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Synthesis of Zr-based MOF nanocomposites for efficient visible-light photocatalytic degradation of contaminants
摘要： A novel ternary complex photocatalyst (UiO-66/g-C3N4/Ag) was fabricated by chemical protonation coating and photodeposition and its physicochemical parameters, crystal morphology, and electrochemical properties characterized using a series of techniques. Proper addition of g-C3N4 and Ag effectively enhanced the separation and mobility of photoinduced charge and improved the visible-light absorption and thereby the catalytic performance. Degradation experiments on target contaminants such as Rhodamine B (RhB) dye and 2,4-dichlorophenoxyacetic acid (2,4-d) showed that the photocatalytic ability of UiO-66/g-C3N4/Ag(15) was greatly increased compared with the parent material. Moreover, the composite could be regenerated by a simple ethanol washing process and exhibited stability and high reusability over six cycles. Finally, experiments on trapping of active species revealed that superoxide radicals (·O2?), holes (h+), and hydroxyl radicals (·OH) were primarily responsible for the photodegradation of RhB and 2,4-d.
关键词： UiO-66/g-C3N4/Ag,Photocatalysis,2,4-d,RhB,Catalytic mechanism
更新于2025-09-23 15:21:21
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A photoelectrochemical glucose and lactose biosensor consisting of gold nanoparticles, MnO2 and g-C3N4 decorated TiO2
摘要： In this study, an innovative light-sensitive hybrid material was used for photoelectrochemical (PEC) biosensor fabrication. Herein, gold nanoparticles modified mesoporous TiO2 was coated on an indium tin oxide substrate, after a layer of MnO2/g-C3N4 was introduced to develop a PEC biosensor that yielded a favorable electronic interface for photo-excited electron injection. Glucose oxidase and β-galactosidase were co-immobilized on the photoanode surface via silane/glutaraldehyde linkage chemistry for glucose and lactose determination. Au NPs, g-C3N4, and MnO2 were utilized to modify quintessential semiconductor TiO2 owing to their narrow band gaps, appropriate position of the valence and conduction bands, and high visible light absorption. The p–n heterojunction formation at the interface of MnO2 and g-C3N4/TiO2 was presumed, and the heterojunction facilitates the charge transport and inhibit the recombination of excited electrons. Direct electron transfer led to the hole scavenging by FADH2, which reinforced the photocurrent. The linear measurement ranges were calculated in the range of 0.004-1.75 mM, with a sensitivity of 1.54 μAmM?1cm?2 for glucose at 0 V, and 0.008-2.50 mM, with a sensitivity of 1.66 μAmM?1cm?2 for lactose at -0.4 V. To the best of our knowledge, we report the first PEC lactose biosensor, and this study opens the door to PEC multianalyte detection.
关键词： β-galactosidase,g-C3N4,Self-powered biosensor,Glucose oxidase,Gold nanoparticles
更新于2025-09-23 15:21:21
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Bio-inspired Z-scheme g-C3N4/Ag2CrO4 for efficient visible-light photocatalytic hydrogen generation
摘要： Due to low charge separation efficiency and poor stability, it is usually difficult for single-component photocatalysts such as graphitic carbon nitride (g-C3N4) and silver chromate (Ag2CrO4) to fulfill photocatalytic hydrogen production efficiently. Z-scheme charge transport mechanism that mimics the photosynthesis in nature is an effective way to solve the above problems. Inspired by photosynthesis, we report Ag2CrO4 nanoparticles-decorated g-C3N4 nanosheet as an efficient photocatalyst for hydrogen evolution reaction (HER) with methanol as sacrificial agent. The formation of Z-scheme g-C3N4/Ag2CrO4 nanosheets photocatalysts could inhibit the recombination of photogenerated electron-hole pairs, promote the generation of hydrogen by photosplitting of water. The experiment results indicate that g-C3N4/Ag2CrO4 nanocomposites present enhanced photocatalytic activity and stability in the H2 evolution of water splitting. And the nanocomposites g-C3N4/Ag2CrO4(23.1%) show the 14 times HER efficiency compared to that of bare g-C3N4.
关键词： visible-light,Z-scheme,hydrogen production,g-C3N4,Ag2CrO4,photocatalysts
更新于2025-09-23 15:21:21
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In-situ fabrication of Ag/P-g-C3N4 composites with enhanced photocatalytic activity for sulfamethoxazole degradation
摘要： A series of Ag/P-g-C3N4 composites with different Ag content were synthesized for the first time by thermal polymerization combined with photo-deposition method. The composites were characterized by X-ray powder diffraction, field emission scanning electron microscope coupled with energy-dispersive X-ray spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectra, N2 absorption-desorption and X-ray photoelectron spectroscopy. Ag was successfully dispersed on the surface of P-g-C3N4. The photocatalytic performance of P-g-C3N4 and Ag/P-g-C3N4 was evaluated by degrading sulfamethoxazole (SMX) under visible light irradiation. In the presence of 5% Ag/P-g-C3N4, 100% of SMX was degraded within 20 min. The enhanced photocatalytic activity of Ag/P-g-C3N4 was attributed to the surface plasmon resonance effect of metallic Ag and Schottky barrier formed on the interface between Ag and P-g-C3N4, which could speed up the generation rate of electrons and holes and inhibit the recombination of photogenerated electron-hole pairs. The radical quenching tests indicated that holes and superoxide radicals were the dominant active species involved in SMX degradation. The synthesized materials maintained high catalytic activity after five cycle runs. The concentration and the intermediates during the degradation process were determined by LC-MS/MS, and the tentative degradation pathways of SMX in photocatalytic system were proposed.
关键词： sulfamethoxazole,Ag/P-g-C3N4,intermediate,photocatalytic degradation,degradation pathways
更新于2025-09-23 15:21:21
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An Investigation into the Stability of Graphitic C <sub/>3</sub> N <sub/>4</sub> as a Photocatalyst for CO <sub/>2</sub> Reduction
摘要： The increasing CO2 concentration in the atmosphere exerts a significant influence on global warming and climate change. The capture and utilization of CO2 by conversion to useful products is an area of active research. In this work, the photo-driven reduction of CO2 was investigated using graphitic carbon nitride (g-C3N4) as a potential photocatalyst. The photocatalytic reduction of CO2 was investigated with g-C3N4 powder immobilized on a glass support in a batch gas phase photoreactor. The experiments were carried out under UV-Vis irradiation at 70°C and an initial pressure of 2.5 bar. The only gas phase product detected during the irradiation of the g-C3N4 in the presence of CO2 was CO, and the rate of production was observed to decrease over time. Oxygen doped g-C3N4 was also tested for CO2 reduction but had lower efficiency that the parent g-C3N4. Repeated cycles of photocatalytic CO2 reduction showed a decline in the activity of the g-C3N4. In the absence of CO2 some CO generation was also observed. Characterization of used and unused materials, using FTIR and XPS, showed an increase in the oxygen functional groups following UV-Vis irradiation or thermal treatment. While others report the use of g-C3N4 as a photocatalyst, this work highlights the important need for replicates and control testing to determine material stability.
关键词： CO2 reduction,photocatalysis,oxygen doping,graphitic carbon nitride,material stability,g-C3N4
更新于2025-09-23 15:21:21
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Bimetallic PtNi/g-C3N4 nanotubes with enhanced photocatalytic activity for H2 evolution under visible light irradiation
摘要： Bimetallic PtNi-decorated graphitic carbon nitride (g-C3N4) nanotubes were prepared through calcining the mixture of urea and thiourea in the presence of Pluronic F127, followed by deposition of bimetallic PtNi nanoparticles (NPs) via chemical reduction. It is found that the photocatalytic activity of PtNi/g-C3N4 nanotubes is strongly dependent on the molar ratio of Pt/Ni and the highest activity is observed for Pt1Ni1/g-C3N4. Under visible light (l > 420 nm) irradiation, the H2 generation rate over Pt1Ni1/g-C3N4 nanotubes is 104.7 mmol h?1 from a triethanolamine (10 vol%) aqueous solution, which is higher than that of Pt/g-C3N4 nanotubes (98.6 mmol h?1) and is about 47.6 times higher than that of pure g-C3N4 nanotubes. The cyclic photocatalytic reaction indicates that our Pt1Ni1/g-C3N4 nanotubes function as a stable photocatalyst for visible light-driven H2 production. The effect of bimetallic PtNi NPs in the transfer and separation of photogenerated charge carriers occurring in the excited g-C3N4 nanotubes was investigated by performing photoelectrochemical and photoluminescence measurements. Our results reveal that bimetallic PtNi could replace Pt as a promising cocatalyst for photocatalytic H2 evolution with better performance and lower cost.
关键词： Hydrogen evolution,g-C3N4,Nanotube,Bimetallic PtNi,Photocatalyst
更新于2025-09-23 15:21:21
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Insight into the Z-scheme heterostructure WO3/g-C3N4 for enhanced photocatalytic degradation of methyl orange
摘要： WO3 nanosheets and its hybridized nanocomposite, WO3/g-C3N4, were prepared by a simple direct precipitation method. The as-prepared WO3/g-C3N4 showed enhanced photocatalytic activity toward degrading methyl orange (MO). The ?O2 ?, which played key role in the photocatalytic oxidation process, were clearly identified and quantitationally determined by the trapping experiment and nitroblue tetrazolium (NBT) probing method. Z-scheme photocatalytic mechanism was proposed accordingly.
关键词： photocatalysis,WO3/g-C3N4,Nanocomposites,Semiconductors
更新于2025-09-23 15:21:21
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Visible-light degradation of sulfonamides by Z-scheme ZnO/g-C3N4 heterojunctions with amorphous Fe2O3 as electron mediator
摘要： ZnO grafted amorphous Fe2O3 matrix (ZnO/Fe2O3) was coupled with g-C3N4 to synthesize heterojunction photocatalysts with a loosened multilayered structure. The ZnO/Fe2O3/g-C3N4 exhibited enhanced photocatalytic performance in the degradation of sulfamethazine under visible-light irradiation (λ > 420 nm), with an optimum photocatalytic degradation rate approximately 3.0, 2.4 times that of pure g-C3N4 and binary ZnO/g-C3N4. Moreover, the target sulfonamides spiked in actual surface water samples could be efficiently photodegraded by ZnO/Fe2O3/g-C3N4 after 8 h of irradiation, demonstrating its practical potential. An amorphous Fe2O3-mediated Z-scheme mechanism was proposed for the charge transfer at the heterojunction surface, which involved a Fe(III)/Fe(II) oxidation-reduction center that favored the retarded charge recombination and improved photocatalytic activity. Such a mechanism was well supported by the direct detection of surface generated ·O2? and ·OH reactive species. Finally, detailed transformation pathways were proposed based on the photodegradation products identified by QToF-MS analyses. This work provides an illustrative strategy for developing efficient Z-scheme photocatalysts for water purification, by taking advantage of amorphous Fe-based oxides in the semiconductor lattice matching.
关键词： Sulfonamides degradation,Z-scheme mechanism,Electron mediator,ZnO/Fe2O3/g-C3N4,Degradation pathways
更新于2025-09-23 15:21:21
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Defect engineered mesoporous 2D graphitic carbon nitride nanosheet photocatalyst for Rhodamine B degradation under LED light illumination
摘要： In this work, a nitrogen vacancy induced 2D mesoporous graphitic carbon nitrogen (g-C3N4) nanosheet photocatalyst was successfully synthesized through a simple two step thermal treatment method. The morphology of the nanosheet photocatalyst and the presence of nitrogen vacancy was explored through a wide range of characterization techniques. The as prepared photocatalyst possess an improved visible light absorption efficiency as confirmed from the UV-Visible diffuse reflectance spectroscopy (DRS). Moreover, the improved charge carrier separation efficiency of the nitrogen vacant material was demonstrated from the photoluminescence spectrum. Most importantly, the photocatalyst exhibited an excellent photodegradation efficiency towards rhodamine B (RhB) dye under the illumination of an 18 W LED light. The vacancy induced nanosheets demonstrated a degradation co-efficient of 0.074 min-1 in RhB degradation, which is 9.25 fold higher than that of the bulk g-C3N4. The nanosheets further exhibited an enhanced degradation efficiency toward tetracycline antibiotic. Furthermore, the photocatalyst displayed an outstanding stability even after 5 cycles. A plausible photocatalytic mechanism has also been explained based on the results obtained from the radical scavenging experiments. This study would provide insight into the defect induction mechanism into the 2D g-C3N4 nanosheet and expected to help in rationally designing vacancy induced materials with cost effective application in various environmental fields.
关键词： nitrogen vacancy,LED light irradiation,rhodamine B,mesoporous,2D g-C3N4 nanosheet
更新于2025-09-23 15:21:01
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One-pot fabrication of mesoporous g-C3N4/NiS co-catalyst counter electrodes for quantum-dot-sensitized solar cells
摘要： The nickel sulfide (NiS) nanoparticles were anchored on the mesoporous graphitic carbon nitride (g-C3N4) by one-pot calcination with sulfur powder as sulfur source and pore-forming agent. It is the first attempt to use the g-C3N4/NiS as a counter electrode (CE) for quantum-dot-sensitized solar cells. The g-C3N4/NiS co-catalyst based on 0.74 wt% NiS loading for Sn2- reduction obtained a low interface charge transfer resistance (Rct) of 1.08 Ω. The power conversion efficiency of the QDSSC assembled with ZnSe/CdS/CdSe/ZnSe-sensitized TiO2 photoanode and g-C3N4/NiS CE is up to 5.64%, which is 3.05 times as high as that of pure g-C3N4 CE. The enhancement of cell efficiency is attributed to the synergistic effects of excellent morphology of g-C3N4 and its co-catalysis with NiS nanoparticles. The mesoporous architecture contributes a large specific surface area and fast electrolyte transfer channels, and the coupling of g-C3N4 with NiS promotes the transfer of charge between the interface g-C3N4/NiS and electrolytes. The presented strategy for fabricating mesoporous architecture with g-C3N4/NiS uses low-cost raw materials and a simple preparation method, which provides a feasible route to enhance the electrocatalytic activity of g-C3N4.
关键词： g-C3N4/NiS,electrocatalytic activity,mesoporous architecture,counter electrode,quantum-dot-sensitized solar cells
更新于2025-09-23 15:21:01