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1.
We fabricated novel ternary nanocomposites through integration of C-dots (carbon dots), BiOCl, and nanosheets of graphitic carbon nitride (g-C 3N 4 nanosheets) by a cost-effective route. The fabricated photocatalysts were subsequently characterized by XRD, EDX, TEM, HRTEM, XPS, FT-IR, UV-vis DRS, TGA, BET, and PL methods to gain their structure, purity, morphology, optical, textural, and thermal properties. In addition, the degradation intermediates were identified by gas chromatography-mass spectroscopy (GC-MS). Photocatalytic performance of the synthesized samples was studied by photodegradations of three cationic (RhB, MB, and fuchsine), one anionic (MO) dyes, one colorless (phenol) pollutant and removal of an inorganic pollutant (Cr(VI)) under visible light. It was revealed that the ternary nanocomposite with loading 20% of BiOCl illustrated superlative performances in the selected photocatalytic reactions compared with the corresponding bare and binary photocatalysts. Visible-light photocatalytic activity of the g-C 3N 4 nanosheets/CDs/BiOCl (20%) nanocomposite was 42.6, 27.8, 24.8, 20.2, and 15.9 times higher than the pure g-C 3N 4 for removal of RhB, MB, MO, fuchsine, and phenol, respectively. Likewise, the ternary photocatalyst showed enhanced activity of 15.3 times relative to the g-C 3N 4 in photoreduction of Cr(VI). Moreover, the ternary nanocomposite exhibited excellent chemical stability and recyclability after five cycles. Finally, the mechanism for improved photocatalytic performance was discussed based on the band potential positions. 相似文献
2.
In this contribution, a Z-scheme mesoporous BiVO 4/g-C 3N 4 nanocomposite heterojunction with a considerable surface area and high crystallinity was synthesized by a simple soft and hard template-assisted approach. This material demonstrates superior visible light-driven photocatalysis for the photoreduction of Hg(II) ions. TEM and XRD results show that the mesoporous BiVO 4 NPs, with a monoclinic phase and an ellipsoid-like shape, are highly dispersed onto the porous 2D surfaces of g-C 3N 4 nanosheets with a particle size of 5–10 nm. The obtained BiVO 4/g-C 3N 4 nanocomposites with a p-n heterojunction show significantly enhanced Hg(II) photoreduction efficiency compared to the mesoporous BiVO 4 NPs and pristine g-C 3N 4. Among all synthesized photocatalysts, the 1.2% BiVO 4/g-C 3N 4 nanocomposite indicated the highest photoreduction of Hg(II) performance, reaching ~ 100% within 60 min; this result is 3.9 and 4.5 –fold larger than that of the BiVO 4 NPs and pristine g-C 3N 4. The Hg(II) photoreduction rates highly increase to 208.90, 314.95, 411.23 and 418.68 μmol g −1min −1 for the mesoporous 0.4, 0.8, 1.2 and 1.6% BiVO 4/g-C 3N 4 nanocomposites, respectively. The reduction rate of the mesoporous 1.2% BiVO 4/g-C 3N 4 nanocomposite demonstrated a 5.2 and 3.8 times larger increase than that of the pristine g-C 3N 4 nanosheets and pure BiVO 4 NPs. The superior Hg(II) photoreduction efficiency was ascribed to decreased carrier recombination and the improved utilization of visible light by constructing BiVO 4/g-C 3N 4 nanocomposites with a p-n junction. Transient photocurrent measurement and photoluminescence spectra were employed to confirm the possible Hg(II) photoreduction mechanism over these BiVO 4/g-C 3N 4 photocatalysts. This research provides an accessible route for the nanoengineered design of mesoporous BiVO 4/g-C 3N 4 heterostructures that demonstrated unique photocatalytic performance. 相似文献
3.
Graphitic carbon nitride (g-C 3N 4) has attracted increasing interest as a visible-light-active photocatalyst. In this study, saddle-curl-edge-like g-C 3N 4 nanosheets were prepared using a pellet presser (referred to as g-CN P nanosheets). Urea was used as the precursor for the preparation of g-C 3N 4. Thermal polymerization of urea in a pellet form significantly affected the properties of g-C 3N 4. Systematic investigations were performed, and the results for the modified g-C 3N 4 nanosheets are presented herein. These results were compared with those for pristine g-C 3N 4 to identify the factors that affected the fundamental properties. X-ray diffraction analysis and high-resolution transmission electron microscopy revealed a crystallinity improvement in the g-CN P nanosheets. Fourier-transform infrared spectroscopy provided clear information regarding the fundamental modes of g-C 3N 4, and X-ray photoelectron spectroscopy (XPS) peak-fitting investigations revealed the variations of C and N in detail. The light-harvesting property and separation efficiency of the photogenerated charge carriers were examined via optical absorption and photoluminescence studies. The valence band edge and conduction band edge potentials were calculated using XPS, and the results indicated a significant reduction in the bandgap for the g-CN P nanosheets. The Brunauer–Emmett–Teller surface area increased for the g-CN P nanosheets. The photocatalytic degradation performance of the g-CN P nanosheets was tested by applying a potential and using the classical dye Rhodamine B (RhB). The RhB dye solution was almost completely degraded within 28 min. The rate constant of the g-CN P nanosheets was increased by a factor of 3.8 compared with the pristine g-C 3N 4 nanosheets. The high crystallinity, enhanced light absorption, reduced bandgap, and increased surface area of the saddle-curl-edge-like morphology boosted the photocatalytic performance of the g-CN P nanosheets. 相似文献
4.
In this study, the multifunctional carbon nitride based composite graphitic-C 3N 4 (g-C 3N 4)/TiO 2/Ag was prepared through a simple and efficient vacuum freeze-drying route. TiO 2 and Ag nanoparticles were demonstrated to decorate onto the surface of g-C 3N 4 sheet. In the ultraviolet–visible absorption test, a narrower band gap and red-shift of light absorption edge were observed for g-C 3N 4/TiO 2/Ag compared to pristine g-C 3N 4 and single-component modified g-C 3N 4/TiO 2. The photodegradation property of g-C 3N 4/TiO 2/Ag was investigated toward the degradation of methylene blue (abbreviated as MB) under the irradiation of visible light. These results indicated that the degradation performance of organic dyes for g-C 3N 4/TiO 2/Ag was obviously improved compared with g-C 3N 4/TiO 2 and g-C 3N 4. The reaction rate constant of MB degradation for g-C 3N 4/TiO 2/Ag was 4.24 times higher than that of pristine g-C 3N 4. In addition, such rationally constructed nanocomposite presented evidently enhanced antibacterial performance against the Gram-negative Escherichia coli. Concentration dependent antibacterial performance was systematically investigated. And 84% bacterial cell viability loss had been observed at 500 μg/mL g-C 3N 4/TiO 2/Ag within 2 h visible light irradiation. 相似文献
5.
An effective g-C 3N 4/Fe@ZnO heterostructured photocatalyst was synthesized by a simple chemical co-precipitation method and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and ultraviolet–visible spectroscopy. Transmission electron microscopy revealed that 7-8 nm-sized 1%Fe@ZnO nanoparticles were evenly distributed on g-C 3N 4 nanosheets to form a hybrid composite. The photocatalytic effectiveness of the composites was assessed against methylene blue dye, and it was found that the 50%g-C 3N 4/Fe@ZnO photocatalyst was more efficient in harvesting solar energy to degrade dye than the ZnO, 1%Fe@ZnO, g-C 3N 4, g-C 3N 4/ZnO and (10, 25, 40, 60 & 75 wt%) g-C 3N 4/Fe@ZnO samples. The antibacterial competency of the samples was also explored against Gram-positive ( Bacillus subtilis, Staphylococcus aureus and Streptococcus salivarius) and Gram-negative ( Escherichia coli) bacteria through the well diffusion method. The 50%g-C 3N 4/Fe@ZnO nanocomposite exhibited a superior antibacterial action compared to that of the rest of the samples. The exceptionally improved photocatalytic and antimicrobial efficiency of the 50%g-C 3N 4/Fe@ZnO composite was primarily accredited to the synergic outcome of the interface established between Fe@ZnO nanoparticles and g-C 3N 4 nanosheets. 相似文献
6.
Graphitic carbon nitride (g-C3N4) has received much interest as a visible-light-driven photocatalyst for degrading pollutants such as organic dyes and antibiotics. However, g-C3N4 bulk activity could not meet expectations due to its rapid recombination of photogenerated electron–hole pairs and low specific surface area. In our study, melamine was thermally treated one-step in the presence of NH4Cl to produce g-C3N4 nanosheets. The characterizations of surface morphology and optical properties of all g-C3N4 samples were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrum (XPS), transmission electron microscopy (TEM), and UV–visible diffuse reflectance spectroscopy. Compared to bulk g-C3N4, g-C3N4 nanosheets demonstrated excellent photocatalytic activities, with approximately 98% RhB removal after 210 min of visible light irradiation. Furthermore, the effect of catalyst dosage, pH, and RhB concentration on the removal percentage dye of g-C3N4 nanosheets was also investigated. h+ and ?O2? species were demonstrated as the key reactive species for the RhB. Besides, ECN exposed a tetracycline degradation efficiency of 80.5% under visible-light irradiation for 210 min, which is higher than BCN (60.8%). The improved photocatalytic activity of g-C3N4 nanosheets is due to the restriction of the recombination of photogenerated electrons/hole pairs, as provided by photoluminescence spectra and Nyquist plot. As a result, our research may offer an effective approach to fabricating g-C3N4 nanosheets with high photocatalytic activity and high stability for environmental decontamination. 相似文献
7.
Ceramic-polymeric 3C–silicon carbide-graphitic carbon nitride (3C–SiC@g-C 3N 4) nanocomposites were synthesized by decorating cubic phased, ceramic 3C-Silicon carbide (3C–SiC) on the framework of the nanosheets of metal free polymeric graphitic carbon nitride (g-C 3N 4) by single step pulsed laser ablation in liquid (PLAL) method. Morphological, structural, elemental and optical characterizations of the synthesized 3C–SiC@g-C 3N 4 nanocomposites were carried out. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM) studies confirm the perfect anchoring of 3C–SiC on g-C 3N 4 nanosheets in 3C–SiC@g-C 3N 4 nanocomposites synthesized by PLAL method. Ultra-violet diffuse reflectance spectra (UV-DRS) of 3C–SiC@g-C 3N 4 indicated the enhancement of visible light absorption and also the narrowing down of band gap energy in 3C–SiC@g-C 3N 4 nanocomposites, as a result of the anchoring of 3C–SiC on g-C 3N 4. Also we noticed the decrease of photoluminescence (PL) emission intensities in the PL spectra of 3C–SiC@g-C 3N 4 with respect to pure g-C 3N 4, which indicates the reduced photo-induced charge recombination by the presence of 3C–SiC content on g-C 3N 4 nanosheets. In the application side, PLAL synthesized 3C–SiC@g-C 3N 4 nanocomposites exhibited enhanced visible light driven photocatalytic degradation of methylene blue dye in water, improved antibacterial activity against Pseudomonas aeruginosa (gram-negative) and Staphylococcus aureus (gram-positive) bacteria, and also served as better inhibiting agent for biofilm formation, compared to pure g-C 3N 4 nanosheets. It is quite obvious from our studies that this ceramic-polymeric nanocomposite, 3C–SiC@g-C 3N 4 has the potential application for antibacterial and anti-biofilm activities in addition to its remarkable photocatalytic performance. 相似文献
8.
Graphitic carbon nitride (g-C 3N 4) has been demonstrated as an advanced support material for Pt nanoparticles (NPs) due to its excellent stability and abundant Lewis acid for anchoring metal NPs. However, its non-conductive nature and low surface areas still impede its application in electrochemical fields. Herein, a π–π stacking method is presented to prepare graphene/ultrathin g-C 3N 4 nanosheets composite support for PtRu catalyst. The weaknesses of g-C 3N 4 are greatly overcome by establishing a 2D layered structure. The significantly enhanced performance for this novel PtRu catalyst is ascribed to reasons as follows: the homogeneous dispersion of PtRu NPs on g-C 3N 4 nanosheets due to its abundant Lewis acid sites for anchoring PtRu NPs; the excellent mechanical resistance and stability of g-C 3N 4 nanosheets in acidic and oxidative environments; the increased electron conductivity of support by forming a layered structure and the strong metal-support interaction (SMSI) between metal NPs and g-C 3N 4 NS. 相似文献
9.
In view of the lack of a conformal, load-bearing, lightweight, and high-temperature resistant integrated microwave-absorbing composites for applications under extremely complex conditions, this study successfully applies gel casting craft to porous Si 3N 4 microwave-absorbing composites. The high-temperature decomposition reaction of Ti 3SiC 2 powder was utilized to generate uniform Ti-C x-N 1−x grains in situ and to enhance the mechanical and microwave-absorption properties of porous Ti-C x-N 1−x/Si 3N 4 composites. The bending strength, fracture toughness, density, maximum reflection loss value, absorption bandwidth and matched thickness in P-band of the composite with 30 wt% Ti 3SiC 2 addition were 164.87 ± 7.56 MPa, 2.61 ± 0.13 MPa·m 1/2, 2.077 g/cm 3, 32.42 dB, 1.74 GHz and 4.2 mm, respectively. The fracture toughness and bending strength of the composite were increased by 71.71% and 58.13%, respectively, compared with monolithic porous Si 3N 4. The electromagnetic wave loss mechanisms of the composites are proposed as a combination of conductivity loss, multiple reflections and scattering, interfacial polarization and defect polarization. 相似文献
10.
2D heterojunction based on g-C 3N 4 nanosheets with other semiconductor nanosheets is a promising way to improve photocatalytic hydrogen evolution (PHE) activity over g-C 3N 4. However, current 2D heterojunction based on g-C 3N 4 are unsatisfactory due to their insufficient absorption of visible light and inefficient charge separation. In this work, Ag/TiO 2/g-C 3N 4 nanocomposites based on 2D heterojunction coupling with Ag surface plasmon resonance (SPR) were synthesized by a method combining facile wetness impregnation calcination. The PHE activity of Ag/TiO 2/g-C 3N 4 nanocomposites is attributed to the TiO 2/g-C 3N 4 2D heterojunction and bare g-C 3N 4 nanosheet under visible light irradiation, indicating a cooperative effect between Ag and TiO 2/g-C 3N 4 2D heterojunction. As a result of SPR effect, the composites strongly absorb visible light. In addition, the oscillating hot electrons from Ag can easily transfer to 2D heterojunction. This synergistic effect lead to sufficient visible light absorption and efficient charge separation of 2D heterojunction, which improved the PHE activity of g-C 3N 4. This work indicates that loading metal nanoparticles on 2D heterojunction as metal SPR-2D heterojunction nanocomposites may be a potential method for harvesting visible light for PHE. 相似文献
11.
Surface and bandgap engineering of graphitic carbon nitride (g-C 3N 4) could be vital in enhancing photocatalytic performance by suppressing the recombination rate of photogenerated electron-hole pairs. The present report investigated the doping effects of various wt.% (0.2–5.0%) of gold nanoparticles (Au NPs) to g-C 3N 4 (Au/g-C 3N 4) for the enhancement of the photocatalytic efficiency of g-C 3N 4 nanocomposites. A straightforward and cost-effective synthesis methodology has been applied for the desired nanocomposites. Relevant characterization tools such as XRD, XPS, TEM, FTIR, and UV–Vis were utilized to analyze various physicochemical properties. The TEM images clearly show that spherical Au NPs were homogeneously distributed into the thin carbon nitride graphitic layers, confirming the successful doping of Au. The higher-magnification TEM image confirms that the sizes of the Au NPs varied from 15 to 25 nm. The photoactivity of the newly designed Au/g-C 3N 4 nanocomposites has been evaluated for the degradation of both methylene blue dye and the drug gemifloxacin mesylate, and their efficiencies were compared with that of bare g-C 3N 4. Our findings revealed that Au/g-C 3N 4 nanocomposites with various Au contents had superior photocatalytic activity compared to bare g-C 3N 4. However, the 1%Au/g-C 3N 4 nanocomposite could be considered the optimum photocatalyst, producing 95.13% destruction of the target dye molecule in 90 min, in contrast to the 69% achieved with bare g-C3N4, under the clean energy of visible light illumination. Additionally, the photodegradation rate of the 1%Au/g-C 3N 4 nanocomposite is 2.69 times higher than the rate of bare g-C 3N 4. This report might open a new gateway towards a straightforward and cost-effective synthesis approach for Au/g-C 3N 4 nanocomposites and provides a smooth and robust platform for the utilization of this new nanocomposite for environmental remediation processes. 相似文献
12.
Magnetic/dielectric composites can offer good electromagnetic impendence. However, the strategy for embodying strong absorbing ability and broad effective absorption band simultaneously is a significant challenge. Therefore, assembled porous Fe 3O 4@g-C 3N 4 hybrid nanocomposites have been designed and synthesized, in which porous Fe 3O 4 nanospheres assembled by ~ 3?nm Fe 3O 4 nanoparticles are surrounded by g-C 3N 4. The introduction of g-C 3N 4 improves dielectric loss ability at 2–18?GHz and magnetic loss ability at 2–10?GHz, and enhances attenuation constant, and increases electromagnetic impedance degree. These merits ensure that assembled porous Fe 3O 4/g-C 3N 4 hybrid nanocomposites deliver superior microwave absorption performance, such as effective absorption bandwidth, fE, (reflection loss less ??10?dB) exceeding 5?GHz at 2.0–2.3?mm, the maximal fE of 5.76?GHz and minimal reflection loss of at least ??20?dB with thickness ranging from 2.3 to 10.0?mm, avoiding the sensitivity of absorption properties to absorbing layer thickness. Stable microwave absorbing performance originates from multi-interfacial polarization, multi-reflection, enhanced electromagnetic loss capability, and good electromagnetic impedance. Our study offers a new idea for stable microwave absorber at 2–18?GHz. 相似文献
13.
Gold nanoparticles (Au NPs) were fabricated by laser ablation in liquid (LAL) as a green method and decorated on graphitic carbon nitride (g-C 3N 4) by a facile ultrasonication method. g-C 3N 4 was prepared via urea pyrolysis. The prepared g-C 3N 4/Au (denoted as CN/Au) nanocomposite was characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectrometry (EDS). The synthesized CN/Au nanocomposite was applied as an efficient catalyst in the reduction of 4-nitrophenol (4-NP) and methyl orange (MO) using NaBH 4 at room temperature. The recyclability of CN/Au catalyst was examined. 相似文献
14.
The reasonable modulation of tri- s-triazine structure units of g-C 3N 4 is an effective method to optimize its intrinsic electronic and optical properties, thus boosting its photocatalytic hydrogen-evolution activity. Herein, amino groups are successfully introduced into the tri- s-triazine structure units of g-C 3N 4 nanosheets to improve their H 2-evolution activity via a facile oxalic acid-induced supramolecular assembly strategy. In this case, the resulting amino group-rich porous g-C 3N 4 nanosheets display a loose and fluffy structure with a large specific surface area (70.41 m 2 g ?1) and pore volume (0.50 cm 3? g ??1), and enhanced visible-light absorption (450–800 nm). Photocatalytic tests reveal that the amino group-rich porous g-C 3N 4 nanosheets (AP-CN1.0 nanosheets) exhibit a significantly elevated photocatalytic H 2-production activity (130.7 μmol h ?1, AQE = 5.58%), which is much greater than that of bulk g-C 3N 4 by a factor of 4.9 times. The enhanced hydrogen-generation performance of amino group-rich porous g-C 3N 4 nanosheets can be mainly attributed to the introduction of more amino groups, which can reinforce the visible-light absorption and work as the interfacial hydrogen-generation active centers to boost the photocatalytic hydrogen production. The present facile and effective regulation of tri- s-triazine structure units may provide an ideal route for the exploitation of novel and highly efficient g-C 3N 4 photocatalysts. 相似文献
15.
Hydrogen production by photolysis of water by sunlight is an environmentally-friendly preparation technology for renewable energy. Graphitic carbon nitride (g-C 3N 4), despite with obvious catalytic effect, is still unsatisfactory for hydrogen production. In this work, phosphorus element is incorporated to tune g-C 3N 4's property through calcinating the mixture of g-C 3N 4 and NaH 2PO 2, sacrificial agent and co-catalyst also been supplied to help efficient photocatalytic hydrogen production. Phosphorus (P) doped g-C 3N 4 samples (PCN-S) were prepared, and their catalytic properties were studied. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and ultraviolet diffuse reflection (UV-DRS) were used to study their structures and morphologies. The results show that the reaction rate of PCN-S is 318 μmol h −1 g −1, which is 2.98 times as high as pure carbon nitride nanosheets (CN) can do. Our study paves a new avenue, which is simple, environment-friendly and sustainable, to synthesize highly efficient P doping g-C 3N 4 nanosheets for solar energy conversion. 相似文献
16.
Graphene oxide (GO) membranes have shown great potential for water purification, but their permeability and antipressure ability are poor, which limits their practical applications. In this study, two-dimensional graphitic carbon nitride (g-C 3N 4) nanosheet-intercalated GO (GOCN) membranes were developed to improve the separation performance of GO membranes, especially under high operating pressure. After incorporation of the g-C 3N 4 nanosheets, the amount of permeable nanochannels (wrinkles or corrugation) in the membrane increased; hence, the water permeance was effectively improved (twice as high as that of GO membranes). Moreover, the antipressure performance of the GOCN membranes was significantly enhanced (even below 0.5 MPa pressure) as the nanochannels in the composite membranes become stable and rigid due to the support of the pressure-resistant g-C 3N 4 nanosheets. The good separation performance demonstrates that the intercalation of g-C 3N 4 is an effective strategy to improve the GO-based membrane properties, which can promote their application in water purification. 相似文献
17.
In this paper, a novel g-C 3N 4/2 wt% SnS 2 nanocomposite was successfully synthesized using an in-situ growth of SnS 2 on g-C 3N 4. X-ray diffraction (XRD), atomic force microscopy (AFM), Brunauer-Emmett-Teller (BET) method, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectrometer were used to characterize the photocatalysts. Exploring adsorption behavior, as an importatnt stage during photocatalytic reactions, is of great importance. Hence, both adsorption and photocatalytic performance of the synthesized photocatalysts have been investigated in detail. The adsorption isotherm fittings exhibited that Freundlich and Langmuir-Freundlich models can be applied to the methylene blue (MB) adsorption on the photocatalysts, indicating surface heterogeneity should be considered. A pseudo-second-order model was fitted to explore the adsorption kinetics. According to the observed redshift in the Fourier transform infrared spectroscopy (FTIR) result of g-C 3N 4/SnS 2 nanocomposite, π-π interaction was dominant during MB adsorption. Also, a slight redshift and significant PL intensity reduction in g-C 3N 4/SnS 2 nanocomposite led to 96% photocatalytic efficiency after 180 min under visible light radiation. The kinetics of photodegradation over g-C 3N 4/SnS 2 was about 9 and 3 times higher than those of g-C 3N 4 and SnS 2 photocatalysts, respectively. The superoxide and hydroxyl radicals were the main reactive species in the photocatalytic degradation with a Z-scheme charge transfer mechanism. The g-C 3N 4/SnS 2 nanocomposite was found to be remarkably stable after three consecutive cycles of MB degradation. 相似文献
18.
The development of a graphitic carbon nitride (g-C 3N 4) photocatalyst is of great importance to a variety of visible utilization application fields. The desired high efficiency can be achieved by employing well-controlled g-C 3N 4 nanostructures. In this study, we successfully synthesized high surface area g-C 3N 4 nanowires and nanofibers using a cyanuric chloride and melamine precursor dispersed in a solvothermal reaction and with a subsequent calcination step. The obtained novel nanowire product had a diameter of 10–20 nm and a length of several hundreds of nanometers, while the nanofibers revealed fibrous nanostructures of randomly dispersed fibers with an average diameter of ~15 nm. The adsorption and photocatalytic experimental results indicated that the as-prepared nanowires and nanofibers showed enhanced activities compared with bulk g-C 3N 4. Based on our experimental results, a possible photocatalytic mechanism with hydroxyl and superoxide radical species as the main active species in photocatalysis was proposed. Moreover, our strategy may provide progress toward the design and practical application of 1D g-C 3N 4 nanostructures in the adsorption and photocatalytic degradation of pollutants. 相似文献
19.
Mesoporous g-C 3N 4 nanosheets (MCN) with uniform pore size were utilized to decorate mesoporous TiO 2 spheres (TSs) to form a core-shell heterojunction photocatalyst containing uniform mesopores. Moreover, the mesoporous g-C 3N 4 nanosheets served as shells for composites, in addition to playing a pivotal function for the regulation of the pore structure of the composite. The mesoporous TiO 2@g-C 3N 4 core/shell structure having a uniform pore size exhibited high surface area of ∼134 m 2/g. This coupled material with improved porosity, not only led to increased visible-light absorption but also led to the enhanced charge generation/separation. In addition, it showed a lengthy cycling stability with highly active visible-light efficiency to degrade Rhodamine B (RhB) dye. 相似文献
20.
During the last few years, the ever-increasing development of electronic devices using and/or producing electromagnetic waves has exited the global concern related to the electromagnetic pollution. As a result, based on the transmission line theory, widespread microwave absorbing materials have been architected operating according to their permeability and permittivity to mitigate the pollution and their emerged hazards. At frequencies above 1 GHz, dielectric nanostructures, having more specific surface area, gained the considerable attention due to their salient microwave absorbing characteristics, originated from the enhanced dipole, interfacial, and defect polarization, deduced by Debye relaxation and Maxwell-Wagner model. Among them, two-dimensional (2D) nanostructures are under the spotlight owing to their unique electromagnetic features. Interestingly, g-C 3N 4 nanosheets illustrated salient microwave absorbing properties generated from its special conjugated structure synthesized from a decussate arrangement of nitrogen and carbon. The lone pair electrons and sp2 hybridization develop π→π*, n→π*, and n→σ* transitions enhancing interfacial interactions, bringing its outstanding microwave properties. In this study, a comprehensive perspective ascribed to the defect engineering, doping, compositing, and medium, influencing the microwave absorbing properties of g-C 3N 4 have been scrupulously dissected. More significantly, the main origins behind the observed permeability of this type of materials were essentially discussed. 相似文献
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