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A direct one-step synthesis of ultrathin g-C3N4 nanosheets from thiourea for boosting solar photocatalytic H2 evolution
摘要： Two-dimensional (2D) graphitic carbon nitride (g-C3N4) nanosheets, as the promising photocatalyst with fascinating properties, have become a 'rising star' in the field of photocatalysis. Although g-C3N4 nanosheets exfoliated from the bulk g-C3N4 powders are extensively emerged, developing a simple synthetic approach is still full of challenge. To this end, here we report a direct polymerization strategy to fabricate the ultrathin g-C3N4 nanosheets, that is only heating treatment of thiourea in air without addition of any template. The photocatalytic activities of as-prepared samples were evaluated by photoreduction of water to hydrogen (H2) using triethanolamine as sacrificial agent and Pt as co-catalyst under visible-light irradiation (λ > 420 nm). As a result, our few-layered g-C3N4 nanosheets with an average thickness of 3.5 nm exhibit a superior visible-light photocatalytic H2 evolution rate (HER) of 1391 μmol g?1 h?1 and a remarkable apparent quantum efficiency of 6.6% at 420 nm. Eventually, the HER of as-fabricated ultrathin g-C3N4 nanosheets is not only much higher than the dicyandiamide-derived g-C3N4 or melamine-derived g-C3N4, but also greater than the thermal-oxidation etched g-C3N4 nanosheets under the same condition.
关键词： g-C3N4 nanosheets,Template-free polymerization,Solar energy conversion,2D materials,Photocatalysis,One-step synthesis
更新于2025-11-14 17:03:37
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Novel PtPd alloy nanoparticle-decorated g-C3N4 nanosheets with enhanced photocatalytic activity for H2 evolution under visible light irradiation
摘要： PtPd bimetallic alloy nanoparticle (NP)-modified graphitic carbon nitride (g-C3N4) nanosheet photocatalysts were synthesized via chemical deposition precipitation. Characterization of the photocatalytic H2 evolution of the g-C3N4 nanosheets shows that it was significantly enhanced when PtPd alloy NPs were introduced as a co-catalyst. The 0.2 wt% PtPd/g-C3N4 composite photocatalyst gave a maximum H2 production rate of 1600.8 μmol g–1 h–1. Furthermore, when K2HPO4 was added to the reaction system, the H2 production rate increased to 2885.0 μmol g–1 h–1. The PtPd/g-C3N4 photocatalyst showed satisfactory photocatalytic stability and was able to maintain most of its photocatalytic activity after four experimental photocatalytic cycles. In addition, a possible mechanism for the enhanced photocatalytic activity was proposed and verified by various photoelectric techniques. These results demonstrate that the synergistic effect between PtPd and g-C3N4 helps to greatly improve the photocatalytic activity of the composite photocatalyst.
关键词： H2 evolution,PtPd alloy nanoparticles,Photocatalysis,g-C3N4 nanosheets
更新于2025-11-14 17:03:37
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2D visible-light-driven TiO2@Ti3C2/g-C3N4 ternary heterostructure for high photocatalytic activity
摘要： A novel 2D visible-light-driven TiO2@Ti3C2/g-C3N4 ternary heterojunction photocatalyst with modified interfacial microstructure and electronic properties was synthesized by ultrasonic-assisted calcination method. The remarkably active g-C3N4 could provide high productivity of photogenerated electrons and holes. Meanwhile, the O/OH-terminated Ti3C2 and by-product TiO2 could act as excellent supporters by migrating electrons in TiO2@Ti3C2/g-C3N4 hybrids. As a result, the highest photocatalytic activities in the degradation of aniline and RhB were increased to 5 and 1.33 times higher than that of pristine g-C3N4 under visible-light irradiation, respectively. Furthermore, we proposed that n–n heterojunction and n-type Schottky heterojunction were built up across their interfaces, which efficiently improve the transition of electrons and further promote the photocatalytic activity of TiO2@Ti3C2/g-C3N4 hybrids. More appealingly, all the results highlight that the environment-friendly TiO2@Ti3C2/g-C3N4 heterojunction hybrids would be desirable candidates for pollutants degradation.
关键词： 2D materials,photocatalytic activity,TiO2@Ti3C2/g-C3N4,ternary heterojunction,pollutants degradation,visible-light-driven
更新于2025-11-14 17:03:37
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Acetylene black quantum dots as a bridge for few-layer g-C3N4/MoS2 nanosheet architecture: 0D–2D heterojunction as an efficient visible-light-driven photocatalyst
摘要： Great progress has been made based on photocatalytic theory research in the past few years. There is, however, still a long way to go to popularize the application of photocatalytic materials. Here, we introduce a simple synthetic 0D–2D (D: dimensional) heterogeneous material with more efficient photocatalytic degradation. We construct acetylene black (AB) as a bridge to connect a graphitic carbon nitride (g-C3N4) nano-layer and two-dimensional MoS2 sandwich structure based on a simple hydrothermal synthesis and ultrasonic chemical loading. Loading 1% AB onto 2D g-C3N4/(x%)MoS2 not only accelerates the transfer of charge, but also reduces electron–hole recombination, which increases the photocatalytic efficiency per unit time. Studies have shown that the degradation rate of the ternary g-C3N4/AB/3.1%MoS2 catalytic materials can reach 94.29%, which is obviously higher than that of the pure g-C3N4 (80%) or MoS2 (51.74%) in degradation of methyl blue within 130 min. In this work, the ternary heterogeneous catalyst realizes the complementary characteristics between materials, broadens the photocatalytic properties and accelerates the degradation rate of pollutants, and provides a feasible solution to environmental friendliness.
关键词： Graphitic carbon nitride,Ternary photocatalyst,Photocatalytic degradation,QDs/g-C3N4/MoS2
更新于2025-11-14 15:32:45
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Visible-light-driven g-C3N4/Cu2O heterostructures with efficient photocatalytic activities for tetracycline degradation and microbial inactivation
摘要： g-C3N4/Cu2O composites were successfully synthesized by a facile chemical precipitation method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and UV diffuse reflectance spectroscopy (UV-DRS) techniques were employed to characterize the as-synthesized photocatalysts. The photocatalytic experiments indicated that the g-C3N4/Cu2O composites displayed higher photodegradation activity of tetracycline (TC) and inactivation efficiencies of Escherichia coli (E. coli) as well as Fusarium graminearum (F. graminearum) in comparsion with bare g-C3N4 and Cu2O under visible light irradiation. Photoluminescence (PL) spectra implied that the heterojunction between g-C3N4 and Cu2O could efficiently promote the separation efficiency of photo-induced charge carriers. Active species trapping experiment and electron spin resonance (ESR) analysis revealed that ?O2-, ?OH and h+ played important roles in the photocatalytic process. This study could provide new insights into the design of multifunctional g-C3N4-based photocatalysts for environmental purification.
关键词： inactivation mechanism,tetracycline,heterostructures,photocatalysis,g-C3N4/Cu2O
更新于2025-11-14 15:29:11
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Insights into the improved photocatalytic performance of fluorine surface modified mpg-C3N4 at room temperature under aqueous conditions
摘要： A novel fluorine surface modified mesoporous carbon nitride (mpg-C3N4) photocatalysts were synthesized by etching SiO2 with NH4HF2. The mechanism of formation and the factors that affect its photocatalytic activity were investigated. Interestingly, the introduction of F atoms improves the performance of surface state and widens the energy band gap of surface-modified mpg-C3N4 due to the higher separation and efficient mobility of the photoinduced carriers. Consequently, the fluorine-modified mpg-C3N4 exhibits higher carrier lifetime (8.64 ns) than mpg-C3N4 (7.14 ns), which improves the photocatalytic efficiency under ultraviolet light. The enhanced photocatalytic activity was evaluated by studying the degradation experiments of Rhodamine B. It is expected that the present fluorine modification at the surface of mpg-C3N4 may provide new insights in basic research and energy conversion.
关键词： fluorine surface modification,mpg-C3N4,room temperature,photocatalyst
更新于2025-11-14 15:28:36
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Construction of dual defect mediated Z-scheme photocatalysts for enhanced photocatalytic hydrogen evolution
摘要： The construction of Z-scheme system is a promising approach for photocatalytic hydrogen evolution (PHE). In this study, we fabricated a direct Z-scheme system consisting of defect-rich g-C3N4 nanosheets (DR-CNNS) crumpled nanosheets with defect-rich TiO2 (DR-TiO2) nanoparticles via a dual defective strategy. The optimized dual-defective rich TiO2/CNNS composite showed a superior PHE rate of ?651.79 μmol/h with a turnover frequency of ?419.3 h?1 as well as high stability and recyclability, which presented the highest value in single defective TiO2 or g-C3N4-based photocatalysts families reported previously. Furthermore, this protocol could also be extended to synthesize other dual defective g-C3N4/oxides (ZnO, SnO2, etc.) heterostructures. The improved photocatalytic performances could be ascribed to the following aspects: (1) rich dual defect, narrowing the band gap and providing more reactive sites for PHE; (2) intimate interface, facilitating interfacial migration and utilization of photogenerated charges; (3) Z-scheme structure, accelerating photogenerated electron-hole pair separation and thus leading to more e?cient PHE. Our work highlights the critical role of defects in construction of Z-scheme system and provides the possibility of utilizing dual defective g-C3N4-based systems for other photocatalytic applications including CO2 reduction and water puri?cation.
关键词： Photocatalytic hydrogen evolution,Dual defect,Oxides/g-C3N4,Heterojunction,Direct Z-scheme
更新于2025-11-14 15:27:09
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Impact of doped metals on urea-derived g-C3N4 for photocatalytic degradation of antibiotics: Structure, photoactivity and degradation mechanisms
摘要： Metal doping is an appealing modification strategy of graphitic carbon nitride (g-C3N4) to improve its photocatalytic activity. The interactions of g-C3N4 precursors with metals, however, has often been underappreciated, which can induce great impacts on g-C3N4 formation and properties. Herein, the impacts of metals (Na, K, Ca, Mg) on the morphology, structure, and photoactivity of urea-derived g-C3N4 were investigated. Our TEM and XPS results confirmed that the interactions of doped metals with urea precursors lead to the incorporation of O atoms from urea molecules into the framework of g-C3N4. Due to the synergistic effects of the metals and structural O atoms, doped g-C3N4 performed an elevated photodegradation of antibiotics under the visible light irradiation, which was attributed to the enhanced light-harvesting and reduced charge recombination. In addition, the doped metals presented uneven regulation on the band structures and morphology of g-C3N4. As a result, both superoxide and hydroxyl radicals were generated by g-CN-Na and g-CN-K, whereas, only superoxide radicals were involved in g-CN, g-CN-Ca and g-CN-Mg. Consequently, diversified photodegradation mechanisms for enrofloxacin (ENR) were observed that the g-CN, g-CN-Ca and g-CN-Mg reaction systems mainly attacked the piperazine moiety of ENR while g-CN-Na and g-CN-K provided additional photodegradation pathway by attacking quinolone core of ENR. The present work could provide new insights into further understanding of doping chemistry with g-C3N4.
关键词： Metal doping,Photocatalytic degradation of antibiotics,g-C3N4,Visible light photocatalysis
更新于2025-11-14 15:24:45
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Precursor-reforming strategy induced g-C3N4 microtubes with spatial anisotropic charge separation established by conquering hydrogen bond for enhanced photocatalytic H2-production performance
摘要： Precursor-reforming strategy induced graphitic carbon nitride (g-C3N4) with different morphologies for enhanced photocatalytic hydrogen (H2) evolution activity is highly desirable. Herein, g-C3N4 microtubes (mg-C3N4) with adjustable closure degree of microtube orifice and spatial anisotropic charge separation are established by conquering hydrogen bond during thermally exfoliate precursor. Compared to the bulk g-C3N4 (bg-C3N4) and ultrathin g-C3N4 (ug-C3N4), the tubular structure endows mg-C3N4 with spatial anisotropic charge separation that accelerates transfer of charge carriers. As expected, the photocatalytic H2 evolution (PHE) activity of mg-C3N4 has been obviously enhanced. Particularly, the mg-C3N4-24 shows the best PHE activity (957.9 μmol h-1g-1), which is over 18.72 and 3.77 times higher than the bg-C3N4 and ug-C3N4, respectively. In addition, selective photo-deposition experiment results reveal a charge carriers migration behavior that photoproduction electrons migrate to the outer shell and holes prefer to move onto the inner shell of mg-C3N4, thus achieving efficient spatial anisotropic charge separation. We firmly believe that the work presents significant advancement for the design of other materials by precursor-reforming strategy.
关键词： Charge carriers,Precursor-reforming,mg-C3N4,Spatial anisotropic,PHE
更新于2025-11-14 15:23:50
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Synthesis of novel Mn-doped Fe2O3 nanocube supported g-C3N4 photocatalyst for overall visible-light driven water splitting
摘要： A novel Mn-doped Fe2O3 modified g-C3N4 nanosheets composite has been prepared for overall water splitting. Structure characterizations reveal that the Mn are successfully doped in the Fe2O3 nanoparticle and a close interface between g-C3N4 and Mn-doped Fe2O3is obtained. The optimized FMC-10 photocatalyst has a H2 evolution of 51 μmol h?1. The improved photocatalytic performance can be ascribed to the synergy effect of both Mn-doped Fe2O3and g-C3N4. Doping Fe2O3 with Mn promotes photo-induced charges and increases the charge transfer for the improved conductivity of the bulk Fe2O3, while favorable contacting with g-C3N4 enhances the charge separation ability.
关键词： Mn doped,Pure water splitting,g-C3N4,Fe2O3
更新于2025-11-14 15:15:56