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1.
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
2.
A series of g-C 3N 4/ZnAl 2O 4 composites were prepared using a conventional calcination method and the heterostructures were systematically characterized. It was found that the combination of g-C 3N 4 with ZnAl 2O 4 significantly improve their photocatalytic activities. The optimum photocatalyst of composite is at 5% (wt%) of ZnAl 2O 4, whose degradation efficiency for methyl orange (MO) was 96% within 120 min under visible-light irradiation. The formation of heterojunction between g-C 3N 4 and ZnAl 2O 4 can facilitate efficient charge separation of photogenerated electron-hole pairs, which were confirmed by electrochemical impedance spectroscopy (EIS). As a result, the photocatalytic properties of composites were enhanced. 相似文献
3.
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
4.
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
5.
BiPO 4/g-C 3N 4 with different amounts of BiPO 4 was prepared through wet impregnation with calcination method. The BiPO 4/g-C 3N 4 showed large surface area (172.9 m 2 g − 1) and the incorporation of BiPO 4 caused a red-shift of g-C 3N 4 in visible light. The photocatalytic degradation of toluene over the samples was investigated. The degradation of toluene could get 82% in BiPO 4/g-C 3N 4 photocatalysts under optimum reaction conditions. The BiPO 4/g-C 3N 4 exhibited a higher photocatalytic activity than pure g-C 3N 4 or BiPO 4. The improved photoactivity of BiPO 4/g-C 3N 4 could be attributed to strong absorption in visible light and effective separation of photo-induced hole-electron pairs between BiPO 4 and g-C 3N 4. 相似文献
6.
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
7.
A novel TiO 2 − xN x/BN composite photocatalyst was prepared via a facile method using melamine–boron acid adducts (M·2B) and tetrabutyl titanate as reactants. The morphological results confirmed that nitrogen-doped TiO 2 nanoparticles were uniformly coated on the surface of porous BN fibers. A red shift of absorption edge from 400 nm (pure TiO 2) to 520 nm (TiO 2 − xN x/BN composites) was observed in their UV–Vis light absorption spectra. The TiO 2 − xN x/BN photocatalysts exhibited enhanced photocatalytic activity for the degradation of Rhodamine B (RhB) and the highest photocatalytic degradation efficiency reached 97.8% under visible light irradiation for 40 min. The mechanism of enhanced photocatalytic activity was finally proposed. 相似文献
8.
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
9.
A series of onion-like carbon modified porous g-C 3N 4 (OLC/pg-C 3N 4) composites have been fabricated by a simple ultrasonic adsorption approach. The resultant OLC/pg-C 3N 4 composites exhibit excellent photocatalytic activity and stability towards the degradation of the dyes and phenol in aqueous solution under visible-light irradiation. The composite with 2.0 wt% OLC content shows the optimal photocatalytic activity for degrading rhodamine B (RhB), its rate constant is about three times that of pure pg-C 3N 4. The improved photocatalytic activity is mainly attributed to the synergetic effect of pg-C 3N 4 and OLC, including larger surface area, stronger visible light adsorption and efficient separation of photogenerated electrons and holes. Moreover, a possible mechanism of photocatalytic reaction over OLC/pg-C 3N 4 composite is proposed. 相似文献
10.
Tin dioxide nanoparticles were prepared in the presence of graphitized carbon nitride (g-C 3N 4) forming nanocomposites with different contents of SnO 2 up to 40 %. G-C 3N 4 was synthetized by heating of melamine at 550 °C in the open air and Sn 2+ ions were precipitated by sodium hydroxide in g-C 3N 4 aqueous dispersions. Resulting mixtures were dried by freezing at ?20 °C and calcined at 450 °C to obtain SnO 2/g-C 3N 4 nanocomposites.The nanocomposites were characterized by common characterization methods in solid state and in their aqueous dispersions using dynamic light scattering (DLS) analysis and photocatalysis. SnO 2 nanoparticles in the nanocomposites were found to have an average size of 4 nm, however, those precipitated without g-C 3N 4 had an average size of 14 nm. Separation of photoinduced electron and holes via heterojunction between SnO 2 and g-C 3N 4 was demonstrated by photocatalytic decomposition of Rhodamine B (RhB) under LED visible irradiation (416 nm) and photocurrent measurements. The most photocatalytically active nanocomposite contained 10 % of SnO 2. Graphitized carbon nitride was assumed to serve as a template structure for the preparation of SnO 2 nanoparticles with a narrow size distribution without using any stabilizing additives. 相似文献
11.
Molybdenum doped graphitic carbon nitride (g-C 3N 4) catalysts were prepared by a simple pyrolysis method using melamine and ammonium molybdate as precursors. The characterization results indicated that the obtained Mo-doped g-C 3N 4 catalysts had worm-like mesostructures with higher surface area. Introduction of Mo species can effectively extend the spectral response property and reduce the recombination rate of photogenerated electrons and holes. CO 2 photocatalytic reduction tests showed that the Mo-doped g-C 3N 4 catalysts exhibited considerably higher activity (the highest CO and CH 4 yields of 887 and 123 μmol g − 1-cat., respectively, after 8 h of UV irradiation.) compared with pure g-C 3N 4 from melamine. 相似文献
12.
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
13.
g-C 3N 4 as a new metal-free photocatalytic material for water splitting has attracted much attention in recent years, but its photocatalytic efficiency needs further improvement. Here we synthesized novel C 60/graphene/g-C 3N 4 composite photocatalytic materials with high hydrogen generation ability for water splitting under visible light radiation (λ>420 nm). These materials take full advantage of the electron conduction expressing of graphene and the superior-strong electron-attracting ability of C 60. The mutually-reinforcing synergy between graphene and C 60 improves the migration and utilization efficiency of photo-generated electrons and accelerates the separation of photo-generated charges, thus significantly enhancing the hydrogen generation capacity of g-C 3N 4. The hydrogen production amount and rate of C 60/graphene/g -C 3N 4 (10 mg/L C 60 and graphene) after 10 h are 5449.5 µmol/g and 545 µmol/g/h, which is 539.6 times of pure g-C 3N 4 under the same condition. The values are 50.8 and 4.24 times of graphene/g-C 3N 4 (10 mg/L graphene) and C 60/g-C 3N 4 (10 mg/L C 60), respectively. The apparent quantum yield of C 60/graphene/g -C 3N 4 (10 mg/L C 60 and graphene) in 97 h is about 7.2%. The improvement of hydrogen generation activity in 97 h suggests the high long-time stability of C 60/graphene/g -C 3N 4 in photocatalytic water spitting. The photocatalytic ability of C 60/graphene/g -C 3N 4 can be controlled by regulating the addition of graphene and C 60. The mutually-reinforcing synergy between graphene and C 60 was proved by X-ray photoelectron spectroscopy, photoluminescence spectrum and organic electron acceptors of MV 2+. Thus, the joint action of C 60 and graphene promotes the migration, separation and utilization of photo-generated electrons, which is responsible for the significant enhancement of photocatalytic performance. 相似文献
14.
The solar light sensitive g-C 3N 4/TiO 2 heterojunction photocatalysts containing 20, 50, 80, and 90 wt% graphitic carbon nitride (g-C 3N 4) were prepared by growing Titania (TiO 2) nanoparticles on the surfaces of g-C 3N 4 particles via one step hydrothermal process. The hydrothermal reactions were allowed to take place at 110 °C at autogenous pressure for 1 h. Raman spectroscopy analyses confirmed that an interface developed between the surfaces of TiO 2 and g-C 3N 4 nanoparticles. The photocatalyst containing 80 wt% g-C 3N 4 was subsequently heat treated 1 h at temperatures between 350 and 500 °C to improve the photocatalytic efficiency. Structural and optical properties of the prepared g-C 3N 4/TiO 2 heterojunction nanocomposites were compared with those of the pristine TiO 2 and pristine g-C 3N 4 powders. Photocatalytic activity of all the nanocomposites and the pristine TiO 2 and g-C 3N 4 powders were assessed by the Methylene Blue (MB) degradation test under solar light illumination. g-C 3N 4/TiO 2 heterojunction photocatalysts exhibited better photocatalytic activity for the degradation of MB than both pristine TiO 2 and g-C 3N 4. The photocatalytic efficiency of the g-C 3N 4/TiO 2 heterojunction photocatalyst heat treated at 400 °C for 1 h is 1.45 times better than that of the pristine TiO 2 powder, 2.20 times better than that of the pristine g-C 3N 4 powder, and 1.24 times better than that of the commercially available TiO 2 powder (Degussa P25). The improvement in photocatalytic efficiency was related to i) the generation of reactive oxidation species induced by photogenerated electrons, ii) the reduced recombination rate for electron-hole pairs, and iii) large specific surface area. 相似文献
15.
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
16.
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
17.
Porous peanut-like BiVO 4 and BiVO 4/Fe 3O 4 submicron structures were synthesized by a template-free hydrothermal process at 160 °C for 24 h. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM) and UV –vis spectroscopy. The photocatalytic activity of BiVO 4 and BiVO 4/Fe 3O 4 submicron structures were evaluated for the degradation of Rhodamine B (RhB) and methylene blue (MB) under visible light irradiation with and without the assistance of H 2O 2. According to the experimental results obtained, porous peanut-like BiVO 4/Fe 3O 4 composite photocatalyst shows higher photocatalytic activity in the H 2O 2-assisted system under visible light irradiation compared to BiVO 4. Recycling test on the BiVO 4/Fe 3O 4 composite photocatalyst for the degradation of RhB under visible light irradiation indicates that the composite photocatalyst is stable in the H 2O 2-assisted system in five cycles. Therefore, this composite photocatalyst will be beneficial for efficient degradation of organic pollutants present in water and air under solar light. 相似文献
18.
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
19.
TiO 2/MoS 2 composite was encapsulated by hydrophobic SiO 2 nanoparticles using a sol–gel hydrothermal method with methyltriethoxysilane (MTES), titanium tetrachloride (TiCl 4), and molybdenum disulfide (MoS 2) as raw materials. Then, a novel dual functional composite film with hydrophobicity and photocatalytic activity was fabricated on a glass substrates via the combination of polydimethylsiloxane adhesives and hydrophobic SiO 2@(TiO 2/MoS 2) composite particles. The influence of the mole ratios of MTES to TiO 2/MoS 2 (M:T) on the wettability and photocatalytic activity of the composite film was discussed. The surface morphology, chemical compositions, and hydrophobicity of the composite film on the glass substrate were investigated by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and water contact angle (water CA) measurements. The results indicated that the composite film exhibited stable superhydrophobicity and excellent photocatalytic activity for degradation of methyl orange (MO) even after five continuous cycles of photocatalytic reaction when M/T was 7:1. The water CA and degradation efficiency for MO remained at 154° and 94%, respectively. Further, the composite film showed a good non-sticking characteristic with the water sliding angle (SA) at about 4°. The SiO 2@(TiO 2/MoS 2) composite consisting of hydrophobic SiO 2 nanoparticles and TiO 2/MoS 2 heterostructure could provide synergistic effects for maintaining long-term self-cleaning performance. 相似文献
20.
This work presents a novel composite photocatalyst, AgCl/Bi 3O 4Cl, which was prepared using an ion-exchange method. The synthesized composite was characterized by various techniques and its photocatalytic activity was investigated in RhB degradation under visible light irradiation. Results indicated that the introduction of AgCl into Bi 3O 4Cl promoted the specific surface area, light absorption performance and the separation efficiency of electron–hole pairs, which resulted in a high photocatalytic activity of the composite. The optimal AgCl/Bi 3O 4Cl sample showed a RhB degradation rate of 0.048 min − 1, which was 2.2 and 2.4 times higher than those of AgCl and Bi 3O 4Cl, respectively. 相似文献
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