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1.
In this study, a series of novel quaternary g-C3N4/Fe3O4/Ag3PO4/Co3O4 nanocomposites were fabricated. The prepared nanocomposites were characterized by XRD, EDX, SEM, TEM, UV-DRS, FT-IR, PL, TG, and VSM methods to gain insight about structure, purity, morphology, optical, thermal, and magnetic properties. Photocatalytic activity of the samples was investigated under visible-light irradiation by degradations of rhodamine B, methylene blue, methyl orange, and phenol as four organic pollutants. The highest photocatalytic degradation efficiency was observed when the sample calcined at 300 °C for 2 h with 20 wt% of Co3O4. The photocatalytic activity of this nanocomposite is almost 16.8, 15.7, 4.6, and 5.1 times higher than those of the g-C3N4, g-C3N4/Fe3O4, g-C3N4/Fe3O4/Ag3PO4 (20%), and g-C3N4/Fe3O4/Co3O4 (20%) samples in photodegradation of rhodamine B, respectively. Finally, on the basis of the energy band positions, the mechanism of enhanced photocatalytic activity was discussed.  相似文献   

2.
The g-C3N4/Fe3O4/MnWO4 nanocomposites were prepared by a refluxing-calcination procedure. Visible-light-induced photocatalytic experiments showed that the g-C3N4/Fe3O4/MnWO4 (10%) nanocomposite has excellent ability to degrade a range of contaminants including rhodamine B, methylene blue, methyl orange, and fuchsine, which is about 7, 10, 25, and 31 times of the g-C3N4 photocatalyst, respectively. Reactive species trapping experiments revealed that superoxide anion radicals play major role in the photodegradation reaction of rhodamine B (RhB). After the treatment process, the utilized photocatalyst was magnetically recovered and reused with negligible loss in the photocatalytic activity, which is vital in the photocatalytic processes. Finally, a mechanism was proposed for the enhanced interfacial carrier separation and transfer and the improved photocatalytic performance.  相似文献   

3.
The g-C3N4/Fe3O4/Ag/Ag2SO3 nanocomposites have been successfully fabricated by facile refluxing method. The as-obtained products were characterized by XRD, EDX, SEM, TEM, UV–vis DRS, FT–IR, TGA, PL, and VSM techniques. The results suggest that the Ag/Ag2SO3 nanoparticles have anchored on the surface of g-C3N4/Fe3O4 nanocomposite, showing strong absorption in the visible region. The evaluation of photocatalytic activity indicates that for the g-C3N4/Fe3O4/Ag/Ag2SO3 (40%) nanocomposite, the degradation rate constant was 188 × 10?4 min?1 for rhodamine B, exceeding those of the g-C3N4 (16.0 × 10?4 min?1) and g-C3N4/Fe3O4 (20.2 × 10?4 min?1) by factors of 11.7 and 9.3, respectively. The results showed that the nanocomposite prepared by refluxing for 120 min has the superior photocatalytic activity and its activity decreased with rising the calcination temperature. The trapping experiments confirmed that superoxide ion radical was the main active species in the photocatalytic degradation process. Also, it was demonstrated that the magnetic photocatalyst has considerable activity in degradation of one more dye pollutant. Finally, the reusability of the photocatalyst was evaluated by five consecutive catalytic runs. This work may open up new insights into the utilization of magnetically separable nanocomposites and provide new opportunities for facile fabrication of g-C3N4-based plasmonic photocatalysts.  相似文献   

4.
Herein, magnetically recoverable g-C3N4/Fe3O4/Ag2WO4/AgBr (gCN/M/AgW/AgBr) nanocomposites, as greatly efficient visible-light-active photocatalysts, were fabricated by successive decoration of Fe3O4, Ag2WO4, and AgBr over g-C3N4 (gCN) and they were characterized by XRD, EDX, SEM, TEM, HRTEM, UV–vis DRS, FT-IR, PL, TG, and VSM analysis. Visible-light-induced photocatalytic performances were studied by degradations of RhB, MB, MO, and fuchsine pollutants. It was confirmed that the nanocomposites are effective in the reduction of e?/h+ recombination through the matched interactions between energy bands of gCN, Fe3O4, Ag2WO4, and AgBr semiconductors. The highest photocatalytic degradation efficiency was observed for the gCN/M/AgW/AgBr (30%) nanocomposite when it was refluxed for 30?min. Activity of this nanocomposite is almost 21, 41, 94, and 10-folds greater than those of the gCN toward the degradations of RhB, MB, MO, and fuchsine pollutants, respectively. Additionally, a mechanism for the superior photocatalytic performances was proposed using reactive species scavenging experiments and characterization results.  相似文献   

5.
Visible light-responsive SnO2/g-C3N4 nanocomposite photocatalysts were prepared by ultrasonic-assisting deposition method with melamine as a g-C3N4 precursor. The as-prepared photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy, Fourier transform infrared spectra and photoluminescence emission spectra. The photocatalytic activities of the samples were evaluated by monitoring the degradation of methyl orange solution under visible light irradiation (wavelength ≥400 nm). The results show that the SnO2 nanoparticles with the size of 2–3 nm are dispersed on the surface of g-C3N4 evenly in SnO2/g-C3N4 nanocomposites. The visible-light photocatalytic activity of SnO2/g-C3N4 nanocomposites is much higher than that of pure g-C3N4, and increases at first and then decreases with the increment of the content of g-C3N4 in the nanocomposites. The visible-light photocatalytic mechanism of the investigated nanocomposites has been discussed.  相似文献   

6.
《Advanced Powder Technology》2020,31(7):2921-2931
The hybrid graphitic carbon nitride-cadmium oxide (g-C3N4/CdO) nanocomposite was fabricated using chemical precipitation and self-assembly method. The photocatalysts were characterised by XRD, XPS, FTIR, BET, TEM, FESEM, UV-Vis and PL spectroscopy. Based on the optical study, visible light harvesting was improved and the band gap of bulk g-C3N4 to hybrid g-C3N4/CdO nanocomposite was greatly reduced from 2.72 eV to 2.35 eV, signifying a better charge carrier mobility. The photocatalytic activity were further assessed by conducting rhodamine B (RhB) photodegradation reaction using visible light. An excellent dye removal efficiency of 96% was achieved when 1.5 g/L of hybrid g-C3N4/CdO nanocomposite was used with an initial concentration of 10 ppm for 120 min whereas only 66% of RhB was removed by bulk g-C3N4 within the same operating conditions. Besides, reusability tests were carried out and evidenced that hybrid g-C3N4/CdO nanocomposite can be recycled up to four times by retaining the degradation efficiency. The scavenging studies confirmed that the RhB photodegradation using hybrid g-C3N4/CdO nanocomposite was controlled by valance band h+ and O2− oxidation reactions. Conclusively, the inclusion of CdO onto g-C3N4 resulted in remarkable photocatalytic activity for dye degradation applications.  相似文献   

7.
《Materials Research Bulletin》2013,48(4):1447-1452
A facile approach for the preparation of Fe3O4/g-C3N4 nanospheres with good porous structure has been demonstrated by a hydrothermal method. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible light (UV–vis) absorbance spectra and X-ray photoelectron spectroscopy (XPS). The photocatalytic decomposition of methyl orange (MO) by the as-prepared samples was carried out under visible light irradiation. The reusability and magnetic properties were also investigated. The results revealed that the porous Fe3O4/g-C3N4 nanospheres showed considerable photocatalytic activity, and exhibited excellent reusability and magnetic properties with almost no change after five runs.  相似文献   

8.
For the remediation of antibiotic-contaminated water bodies, this study synthesized g-C3N4/CuBi2O4/Bi2MoO6 3D flower-like spherical photocatalysts by a solvothermal method. The tetracycline antibiotics were used as the target pollutants and degraded under visible light to evaluate the photocatalytic performance of the prepared photocatalysts. Notably, the g-C3N4/CuBi2O4/Bi2MoO6 photocatalyst achieved 84.6 % and 91.6 % for the degradation of tetracycline hydrochloride and chlortetracycline (100 mL, 20 mg/L), respectively, within 2 h under visible light irradiation. Furthermore, we found that the composites showed very low degradation rates for dye-based contaminants, but still exhibited excellent photocatalytic activity for antibiotics in a mixed contaminant system of dyes and antibiotics. And the intermediate was detected by gas chromatography-mass spectrometry (GC–MS), suggesting a possible photo-degradation pathway for tetracycline. Finally, biochemical experiments were carried out to further illustrate the effective degradation of antibiotics in water after photocatalytic degradation by observing and comparing the growth of mung bean seeds.  相似文献   

9.
Series of SnO2/g-C3N4 heterojunctions with face-to-face contact have been synthesized by a two-step process. The morphology and photocatalytic property can be adjusted by tailoring the content of g-C3N4 in the heterostructures. The heterojunctions present flower-like morphology and vary the size of flower with the increase of the g-C3N4 content. The 50% SnO2/g-C3N4 heterojunctions exhibit the best performances for photodegradation of rhodamine B under solar light, which is attributed to the effective interfacial contact between SnO2 and g-C3N4, leading to the increased charge transfer and prolonged charge-hole separation time. Moreover, SnO2/g-C3N4 heterojunctions possess excellent stability after 4 recycling runs, because the face-to-face contact interface provides a large contact area, thus forming a close combination of two phases and guaranteeing effective separation of photogenerated carriers. Furthermore, a possible photocatalytic mechanism is analyzed and it is demonstrated that the hydroxyl radical species play an important role for the photocatalytic activity. This research highlights the promising applications of SnO2/g-C3N4 heterojunctions photocatalysts in the field of water purification and environmental remediation.  相似文献   

10.
2D organic g-C3N4 photocatalysts are low cost materials with facile fabrication, suitable bandgap, tunable functionalization, excellent thermal/chemical-physical stability and exceptional photocatalytic behavior, raising considerable interest in photocatalytic and redox research areas. The photocatalytic performance of g-C3N4 mostly relies on the separation/transfer of photo-generated carriers. The mobility properties of the carrier largely determine the formation of reactive species, which have a high impact on surface reactions in the photocatalytic systems based on g-C3N4. This review paper outlines the works carried out so far on the optimization of the carrier mobility dynamics of 2D g-C3N4 materials via the internal and external modification strategies. The peculiar layered planar structure of g-C3N4 allows charge carrier mobility at the interface, in-plane and interlayer, and mechanisms of the charge separation/transfer will also be discussed. Comprehensive conclusions and perspectives on the modification of g-C3N4 leading to satisfactory carrier mobility will be given as well.  相似文献   

11.
In this study, BiVO4/Fe3O4/C60 nanocomposite has been synthesized for the first time using a facile and feasible hydrothermal method. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), vibrating sample magnetometer (VSM), and N2 adsorption-desorption analysis were utilized to analyze the structure, morphology, size, and the magnetic property of the synthesized nanocomposite. The photocatalytic activity of the magnetic BiVO4/Fe3O4/C60 nanocomposite was investigated for the degradation of methylene blue. The results showed that 84% degradation of methylene blue (MB) (25 mg/L) solution within 5 h with a rate constant equal to 0.0049 min?1 in the presence of BiVO4/Fe3O4/C60 nanocomposite and H2O2 (1 mL, 30%) under visible light irradiation. The effects of BiVO4/Fe3O4/C60 dosage, H2O2 amount dye initial concentration and C60 amount on the efficiency of degradation process were investigated. Furthermore, the catalytic activity of the magnetic BiVO4/Fe3O4/C60 nanocomposite was investigated for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) using sodium borohydride (NaBH4) in the aqueous solution and at room temperature. The results showed that BiVO4/Fe3O4/C60 nanocomposite exhibited an excellent performance for the reduction of 4-NP with 97% conversion into its corresponding amino derivative within 38 min with a constant rate equal to 0.0775 min?1. As indicated by the results, the magnetic BiVO4/Fe3O4/C60 nanocomposite exhibited much higher photocatalytic and catalytic activity than BiVO4/ C60, BiVO4/Fe3O4, and pure BiVO4. Moreover, the BiVO4/Fe3O4/C60 nanocomposite could be magnetically separated from the reaction mixture due to the presence of the Fe3O4 and reused without any change in structure.  相似文献   

12.
Lei Ge 《Materials Letters》2011,65(17-18):2652-2654
Novel metal-free g-C3N4 photocatalysts with light yellow colors were synthesized by heating melamine precursor at different temperatures. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectra (DRS). The effect of calcining temperatures on photocatalytic activities of g-C3N4 samples were investigated based on the decomposition of phenol under visible light irradiation. The DRS spectra revealed that the g-C3N4 had strong absorption in the visible light region. The photocatalytic results indicated that the highest phenol degradation of 92.5% was achieved on the samples heated at 520 °C for 4 h. This study may provide an approach to development of novel metal-free photocatalysts to degrade organic pollutants by using visible light.  相似文献   

13.

A highly efficient binary CdIn2S4/g-C3N4 heterojunction photocatalyst was synthesized by a simple wet impregnation method. Photocatalytic system based on the synergistic action of binary CdIn2S4/g-C3N4 heterojunction and H2O2 was proposed to improve the degradation effect of dyes. The photocatalytic activity was evaluated by the degradation of methyl orange(MO) under visible light irradiation. The results demonstrated that contrasted to pure g-C3N4, the synthesized heterojunction can significantly improve the photocatalytic activity. After 120 min of irradiation by visible light, the photocatalytic efficiency of MO degradation of 7CIS/CN was 3.13 times higher than that of g-C3N4. When 60 mM H2O2 was added on this basis, the photocatalytic efficiency increased from 93.81 to 99.40%. The improvement of photocatalytic activity is attributed to the formation of binary CdIn2S4/g-C3N4 heterojunction to promote the transfer of photogenerated electron-hole pairs, and an appropriate amount of H2O2 as an electron trap further reduced the recombination rate of photogenerated electron-hole pairs. Active species capture experiments showed that ·O2? are the main active substances. Subsequently, the mechanism of photocatalytic degradation was proposed. This work provided a new efficient strategy for the degradation of industrial dye wastewater.

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14.
The challenges like the photocatalytic reduction of N2 and elimination of contaminants from the wastewater are accessible by low cost, stable, and visible-light-driven semiconductor-based photocatalysis. A novel g-C3N4/BiSI nanocomposite was synthesized by hydrothermal method and applied for the first time in photocatalytic nitrogen fixation and degradation of methylene blue dye and phenol. The physicochemical features of the photocatalysts were studied by XRD, XPS, FTIR, BET, DRS, FESEM, TEM, EDX mapping, PL, EIS, Mott-Schottky, and photocurrent techniques. Experimental results showed that the production of ammonia in the presence of g-C3N4/BiSI nanocomposite was 1280 μmol L?1 g?1, while this values for g-C3N4 and BiSI were 274 μmol g?1 L?1 and 126 μmol g?1 L?1, respectively. Moreover prepared nanocomposite exhibited a higher rate constant in the MB (537.5 × 10?4 min?1) and phenol (353 × 10?4 min?1) degradation compared with the counterparts. The charge separation efficiency obviously improved, which was ascribed to the charges migration between g-C3N4 and BiSI in an n-n heterojunction system. In addition, high specific surface area and strong visible light absorption were identified as other factors affecting photocatalytic performance. This unique heterojunction photocatalyst has wide application prospects in environmental treatment.  相似文献   

15.
The ternary composites of g-C3N4/N-TiO2/FACs (FAC: Fly Ash Cenospheres) were synthesized by an in-situ hydrolysis method to improve the photocatalytic activity and their stability. When TiO2 was anchored on FAC, it was easily to be separated from the aqueous solution and could be repeatedly utilized. In the present experiments, the degradation rate remained for more than 68% even after the composite reused for seven times. The band gap of g-C3N4/N-TiO2/FAC was 2.75?eV, which might be owing to the synergistic effect between N-TiO2 and g-C3N4. The composite of g-C3N4/N-TiO2/FAC had an ideal activity of 72.2% under visible light illumination for 180?min. It was about 1.3 times of N-TiO2/FAC and 3.5 times of g-C3N4. The synergistic effect of SiO2, Fe2O3 and TiO2 components resulted to the improvement of photocatalytic performance.  相似文献   

16.
The development of high-efficiency photocatalysts is an attractive strategy for pollutants degradation under visible light. Herein, novel photocatalysts are reported through coupling Sb2MoO6 with g-C3N4 nanotube (abbreviated as GCN nanotube) by a simple reflux method. Also, the nanocomposites were defined by applying various analyses. Under visible-light excitation, the GCN nanotube/Sb2MoO6 systems had more photoactivity than g-C3N4 (abbreviated as GCN) and the rate constant for RhB removal on optimal GCN nanotube/Sb2MoO6 (30%) nanocomposite was 48.3 times premier than the GCN. Also, compared to the pristine GCN, the GCN nanotube/Sb2MoO6 (30%) sample demonstrated supreme photoactivity towards tetracycline degradation and Cr (VI) photoreduction, which was 88.5 and 21.8 times higher than the bulk GCN, respectively. These impressive enhancements were attributed to the quick segregation of charge carriers, boosted visible-light absorption, and extended specific surface area. Moreover, the photocatalyst has enough activity after four successive cycles. Finally, a conceivable charges transfer route is presented through n-n heterojunction constructed between Sb2MoO6 and GCN nanotube.  相似文献   

17.

In this research, zero-dimensional (quantum dots) of graphitic carbon nitride (g-C3N4) and Fe3O4 nanoparticles were decorated on MoS2 nanosheets to prepare MoS2/Fe3O4/g-C3N4 quantum dots. Photocatalytic activities of newly synthesized nanocatalyst were investigated by the degradation of methylene blue (MB) and methyl orange (MO) under visible LED lamp light. In these degradation reactions, the parameters effective such as dyes concentration, pH, amount of catalyst, and irradiation time were also investigated. The systematic investigations revealed that 10 mg of MoS2/Fe3O4/g-C3N4QDs catalyst was optimum to degrade 10 mg/L of MB and 40 mg of nanocatalyst to degrade 10 mg/L of MO with 60 W of LED irradiation. Nanocomposite can act as an excellent photocatalyst for degradation of MB and MO at short time intervals and also can be easily separated by an external magnet and reused several times. The kinetic data acquired for the degradation of dyes were matched to first-order rate equations, and also the apparent rate constants for the degradation of MB and MO were calculated as follows: K?=?0.285 min?1 and K?=?0.263 min?1, respectively. The novelty of catalyst is due to metal (Mo) and non-metal (S) in the structure of substrate (MoS2), so Fe3O4 and g-C3N4 QDs can be strongly connected to the substrate. The structure and morphology of prepared nanocomposite were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), scanning electron microscopy (SEM) energy dispersive X-ray spectroscopy (EDS), and UV–Vis spectroscopy.

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18.
Emerging artificial photosynthesis promises to offer a competitive means for solar energy conversion and further solves the energy crisis facing the world. Hydrogen peroxide (H2O2), which is considered as a benign oxidant and a prospective liquid fuel, has received worldwide attention in the field of artificial photosynthesis on account of the source materials are just oxygen, water, and sunlight. Graphitic carbon nitride (g-C3N4)-based photocatalysts for H2O2 generation have attracted extensive research interest due to the intrinsic properties of g-C3N4. In this review, research processes for H2O2 generation on the basis of g-C3N4, including development, fabrication, merits, and disadvantages, and the state-of-the-art methods to enhance the performance are summarized after a brief introduction and the mechanism analysis of an efficient catalytic system. Also, recent applications of g-C3N4-based photocatalysts for H2O2 production are reviewed, and the significance of active sites and synthetic pathways are highlighted from the view of reducing barriers. Finally, this paper ends with some concluding remarks to reveal the issues and opportunities of g-C3N4-based photocatalysts for producing H2O2 in a high yield.  相似文献   

19.
通过简单的水热法制备了Co3O4/rGO/g-C3N4催化剂,并在可见光照射下用于光催化臭氧氧化降解2,4-二氯苯氧乙酸(2,4-D)。利用XRD, SEM, TEM, XPS, UV-vis DRS, FT-IR和瞬态光电流对样品进行测试表征。研究表明,Co3O4, rGO和g-C3N4形成异质结后光生电子-空穴(e--h+)对的分离效率,e-的迁移能力以及光催化臭氧氧化活性都明显提升。此外,0.5Co3O4/0.25rGO/GCN对2,4-D具有100%的去除率,并具有最高反应速率(k=0.070 9 min-1)。经过计算得出光催化臭氧氧化2,4-D的协同因子为3.91,表明光催化和臭氧氧化间具有较好的协同效应。活性组分的捕获实验结果表明h+和·OH是光催...  相似文献   

20.
This work was designed to synthesize SrMoO4/g-C3N4 heterojunction for efficient degradation of tetracycline (TC) hydrochloride via photocatalysis. SrMoO4/g-C3N4 samples were prepared through a grinding and roasting process. The prepared nanocomposite exhibited excellent visible-light-driven photocatalytic activity. The reaction rate of TC photodegradation reaches 0.0171 min?1, which is 5.9 times higher than that of neat g-C3N4. The origin of the high photoactivity of SrMoO4/g-C3N4 was investigated using a variety of characterization techniques including XRD, FT-IR, TG, SEM, TEM, XPS, DRS, Mott-Schottky, PL, PC, and EIS. Result showed that the added SrMoO4 was closely loaded on the g-C3N4 surface, which is conducive to the electron transfer between SrMoO4 and g-C3N4. Mott-Schottky analysis indicated that SrMoO4 has a lower conduction band (CB) position than g-C3N4. As a result, photogenerated electrons in g-C3N4 can move to the CB of SrMoO4 to hinder the recombination of charge carriers, thereby increasing the photocatalytic activity under visible light. The cycling test further suggested that the SrMoO4/g-C3N4 heterojunction has good stability in the photocatalytic degradation of TC. Super oxygen radicals and holes are the main reactive species.  相似文献   

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