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1.
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
2.
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
3.
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
4.
Although graphitic carbon nitride (g-C 3N 4) has been reported for several decades, it is still an active material at the present time owing to its amazing properties exhibited in many applications, including photocatalysis. With the rapid development of characterization techniques, in-depth exploration has been conducted to reveal and utilize the natural properties of g-C 3N 4 through modifications. Among these, the assembly of g-C 3N 4 with metal oxides is an effective strategy which can not only improve electron–hole separation efficiency by forming a polymer–inorganic heterojunction, but also compensate for the redox capabilities of g-C 3N 4 owing to the varied oxidation states of metal ions, enhancing its photocatalytic performance. Herein, we summarized the research progress on the synthesis of g-C 3N 4 and its coupling with single- or multiple-metal oxides, and its photocatalytic applications in energy production and environmental protection, including the splitting of water to hydrogen, the reduction of CO 2 to valuable fuels, the degradation of organic pollutants and the disinfection of bacteria. At the end, challenges and prospects in the synthesis and photocatalytic application of g-C 3N 4-based composites are proposed and an outlook is given. 相似文献
5.
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
6.
Graphite carbon nitride (g-C 3N 4) is well known as one of the most promising materials for photocatalytic activities, such as CO 2 reduction and water splitting, and environmental remediation through the removal of organic pollutants. On the other hand, carbon nitride also pose outstanding properties and extensive application forecasts in the aspect of field emission properties. In this mini review, the novel structure, synthesis and preparation techniques of full-bodied g-C 3N 4-based composite and films were revealed. This mini review discussed contemporary advancement in the structure, synthesis, and diverse methods used for preparing g-C 3N 4 nanostructured materials. The present study gives an account of full knowledge of the use of the exceptional structural and properties, and the preparation techniques of graphite carbon nitride (g-C 3N 4) and its applications. 相似文献
7.
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
8.
Photocatalysis is one of the most promising ways to realize artificial photosynthesis. The biologically inspired photocatalysts with 3D flower-like structures have attracted much attention. In this study, an effective method for the synthesis of composite photocatalytic material, NH 4TiOF 3/TiO 2/g-C 3N 4, with a 3D camellia-like structure, was developed. The 3D hierarchical structure of the composite material enabled multiple refractions and reflections of light within the catalyst, which greatly improved the efficiency of the sunlight harvesting. The combination of NH 4TiOF 3 and TiO 2 also effectively reduced the electron-hole recombination in the g-C 3N 4. To evaluate its photocatalytic performance, the prepared nanostructured composite materials were tested for the water-splitting with simulated sunlight. It showed the hydrogen evolution at the rate of 3.6 mmol/g/h, which is 4.0 times faster than that from the pure g-C 3N 4. The composite materials exhibited excellent cycling stability. The detailed mechanism of the Z-scheme heterojunction was also discussed. The proposed synthesis route for the creation of 3D flower-like hierarchical composites provides a new effective technique for developing efficient, active, and stable composite photocatalysts for hydrogen production. 相似文献
9.
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
10.
The use of heterojunctions with different semiconductors has shown to be an important strategy to increase the efficiency of heterogeneous photocatalytic processes. In this regard, heterojunctions consisting of ZnO/g-C 3N 4 (x-Zn/gCN) and ZnFe 2O 4/g-C 3N 4 (x-ZF/gCN) were synthesized in different mass proportions of g-C 3N 4 (x = 10, 50 and 80%) through the following simple methods combination: mixture, sonication and thermal treatment. Observations from X-ray diffractometry (XRD), Fourier-transform infrared spectra (FTIR) and field emission scanning electron microscope (FESEM) analyses confirmed that the materials were successfully formed. The g-C 3N 4 incorporation was important in the textural and optical properties modification of the heterojunctions produced. In addition, in the photoluminescence spectroscopy (PL), it was possible to observe g-C 3N 4 influence in the 50-Zn/gCN emission profile changing, reducing the direct recombination rate of the photogenerated charges due to a probable Z-scheme mechanism. This catalyst demonstrated greater efficiency of photocatalytic degradation when compared to the remaining materials, both for cefazolin (CFZ) and reactive black 5 (RB5), reaching 78% and 95%, respectively, after 120 min. Moreover, it also revealed good photostability after five successive cycles. 50-Zn/gCN heterojunction presents a promising character in photocatalytic reactions mediated by solar light for contaminants degradation such as pharmaceutical products and dyes and can be used as an alternative to minimize the effects of water pollution caused during the COVID-19 pandemic. 相似文献
11.
The g-C 3N 4/ZnO nanorods were prepared by simple hydrothermal, grinding and calcination methods. The characterization of g-C 3N 4/ZnO nanorods was done by different analytical techniques such as SEM, TEM, XRD, XPS, FT-IR and UV–Vis. g-C 3N 4/ZnO nanorods with heterostructures have been successfully synthesized without changing the structure between the monomers, which broadens the visible light response range and improves several major pollutants in water degradation rate. Photocatalytic studies were done for the degradation of MB, RhB, Cr(VI) and eosin which are almost fully degraded. The experimental results show that the photocatalytic performance of the nanorods is much better than others. The g-C 3N 4/ZnO photocatalyst has excellent stability and repeated cycle performance. Basing on the results of comprehensive free radical trapping test and ESR tests, it is proposed that the main active substance of the catalyst for degrading dyes is ·0 2-, and ·OH played significant roles in the degradation process. A good photocatalytic mechanism has been proven. 相似文献
12.
Bismuth oxyhalides (BiOX (X = Cl, Br, I) are considered to be an important p-type semiconductors in the photocatalysis applications. In particular, tetragonal BiOBr is considered as a stable photocatalyst due to its resilient absorption in the visible region with an band gap energy of 2.8 eV. In the meantime, lanthanide ions (with 3+ oxidation state) implies as conversion catalyst gained huge impact and remain a serious topic in materials chemistry. Here we synthesized upconversion photocatalyst mainly consists of BiOBr with the Er 3+ and Tb 3+ ions along with low band gap g-C 3N 5 for the improved photocatalytic performances. The synthesized Er 3+/Tb 3+@BiOBr-g-C 3N 5 heterojunction was systematically characterized by XRD, and FT-IR for the confirmation of the composite and their morphology were analysed with FESEM and HR-TEM analysis which revealed that the sheets of g-C 3N 5 were decorated by Er 3+/Tb 3+ loaded BiOBr microspheres. The XPS analysis confirmed the suitable oxidation state of all the individual elements existing in the composite. As the UV-DRS analysis showed that the band gap of the Er 3+/Tb 3+ BiOBr-gC 3N 5 heterojunction was narrowed to 2.64 eV. To evaluate the photocatalytic efficiency of the synthesized g-C 3N 5, Er 3+/Tb 3+@BiOBr and Er 3+/Tb 3+@BiOBr-gC 3N 5 heterojunction under the simulated visible light irradiation source towards the aqueous sulfamethoxazole degradation. The Er 3+/Tb 3+@BiOBr-gC 3N 5 heterojunction shows maximum degradation efficiency of 94.2% after 60 min of visible light irradiation whereas the pure g-C 3N 5 provided about 43.8% and Er 3+/Tb 3+@BiOBr implies 55.2% degradation efficiency. The plausible degradation mechanism of pollutant removal was proposed. 相似文献
13.
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
14.
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
15.
Photocatalytic degradation is an ecologically benign method of reducing organic contaminants in wastewater. To remove the pollutant 1-naphthol, highly efficient 0D/2D Bi 2MoO 6/g-C 3N 4 heterojunctions were successfully assembled by a one-step hydrothermal method, where zero-dimension (0D) Bi 2MoO 6 nanoparticles were firmly bonded to two-dimension (2D) g-C 3N 4 nanosheets. 0D/2D Bi 2MoO 6/g-C 3N 4 exhibited exceptional degradation efficiency for 1-naphthol with a removal rate of 81.5% after 60 min of visible light irradiation. The enhanced photocatalytic ability was attributed to the matched band structures and tightly connected heterojunctions, which effectively prevented the recombination of photogenerated carriers. Besides, the photodegradation mechanism was revealed by investigating the catalysts' crystal phase, morphology, physicochemical and optical properties. This work introduces a novel method for one-step preparation of 0D/2D photocatalysts and advances the utilization of photodegradation for organic pollutants. 相似文献
16.
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
17.
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
18.
The α-Fe2O3/g-C3N4 heterojunction was synthesized using a facile ultrasonic method using alpha hematite (α-Fe2O3) and graphitic carbon nitrite (g-C3N4) as precursors. These samples were characterized by advanced techniques such as SEM, EDX, XRD, PL and UV-Vis to investigate their morphology, elemental composition, crystalline structures and optical properties. Photocatalytic performance of these synthesized materials was investigated via degradation of tetracycline in the aqueous environment upon excitation of visible light. Obtained experimental results indicated that the synthesized α-Fe2O3/g-C3N4 sample exhibited high photocatalytic activity for tetracycline degradation. The improvement in photocatalytic efficiency of the synthesized α-Fe2O3/g-C3N4 was due to the Z-scheme mechanism, which effectively prevented electron-hole recombination or increased electron-hole separation efficiency for photocatalysis. The photocatalytic tetracycline degradation by the α-Fe2O3@g-C3N4 followed the pseudo first-order model. The optimized pH for its photocatalysis was found to be 8. Finally, the synthesized material exhibited high stability after five recycling cycles. 相似文献
19.
In this paper, WO 3 nanorods (NRs)/g-C 3N 4 composite photocatalysts were constructed by assembling WO 3 NRs with sheet-like g-C 3N 4. The as-synthesized photocatalysts were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, UV–vis diffuse reflectance spectroscopy and photoluminescence. The photocatalytic activity of the photocatalysts was evaluated by degradation of Rhodamine B (RhB) under simulated sunlight irradiation. Compared to pristine WO 3 NRs and g-C 3N 4, WO 3 NRs/g-C 3N 4 composites exhibit greatly enhanced photocatalytic activities. The enhanced performance of WO 3 NRs/g-C 3N 4 composite photocatalysts was mainly ascribed to the synergistic effect between WO 3 NRs and g-C 3N 4, which improved the photogenerated carrier separation. A possible degradation mechanism of RhB over the WO 3 NRs/g-C 3N 4 composite photocatalysts was proposed. 相似文献
20.
This paper describes the synthesis of a new series of g-C 3N 4/Nb 2O 5 heterostructures and their application in the removal of organic pollutants from water, as a combined strategy of photocatalysis and adsorption processes. The heterostructures were synthesized at different weight ratios through thermal oxidation and hydrothermal treatment, leading to an uniform assembly of Nb 2O 5 nanoparticles onto g-C 3N 4 surface. The heterostructures exhibited improved textural and electronic properties (narrowing in band gap) when compared to pure g-C 3N 4 and Nb 2O 5, respectively. Although adsorption capacities were shown to be influenced by Nb 2O 5 content, g-C 3N 4 was essential to increase the photocatalytic response of the g-C 3N 4/Nb 2O 5 heterostructures, which displayed an enhancement of photocatalytic performance on the degradation of methylene blue and rhodamine B dyes under visible and ultraviolet irradiation. The enhanced photoactivity was explained by the increase in the lifetime of the charge carries due to formation of heterojunctions between Nb 2O 5 and g-C 3N 4. A mechanistic investigation on the photocatalytic process was conducted by using different reactive scavenger species. The superoxide (O 2−•) radical was found to be the main active specie on the dye photodegradation activated by visible radiation. 相似文献
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