 09:29:36
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Enhanced Electron Separation on in-Plane Benzene-Ring Doped g-C3N4 Nanosheets for Visible Light Photocatalytic Hydrogen Evolution
摘要： Solar-to-chemical energy conversion by photocatalytic hydrogen evolution (PHE) is critical for reduction of the pollution and storage of clean energy. To improve the solar conversion efficiency, it is highly imperative to accelerate the photocarrier separation and transportation through materials design. Herein, we describe a highly effective PHE catalyst based on in-plane benzene-ring doped g-C3N4 nanosheets heterostructure through the thermal co-polymerization of urea and 4, 4'-sulfonyldiphenol (BPS) followed by a controlled heat-etching step. The solid-state 13C NMR confirms the existence of benzene-ring structure in g-C3N4 nanosheets. Experimental results and theoretical calculations show that the energy and electronic structure of the catalyst are optimally regulated, inducing increased light absorption and effectively accelerated separation of the photo-driven charge carriers. It exhibits enhanced photocatalytic hydrogen evolution efficiency with a PHE rate of 12.3 mmol h-1 g-1 (almost 12 times higher than that of pure g-C3N4 nanosheets) and the quantum efficiency of 17.7 % at 420 nm.
关键词： g-C3N4,hydrogen evolution,in-plane,benzene-ring doping,photocatalysis
更新于2025-09-10 09:29:36
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Enhanced visible light photoreduction of aqueous Cr(VI) by Ag/Bi4O7/g-C3N4 nanosheets ternary metal/non-metal Z-scheme heterojunction
摘要： In this paper, we successfully constructed a ternary metal/non-metal nanomaterial which can synergize Z-scheme heterojunction and plasmonic metal/semiconductor for enhancing visible light photoreduction of aqueous Cr(VI). The as-formed ternary metal/non-metal nanomaterial was composed of g-C3N4 nanosheets mutual modified by Ag nanoparticles and Bi4O7. In the ternary nanomaterial, g-C3N4 nanosheets and Bi4O7 fabricated Z-scheme heterojunction, g-C3N4 nanosheets and Ag nanoparticles formed plasmonic metal/semiconductor system, synchronously. The photodeposition experiments were designed to indirect demonstrate the Z-scheme heterojunction via photocatalytic oxidation and reduction deposition reactions, AgNO3 was used as the electron acceptor and Pb(NO3)2 as the electron donor, photocatalytic reduction product and oxidation product were selectively deposited on g-C3N4 nanosheets and Bi4O7, respectively, revealing the Z-scheme heterojunction was definite formed. In addition, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), UV–vis absorption, and Fourier-transform infrared spectroscopy (FTIR) were studied to indicate that the plasmonic metal/semiconductor system was existent in the ternary nanomaterial. The visible light photoreduction of ternary Ag/Bi4O7/g-C3N4 nanosheets was evaluated by photoreducing aqueous Cr(VI). The photoreduction results show that the ternary Ag/Bi4O7/g-C3N4 nanosheets is much higher than the pristine bulk g-C3N4 and g-C3N4 nanosheets.
关键词： Visible light,Z-scheme heterojunction,g-C3N4,Bi4O7,Cr(VI) reduction,Ag nanoparticles
更新于2025-09-10 09:29:36
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Well-dispersed zero-valent iron supported on Fe3O4/g-C3N4 composites via a facile approach with versatile photoredox catalysis
摘要： A well-dispersed Fe0/Fe3O4/g-C3N4 ternary hybrid composition was successfully synthesized through a calcination route followed by a hydrothermal treatment. It was significant to find that Fe0/Fe3O4/g-C3N4 possesses the optimal photocatalytic efficiency and excellent reusability toward Cr(VI) and RhB. The enhanced photocatalytic efficiency was attributable to the comprehensive factors including intimate contact of Fe0/Fe3O4 with g-C3N4, efficacious recombination inhibition of photoexcited carries, and synergistic interaction between each composition. Moreover, the photoredox catalytic mechanism of Fe0/Fe3O4/g-C3N4 was clearly proved by transient photocurrent responses, PL spectra properties, and exploring the formed active radicals that contribute to the improved photoredox activity. It is expected that our work could offer a notional guidance to design a promising photocatalytic compound for simultaneously degrading heavy metal ions and organic pollutant.
关键词： High-dispersed,Photostability,Synergistic,Fe0/Fe3O4/g-C3N4,Photocatalytic,Nanostructured catalysts
更新于2025-09-10 09:29:36
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Enhanced photocatalytic Cr(VI) reduction and diclofenac sodium degradation under simulated sunlight irradiation over MIL-100(Fe)/g-C3N4 heterojunctions
摘要： Metal-organic framework MIL-100(Fe) and g-C3N4 heterojunctions (MG-x, x = 5%, 10%, 20%, and 30%, x is the mass fraction of MIL-100(Fe) in the hybrids) were facilely fabricated through ball-milling and annealing, and characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, UV-visible diffuse-reflectance spectrometry, and photoluminescence emission spectrometry. The photocatalytic activities of the series of MG-x heterojunctions toward Cr(VI) reduction and diclofenac sodium degradation were tested upon irradiation with simulated sunlight. The influence of different organic compounds (ethanol, citric acid, oxalic acid, and diclofenac sodium) as hole scavengers and the pH values (2, 3, 4, 6, and 8) on the photocatalytic activities of the series of MG-x heterojunctions was investigated. MG-20% showed superior photocatalytic Cr(VI) reduction and diclofenac sodium degradation performance than did the individual MIL-100(Fe) and g-C3N4 because of the improved separation of photoinduced electron-hole charges, which was clarified via photoluminescence emission and electrochemical data. Moreover, the MG-x exhibited good reusability and stability after several runs.
关键词： MIL-100(Fe),Cr(VI) reduction,g-C3N4,Heterojunction,Diclofenac sodium
更新于2025-09-10 09:29:36
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Construction of TiO2-Fe-C3N4 compound: Promotion of interfacial charge transfer effect through facile energy level alignment
摘要： An efficient visible-light-driven photocatalyst with interfacial electron transfer (IFCT) effect was prepared by introducing a facile energy level alignment in heterostructured TiO2-Fe-C3N4, where IFCT was promoted strongly due to the effective electron transfer. The Fe (III) clusters grafted on the TiO2 microspheres, extended the photo response of TiO2 from UV to visible light region, resulting in better light absorption capability. What’s more, the direct transfer of photoinduced electrons from TiO2/Fe to C3N4 was observed, which promoted the IFCT effect, leaving the high oxidizing holes in the valence band (VB) of TiO2 and conduction band (CB) of C3N4 for further degradation. The TiO2-Fe-C3N4 exhibited much better photocatalytic performance for methyl orange degradation and higher photocurrent under visible light irradiation than the bare TiO2 or C3N4, which was attributed to the synergistic effect between TiO2 and Fe/C3N4 as well as C3N4 and TiO2/Fe. In addition, the photo-induced holes in the VB of the TiO2 microspheres was confirmed by ESR analysis and a possible photocatalytic mechanism of TiO2-Fe-C3N4 composite under visible light irradiation was also proposed.
关键词： IFCT,C3N4,photocatalysis,TiO2
更新于2025-09-10 09:29:36
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Insight into photocatalytic activity, universality and mechanism of copper/chlorine surface dual-doped graphitic carbon nitride for degrading various organic pollutants in water
摘要： It is still a challenging work to realize the universality of photocatalytic materials for unselective removing various organic pollutants in water. Here a surface dual-doped Cu/Cl-g-C3N4 photocatalyst is firstly prepared, which exhibits much more superior photocatalytic performance for degrading multifarious persistent organic pollutants including tetracycline hydrochloride (TC-HCl), o-chlorophenol, bisphenol A and 2-mercaptobenzothiazole in water than pure g-C3N4. The high-efficiency and unselective photocatalytic degradation performance derives from the surface dual-doped effect of Cu/Cl elements on g-C3N4, which results in the extended visible light harvest range, elevated CB potential and improved the separation efficiency of charge carriers. The intermediate products, degradation pathway, degree of mineralization and reaction mechanism of representative TC-HCl pollutant over the surface dual-doped Cu/Cl-g-C3N4 photocatalyst are revealed in depth. This work makes an important development for treating the persistent organic pollutants in the water environments by exploiting new, low-cost and high-efficiency photocatalytic materials.
关键词： reaction mechanism,photocatalytic degradation,dual-doped Cu/Cl-g-C3N4,various organic pollutants,universality
更新于2025-09-10 09:29:36