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1.
Ag 2WO 4/g-C 3N 4 composites with different Ag 2WO 4 concentration and calcination temperature were synthesized via a mixing and heating approach. Various techniques were used to investigate the characters of the as-prepared samples, such as thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and photoluminescence spectroscopy. The degradation of rhodamine B (20 ppm) under visible light was performed to investigate the photocatalytic activity of Ag 2WO 4/g-C 3N 4 composites. Results indicate that the Ag 2WO 4/g-C 3N 4 is actually Ag/Ag 2WO 4/g-C 3N 4 ternary system. 7.5 wt% Ag 2WO 4/g-C 3N 4 prepared at 300 °C presented the best photocatalytic performance in rhodamine B degradation. The degradation rate reaches 0.0679 min ?1, which is 3.25 times higher than the value of pure g-C 3N 4. The enhanced activity is attributed to the synergetic effect of Ag 2WO 4, g-C 3N 4 and metal Ag. Additionally, cycling experiments also proved that the Ag 2WO 4/g-C 3N 4 photocatalyst has good stability. 相似文献
2.
Highly efficient visible-light-driven heterojunction photocatalysts, spindle-shaped nanoporous TiO 2 coupled with graphitic g-C 3N 4 nanosheets have been synthesized by a facile one-step solvothermal method. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption-desorption analysis and UV–vis diffuse reflectance spectrometry (DRS), proving a successful modification of TiO 2 with g-C 3N 4. The results showed spindle-shaped nanoporous TiO 2 microspheres with a uniform diameter of about 200 nm dispersed uniformly on the surface of graphitic g-C 3N 4 nanosheets. The g-C 3N 4/TiO 2 hybrid materials exhibited higher photocatalytic activity than either pure g-C 3N 4 or nanoporous TiO 2 towards degradation of typical rhodamine B (RhB), methyl blue (MB) and methyl orange (MO) dyes under visible light (>420 nm), which can be largely ascribed to the increased light absorption, larger BET surface area and higher efficient separation of photogenerated electron–hole pairs due to the formation of heterostructure. In addition, the possible transferred and separated behavior of electron–hole pairs and photocatalytic mechanisms on basis of the experimental results are also proposed in detail. 相似文献
3.
Ag/g-C 3N 4 photocatalysts were synthesized by a rapid microwave-assisted polyol process. The characterization results showed monodisperse Ag nanoparticles with diameters of a few nanometers closely attached to the edges of g-C 3N 4. The presence of Ag nanoparticles in Ag/g-C 3N 4 photocatalysts enhanced the visible-light absorption and suppressed the recombination of photogenerated electron/hole pairs. The Ag/g-C 3N 4 photocatalysts exhibited the superior visible-light responsive photocatalytic activity for rhodamine B degradation. The mechanism of visible-light induced photocatalysis over Ag/g-C 3N 4 photocatalysts was also discussed. 相似文献
4.
The g-C3N4 nanosheet was prepared by calcination method, the MoS2 nanosheet was prepared by hydrothermal method. The g-C3N4/MoS2 composites were prepared by ultrasonic composite in anhydrous ethanol. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible spectroscopy, and photoluminescence techniques were used to characterize the materials. The photocatalytic degradation of Rhodamine B (Rh B) by g-C3N4/MoS2 composites with different mass ratios was investigated under visible light. The results show that a small amount of MoS2 combined with g-C3N4 can significantly improve photocatalytic activity. The g-C3N4/MoS2 composite with a mass ratio of 1:8 has the highest photocatalytic activity, and the degradation rate of Rh B increases from 50 to 99.6%. The main reason is that MoS2 and g-C3N4 have a matching band structure. The separation rate of photogenerated electron–hole pairs is enhanced. So the g-C3N4/MoS2 composite can improve the photocatalytic activity. Through the active material capture experiment, it is found that the main active material in the photocatalytic reaction process is holes, followed by superoxide radicals. 相似文献
5.
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
6.
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
7.
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
8.
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
9.
In this study, the coupled photocatalysts ZnS/WO 3 were synthesized by a simple co-precipitation method, varying the content of ZnS (1, 5, and 10 wt%). The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy coupled to energy dispersive spectroscopy (SEM-EDS), N 2 physisorption, UV–Vis with diffuse reflectance spectroscopy (DRS), atomic absorption (AAS), infrared (IR), and photoluminescence (PL) spectroscopies. Furthermore, the synthesized photocatalysts were evaluated on the photocatalytic degradation of sulfamethoxazole (SMX) under simulated sunlight. The activity of the different coupled photocatalysts ZnS/WO 3 was significantly improved compared to the individual semiconductors (ZnS and WO 3). This enhancement was attributed to the reduced recombination rate determined through PL analysis. The ZnS 5%/WO 3 photocatalyst exhibited the highest performance in comparison with the other coupled materials, achieving complete SMX degradation in 60 min. In combination, the enhanced specific surface area, high particle dispersion, and reduced recombination rate define the ZnS 5%/WO 3 photocatalyst as a suitable candidate for photocatalytic environmental applications. 相似文献
10.
The fabrication of nanocomposite photocatalytsts with excellent photocatalytic activity is an important step in the improved degradation of organic dyes. A series of nanocomposite photocatalysts was synthesized with g-C 3N 4 and ZnO loading contents of 10, 20 and 30%. The nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). The optical band gaps of g-C 3N 4, ZnO and ZnAl 2O 4 were about 2.79, 3.21 and 3.55 eV, respectively. Methylene blue (MB) was degraded over the prepared photocatalysts under UV irradiation. Photocatalytic activity was about 9.1 and 9.6 times higher, respectively, on 20%g-C 3N 4/ZnAl 2O 4 and 20%ZnO/ZnAl 2O 4 nanocomposite photocatalysts than on pure ZnAl 2O 4 spinel powders. Recycling experiments showed that 20%g-C 3N 4/ZnAl 2O 4 and 20%ZnO/ZnAl 2O 4 nanocomposite photocatalysts exhibited good stability after five cycles of use. 相似文献
11.
As a potential material applied in the photocatalytic field, graphitic carbon nitride (g-C 3N 4) has attracted extensive attention for its advantages of visible-light response, excellent thermodynamic, and chemical stability. However, the photocatalytic performance of g-C 3N 4 is still limited in practical applications. Here, using a facile thermal polymerization method, unique W-doped foam g-C 3N 4 was synthesized to realize enhanced photocatalytic performance for the degradation of Rhodamine B and the evolution of hydrogen. Compared with pure foam g-C 3N 4, tungsten doping modified the foam g-C 3N 4 and efficiently improved its specific surface area, leading to enhanced photocatalytic performance. The average rate of hydrogen evolution was as high as 8818 μmol·h −1·g −1, which was better than most photocatalysts. This work proposes a new effective method and idea to modify g-C 3N 4 for improving its photocatalytic performance. 相似文献
12.
The nanocomposites of WO 3 nanoparticles and exfoliated graphitized C 3N 4 (g-C 3N 4) particles were prepared and their properties were studied. For this purpose, common methods used for characterization of solid samples were completed with dynamic light scattering (DLS) method and photocatalysis, which are suitable for study of aqueous dispersions.The WO 3 nanoparticles of monoclinic structures were prepared by a hydrothermal method from sodium tungstate and g-C 3N 4 particles were prepared by calcination of melamine forming bulk g-C 3N 4, which was further thermally exfoliated. Its specific surface area (SSA) was 115 m 2 g −1.The nanocomposites were prepared by mixing of WO 3 nanoparticles and g-C 3N 4 structures in aqueous dispersions acidified by hydrochloric acid at pH = 2 followed by their separation and calcination at 450 °C. The real content of WO 3 was determined at 19 wt%, 52 wt% and 63 wt%. It was found by the DLS analysis that the g-C 3N 4 particles were covered by the WO 3 nanoparticles or their agglomerates creating the nanocomposites that were stable in aqueous dispersions even under intensive ultrasonic field. Using transmission electron microscopy (TEM) the average size of the pure WO 3 nanoparticles and those in the nanocomposites was 73 nm and 72 nm, respectively.The formation of heterojunction between both components was investigated by UV–Vis diffuse reflectance (DRS) and photoluminescence (PL) spectroscopy, high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), photocatalysis and photocurrent measurements. The photocatalytic decomposition of phenol under the LED source of 416 nm identified the formation of Z-scheme heterojunction, which was confirmed by the photocurrents measurements. The photocatalytic activity of the nanocomposites decreased with the increasing content of WO 3, which was explained by shielding of the g-C 3N 4 surface by bigger WO 3 agglomerates. This study also demonstrates a unique combination of various characterization techniques working in solid and liquid phase. 相似文献
13.
In this work, cobalt phosphide (CoP) nanoparticles were successfully decorated on an ultrathin g-C 3N 4 nanosheet photocatalysts by in situ chemical deposition. The built-in electric field formed by heterojunction interface of the CoP/g-C 3N 4 composite semiconductor can accelerate the transmission and separation of photogenerated charge-hole pairs and effectively improve the photocatalytic performance. TEM, HRTEM, XPS, and SPV analysis showed that CoP/g-C 3N 4 formed a stable heterogeneous interface and effectively enhanced photogenerated electron-hole separation. UV-vis DRS analysis showed that the composite had enhanced visible light absorption than pure g-C 3N 4 and was a visible light driven photocatalyst. In this process, NaH 2PO 2 and CoCl 2 are used as the source of P and Co, and typical preparation of CoP can be completed within 3 hours. Under visible light irradiation, the optimal H 2 evolution rate of 3.0 mol% CoP/g-C 3N 4 is about 15.1 μmol h −1. The photocatalytic activity and stability of the CoP/g-C 3N 4 materials were evaluated by photocatalytic decomposition of water. The intrinsic relationship between the microstructure of the composite catalyst and the photocatalytic performance was analyzed to reveal the photocatalytic reaction mechanism. 相似文献
14.
Recently, there has been a significant interest in developing high-performance photocatalysts for removing organic pollutants from water environment. Herein, a ternary graphitic C 3N 4 (g-C 3N 4)/Ag 3PO 4/AgBr composite photocatalyst is synthesized using an in-situ precipitation-anion-exchange process and characterized by several spectroscopic and microscopic techniques. During the photocatalytic reaction, X-ray photoelectron spectroscopy clearly illustrated the formation of metallic Ag on the g-C 3N 4/Ag 3PO 4/AgBr composite surface. The ternary composite photocatalyst demonstrated an increased photoactivity under visible light (>420 nm), achieving a complete decolorization of methyl orange (MO) in 5 min. The ternary g-C 3N 4/Ag 3PO 4/AgBr hybrid was also applied to the 2-chlorophenol degradation under visible light, further confirming its excellent photocatalytic activity. In addition, quenching experiments revealed that holes (h +) and O 2?– were the major attack species in the decolorization of MO. The enhanced photoactivity of g-C 3N 4/Ag 3PO 4/AgBr results from the efficient transfer/separation of photoinduced charges with the dual Z-scheme pathway and the charge recombination sites on the formed Ag particles. 相似文献
15.
Photocatalytic technology is an environmentally safe method of eliminating organic pollutants and antibiotics in wastewater. In this research, the performance of Fe 3O 4/CdS/g-C 3N 4 (FCN) photocatalyst for degradation of antibiotics was studied. The composite photocatalysts with different concentrations of g-C 3N 4 were prepared. FCN has better photocatalytic activity than degradation dyes in removal of antibiotics under visible light. This indicates that FCN could effectively hinder the recombination of carriers, and the addition of g-C 3N 4 increases the optical response range of CdS. At the same time, the introduction of Fe 3O 4 magnetic nanoparticles overcomes the problem of difficulty in recovery of the powder photocatalyst. The photocatalytic activity is not reduced to any significant after three cycles of use. 相似文献
16.
A novel molybdenum disulfide (MoS 2) and graphitic carbon nitride (g-C 3N 4) composite photocatalyst was synthesized using a low temperature hydrothermal method. MoS 2 nanoparticles formed on g-C 3N 4 nanosheets greatly enhanced the photocatalytic activity of g-C 3N 4. The photocatalyst was tested for the degradation of methyl orange (MO) under simulated solar light. Composite 3.0 wt.% MoS 2/g-C 3N 4 showed the highest photocatalytic activity for MO decomposition. MoS 2 nanoparticles can increase the interfacial charge transfer and thus prevent the recombination of photo-generated electron–hole pairs. The novel MoS 2/g-C 3N 4 composite is therefore shown as a promising catalyst for photocatalytic degradation of organic pollutants using solar energy. 相似文献
17.
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
18.
The graphitic carbon nitride (g-C 3N 4) was rapidly synthesized via direct high-energy microwave heating approach. During the preparation process, only low-cost melamine and artificial graphite powders were used, without any metal catalysts or inert protective gas. The microstructure was investigated by using X-ray diffraction (XRD), Flourier transformed infrared (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM). The spectra of XRD and HRTEM indicated that the obtained g-C 3N 4 had a high crystallinity. The optical spectra covering Photoluminescence (PL) and Ultraviolet-visible (UV–vis) were also measured at room temperature. PL peak and UV–vis absorption edge of the g-C 3N 4 were shown at 455 nm and 469 nm, respectively, indicating visible-light photocatalytic property. Finally, the photocatalytic activity of g-C 3N 4 was investigated and evaluated as photocatalyst for the photo-degradation of Rhodamine B (RhB) and Methyl Orange (MO) in aqueous solution under visible-light ( λ>420 nm) irradiation, respectively. Results indicated that the g-C 3N 4 sample displayed an excellent performance of removing of RhB and MO due to the improved crystallinity and large surface area of 126 m 2/g. After the visible-light photocatalytic reaction for 40 min, the decolorization ratios of RhB and MO reached up to 100% and 94.2%, respectively. 相似文献
19.
A series of g-C 3N 4–Sb 2S 3/Sb 4O 5Cl 2 (SCL-CX) composite photocatalysts were successfully prepared via a hydrothermal method. The as-prepared materials were characterized by TM3000, powder X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and UV–vis diffuse reflectance spectra (UV–vis DRS). The obtained photocatalyst showed higher photocatalytic activity than pure g-C 3N 4, Sb 4O 5Cl 2 and Sb 2S 3/Sb 4O 5Cl 2 (SCL). The optimum photocatalytic of the composite with the mass of 170 mg g-C 3N 4 and a degradation efficiency up to 95% for methyl orange (MO) under visible light was achieved within 60 min. The enhanced photocatalytic performance could be attributed to the stronger absorption in the visible region and the more efficient electron–hole separation. 相似文献
20.
In this study, we report novel magnetically separable g-C 3N 4/AgBr/Fe 3O 4 nanocomposites as visible-light-driven photocatalysts. The preparation method was simple, large-scale, and low-temperature and did not require any additives or post preparation treatments. The nanocomposites were characterized using X-ray diffraction, transmission electron microscopy, energy dispersive analysis of X-rays, UV–vis diffuse reflectance spectroscopy, Fourier transform-infrared spectroscopy, thermogravimetric analysis, and vibrating sample magnetometry techniques. Photocatalytic activity of the nanocomposites was investigated by degradation of rhodamine B under visible-light irradiation. The nanocomposite with 4:1 weight ratio of g-C 3N 4/AgBr to Fe 3O 4 exhibited superior activity in the degradation reaction. Activity of this nanocomposite was about 5.3 and 5-fold higher than those of g-C 3N 4, and g-C 3N 4/Fe 3O 4, respectively. Moreover, we investigated the influence of refluxing time, calcination temperature, and scavengers of reactive species on the degradation activity. Finally, the photocatalyst was magnetically separated, with high efficiency, from the treated solution after five successive cycles. 相似文献
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