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Photocatalytic solar fuel production and environmental remediation through experimental and DFT based research on CdSe-QDs-coupled P-doped-g-C3N4 composites
摘要： Solar energy harvesting and conversion into useful chemical energy with the aid of semiconductor photocatalysts is a promising technique to solve both energy and environmental issues. This work reports a successful synthesis of CdSe quantum dots (QDs) modified phosphorus doped g-C3N4 (P-CN) for advanced photocatalytic applications. Phosphorus doping and structural coupling with CdSe QDs are shown to significantly extend visible-light response of g-C3N4 up to 700 nm. The optimized sample 4CdSe/P-CN demonstrates enhanced visible-light driven overall water splitting activities for H2 and O2 evolution i.e. 113 and 55.5 μmol.h?1.g?1, respectively, as well as very high photocatalytic CO2 to CH4 conversion efficiency (47 μmol.h?1.g?1). It also exhibit higher activity (78 %) for 2,4-dichlorophenol degradation as compared to pristine CN-sample. Combined photoluminescence, transient/single wavelength photocurrent, photoelectrochemical, and coumarin fluorescence spectroscopy demonstrate that 4CdSe/P-CN nanocomposite exhibit enhanced charge separation efficiency which is responsible for improved visible light catalytic activities. Our work thus provide a new strategy to design low-cost and sustainable photocatalysis with wide visible-light activity for practical overall water splitting and CO2 reduction applications.
关键词： Expending visible-light response,g-C3N4,Phosphorus doping,Solar fuel,CdSe quantum dots
更新于2025-09-23 15:21:01
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Explosive thermal exfoliation of intercalated graphitic carbon nitride for enhanced photocatalytic degradation properties
摘要： Dicyandiamide derived graphitic carbon nitride (g-C3N4) was chemically intercalated by concentrated H2SO4 firstly, followed by a rapid heating treatment. Molecules between the stacking layers of g-C3N4 produced an explosive effect upon rapid heating to thermally exfoliate g-C3N4 into porous structures. The appearance color of g-C3N4 changed from light yellow to grey after heating treatment indicating the enhanced light absorption properties, which were identified by the UV-vis absorption test. In addition, photoluminescence intensities of porous g-C3N4 were obviously suppressed compared to those of bulk g-C3N4 samples, indicating the prevention of the recombination process of photogenerated electron-hole pairs. As a result of these simultaneous modifications in texture, optical and electronic properties, the photodegradation kinetics of crystal violet on the catalyst surface can be improved by 4.75 times.
关键词： heating treatment,g-C3N4,photocatalytic degradation,exfoliation
更新于2025-09-23 15:21:01
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Visible light photocatalytic degradation of tetracycline with porous Ag/graphite carbon nitride plasmonic composite: Degradation pathways and mechanism
摘要： Ag/g-C3N4 plasmonic photocatalysts with porous structure ( Ag/PCN ) were successfully synthesized via a thermal exfoliation strategy and photo-reduction method. Owing to the combined merits of porous structure and surface plasmon resonance effect of silver nanoparticles, the Ag/PCN catalysts exhibited excellent photocatalytic performance for the degradation of antibiotic agents. With the optimal Ag loading, the Ag/PCN-2 catalyst exhibited the optimal catalytic activity for TC degradation under visible light, which shows about 11.8 times enhancement in the photocatalytic removal efficiency as compared to pure g-C3N4, respectively. This phenomenon can be attributed to the increased specific surface area, broadened visible light absorption and improved charge separation. The radical quenching results confirmed that h+ and ·O2- radicals were the major active species during removal of TC. The degradation of TC is increased with the increment of Ag/PCN-2 catalysts, and the optimum catalyst was found to be 1.67 g/L. The hindering effect of selected of anions ( Cl-, CO3-, H2PO4- ) was found to follow the order H2PO4- > CO3- > Cl-. Ag/PCN-2 sample also possessed high stability after six cycles of reuses. Furthermore, the possible degradation pathways of TC and photocatalytic mechanism over Ag/PCN-2 were proposed in detail.
关键词： g-C3N4,Antibiotic,Degradation pathway,Photocatalysis,Porous structure,Ag
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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Water hyacinth derived carbon quantum dots and g-C3N4 composites for sunlight driven photodegradation of 2,4-dichlorophenol
摘要： Carbon dots (CDs) were successfully derived from water hyacinth leaves and the binary composite was achieved by incorporating CDs with g-C3N4 through hydrothermal treatment. The average particle size of CDs was found to be 3.1 nm and a blue-green fluorescence was emitted under the UV light irradiation. Both of the composites loaded with 20 wt.% (20CDs/g-C3N4) and 40 wt.% (40CDs/g-C3N4) of CDs achieved the highest degradation efficiency of 2,4-dichlorophenol (2,4-DCP) with 1.7 times higher than that of pure g-C3N4. This work successfully improved the properties of g-C3N4 by elongating the lifetime of photogenerated electrons and widening the visible light response. Both of 20CDs/g-C3N4 and 40CDs/g-C3N4 recorded the highest photocatalytic performance in degrading 2,4-DCP with degradation rate constant of 0.0194, and 0.0186 min?1, respectively. This is contributed by the prolonged charge carrier lifetime in 20CDs/g-C3N4; good visible light absorption and high specific surface area in 40CDs/g-C3N4. For the scavenger test, hole (h+) and superoxide radical (·O2?) were acknowledged as the key active species in photocatalysis.
关键词： Carbon quantum dots,Water hyacinth,CDs/g-C3N4 composite,2,4-Dichlorophenol
更新于2025-09-23 15:21:01
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Fe3+-selective and sensitive “on-off” fluorescence probe based on the graphitic carbon nitride nanosheets
摘要： An effective and facile “on-off” fluorescence sensing approach for the determination of Fe3+ ion using a large area and relatively uniform size graphitic carbon nitride nanosheets (GCNS) was developed. The prepared GCNS have blue and stable emission, as well as excellent water dispersion, and were applied as an effective fluorescent probe that based on the quenched fluorescence for selective and sensitive detection of Fe3+ ion. Herein, we explain the ambiguous fluorescence quenching mechanism between the GCNS and Fe3+, which mainly springs from the redox potential and empty d orbital of Fe3+. The redox potential and unfilled d orbit of Fe3+ endow it excellent binding force with GCNS, which generates most obvious fluorescence quenching effect with respect to other metal ions. The limit of detection (LOD) for Fe3+ was found to be about 2.06 μM. Therefore, the prepared GCNS has the potential to be used as a fluorescent probe for detection.
关键词： nanosheets,fluorescence detection,g-C3N4,fluorescence quenching mechanism
更新于2025-09-23 15:21:01
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BiOCl Nanoplates Decorated on g-C3N4 for Enhanced Photocatalytic Activities
摘要： A facile solvothermal method has been successfully developed for the preparation of BiOCl/g-C3N4 nanocomposite using sodium dodecyl benzene sulfonate as the surfactant. The results revealed that BiOCl nanoplates with thickness below 5 nm and widths of 20~30 nm were uniformly dispersed on the surface of g-C3N4 nanosheets, indicating the formation of a close contact between the BiOCl and g- C3N4. The catalytic activity of the obtained BiOCl/g-C3N4 composite has been evaluated by the degradation process of rhodamine B under visible light irradiation. It has been demonstrated that the catalytic activity of BiOCl/g-C3N4 composite was significantly enhanced compared with the bare component due to the synergistic effect between BiOCl and g-C3N4.
关键词： BiOCl,Nanocomposite,Surfaces,Photocatalyst,g-C3N4
更新于2025-09-23 15:21:01
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Photocatalytic degradation enhancements of dyes with bi-functionalized zones of modified nanoflower like TiO2 with Pt-C3N4 under sunlight irradiation
摘要： In this work, a novel method was proposed to photodegradation of organic dyes as important pollutants in wastewaters of textile industries. A one-step hydrothermal method was used to directly synthesis nanoflower like TiO2 on ordinary glass (OG) and modified with Pt-C3N4 nanotubes (NFs TiO2/Pt-C3N4) via electrophoretic deposition (EPD) method. Its photocatalytic activity investigated for degradation of three dyes under sunlight irradiation. The properties of NFs TiO2/Pt-C3N4 NTs were characterized by SEM, FT-IR, EDS, and XRD. Reduction of band gap energy and improvement of light absorption in the visible region for the modified photocatalyst were evaluated by using Tauc’s plot method. The experimental result showed that the NFs TiO2/Pt-C3N4 NTs achieved degradation efficiency of <97% at 240 min, towards methylene blue (MB), methyl violet (MV) and malachite green (MG) which are higher than pure TiO2 (68%, 83%, and 71%, respectively). Also as a new strategy, a part of the NFs TiO2/Pt-C3N4 NTs was used as a photoanode of the dye-sensitized solar cell (DSSC) and the other part, placed at a solution as a degradation zone. So with this bi-functionalized system, the degradation time was reduced from 240 min to 120 min with the same degradation efficiency.
关键词： Nanoflowers of TiO2,Pt-C3N4 nanotubes,dye-sensitized solar cells,photodegradation,bi-functionalized system
更新于2025-09-23 15:21:01
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Highly Efficient Solara??Catalytic Degradation of Reactive Black 5 Dye Using Mesoporous Plasmonic Ag/ga??C <sub/>3</sub> N <sub/>4</sub> Nanocomposites
摘要： An azo dye, Reactive Black 5 (RB5), was degraded by three photocatalysts of g-C3N4, Ag(2 %)/g-C3N4, and Ag(5 %)/g-C3N4 with the specific surface areas of 34.41, 28.70, and 35.58 m2 g?1 and the band gaps of 2.52, 1.56, and 1.71 eV under sunlight illumination, respectively. The results showed 40 mg/L of g-C3N4 could degrade completely 10 ppm RB5 at pH 3.4 within 10 min under sunlight irradiation with the first-order rate constant of 0.312 min?1. Under the same conditions, the complete degradation time of RB5 reduced to 5 and 7 min when the plasmonic nanocomposites of Ag (2 %)/g-C3N4 and Ag (5 %)/g-C3N4 were used as photocatalysts, respectively. Ag content had an important influence on the photocatalytic activity of g-C3N4 against RB5 so that Ag (2 %)/g-C3N4 possessed the best photocatalytic efficiency with the rate constant of 0.795 min?1. In fact, Ag nanoparticles through the surface plasmon resonance effects and by accepting the photogenerated electrons could improve the visible-light absorption and increase charge separation of g-C3N4. The results showed superoxide radical is the main oxidant in the photodegradation of RB5.
关键词： Surface Plasmon Resonance,Photocatalysis,RB5 dye,Graphitic carbon nitride,Ag/g-C3N4 nanocomposites
更新于2025-09-23 15:19:57
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Post-annealed graphite carbon nitride nanoplates obtained by sugar-assisted exfoliation with improved visible-light photocatalytic performance
摘要： Two-dimensional (2D) graphitic carbon nitride (g-C3N4) nanoplates (CNNP) have become a hot research topic in photocatalysis due to their small thickness and large specific surface area that favors charge transport and catalytic surface reactions. However, the wide application of 2D g-C3N4 nanoplates prepared by ordinary methods suffers from increased band gaps with a poor solar harvesting capability caused by the strong quantum confinement effect and reduced conjugation distance. In this paper, a facile approach of exfoliation and the following fast thermal treatment of the bulk g-C3N4 is proposed to obtain a porous few-layered g-C3N4 with nitrogen defects. Due to the preferable crystal, textural, optical and electronic structures, the as-obtained porous CNNP demonstrated a significantly improved photocatalytic activity towards water splitting than the bulk g-C3N4 and even the 3 nm-thick CNNP obtained by sugar-assisted exfoliation of the bulk g-C3N4. The difference in the enhancement factors between the H2O splitting and organic decomposition has revealed the effect of N defects. This study offers insightful outlooks on the scalable fabrication of a porous few-layered structure with a promoted photocatalytic performance.
关键词： Photocatalytic activity,g-C3N4 nanoplates,Co-grinding,Thermal treatment,Sugar
更新于2025-09-23 15:19:57