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1.
In this contribution, a Z-scheme mesoporous BiVO 4/g-C 3N 4 nanocomposite heterojunction with a considerable surface area and high crystallinity was synthesized by a simple soft and hard template-assisted approach. This material demonstrates superior visible light-driven photocatalysis for the photoreduction of Hg(II) ions. TEM and XRD results show that the mesoporous BiVO 4 NPs, with a monoclinic phase and an ellipsoid-like shape, are highly dispersed onto the porous 2D surfaces of g-C 3N 4 nanosheets with a particle size of 5–10 nm. The obtained BiVO 4/g-C 3N 4 nanocomposites with a p-n heterojunction show significantly enhanced Hg(II) photoreduction efficiency compared to the mesoporous BiVO 4 NPs and pristine g-C 3N 4. Among all synthesized photocatalysts, the 1.2% BiVO 4/g-C 3N 4 nanocomposite indicated the highest photoreduction of Hg(II) performance, reaching ~ 100% within 60 min; this result is 3.9 and 4.5 –fold larger than that of the BiVO 4 NPs and pristine g-C 3N 4. The Hg(II) photoreduction rates highly increase to 208.90, 314.95, 411.23 and 418.68 μmol g −1min −1 for the mesoporous 0.4, 0.8, 1.2 and 1.6% BiVO 4/g-C 3N 4 nanocomposites, respectively. The reduction rate of the mesoporous 1.2% BiVO 4/g-C 3N 4 nanocomposite demonstrated a 5.2 and 3.8 times larger increase than that of the pristine g-C 3N 4 nanosheets and pure BiVO 4 NPs. The superior Hg(II) photoreduction efficiency was ascribed to decreased carrier recombination and the improved utilization of visible light by constructing BiVO 4/g-C 3N 4 nanocomposites with a p-n junction. Transient photocurrent measurement and photoluminescence spectra were employed to confirm the possible Hg(II) photoreduction mechanism over these BiVO 4/g-C 3N 4 photocatalysts. This research provides an accessible route for the nanoengineered design of mesoporous BiVO 4/g-C 3N 4 heterostructures that demonstrated unique photocatalytic performance. 相似文献
2.
Excellent charge carrier kinetics and high light absorption capability are key factors in increasing photocatalytic efficiency. Here, novel mesoporous CoTiO 3/g-C 3N 4 heterostructures at varying CoTiO 3 percentages were synthesized utilizing an easy soft and hard template approach for the degradation of acridine orange (AO) under visible light exposure. The TEM images exhibited irregular nanocrystals containing stacked g-C 3N 4 layers with crimped nanosheets, and spherical CoTiO 3 NPs (10 nm) were uniformly distributed throughout the g-C 3N 4 layers. The results indicated that the mesoporous 3%CoTiO 3/g-C 3N 4 heterostructure exhibited the highest degradation of AO dye (100%) within 60 min compared to g-C3N4 (10%) and CoTiO3 (18%). Furthermore, the 3% CoTiO 3/g-C 3N 4 heterostructure had a better degradation rate, approximately 10.75- and 6.93-fold larger than those of g-C 3N 4 and CoTiO 3 NPs, respectively. The enhanced mesoporous CoTiO 3/g-C 3N 4 exhibited effective photoinduced carrier separation, a widened light harvesting range, and synergistic effects. Additionally, the 3% CoTiO 3/g-C 3N 4 heterostructure revealed superior photocatalytic stability in AO dye recycling degradation for long-life regeneration. A direct Z-scheme mechanism was suggested for the degradation of AO dye over mesoporous CoTiO 3/g-C 3N 4, and it was further supported by photoluminescence (PL) spectroscopy and photoelectrochemical responses. The present work demonstrates new insight and an approach to synthesizing mesoporous CoTiO 3/g-C 3N 4 heterostructures for various potential applications. 相似文献
3.
In this study, mesoporous Bi 2WO 6/g-C 3N 4 heterojunctions were developed using soft and hard templates [triblock copolymer surfactant (F127) and mesoporous silica (MCM-41), respectively]. The performance of the developed heterojunctions was assessed through the photocatalytic reduction of mercuric cations under Vis light illumination, with HCOOH being adopted to provide sacrificial holes agent. Surface measurements demonstrated that the fabricated specimens acquired large specific surface areas when compared with the neat ingredient. Furthermore, a transmission electron microscopy (TEM) analysis of the developed heterojunctions showed the homogeneous distribution of the spherical Bi 2WO 6 nanoparticles (NPs) on the surface of g-C 3N 4 nanosheets. Meanwhile, an accelerated rate (700 μ·mol·g ?1·h ?1) of photocatalytic mercuric cation reduction with improved efficiency (approximately 100%), compared with those of the pure ingredients [rate of 55 μ·mol·g ?1·h ?1 and efficiency of 13% for g-C 3N 4 nanosheets; rate of 95 μ·mol·g ?1·h ?1 and efficiency of 20% for mesoporous Bi 2WO 6 NPs], was accomplished via testing of the Bi 2WO 6/g-C 3N 4 heterojunction comprising 4 wt% Bi 2WO 6 after 40 min of illumination. Evidently, the efficiency of the photocatalytic reduction of mercuric cations endorsing the Bi 2WO 6/g-C 3N 4 heterojunction comprising 4 wt% Bi 2WO 6 NPs is 7.7 and 5 times more when compared with those of the neat g-C 3N 4 nanosheets and mesoporous Bi 2WO 6 NPs, respectively. The improved performance of the fabricated heterojunctions in the photocatalytic reduction of mercuric cations could be ascribed to i) fast diffusion of the mercuric cations through the mesoporous texture to the active ensembles, ii) greater specific surface area, iii) limited bandgap magnitude, iv) homogenous dispersion of the Bi 2WO 6 NPs on the surface of the nanosheets, and v) finite particle dimension of the mesoporous Bi 2WO 6 NPs. The durability and stability of the Bi 2WO 6/g-C 3N 4 heterojunctions were confirmed via their recyclability, which was maintained for up to five runs without pronounced activity loss. 相似文献
4.
Herein, novel mesoporous CdS nanoparticle (NP)-incorporated porous g-C 3N 4 nanosheets with large surface areas and varying CdS NP percentages were constructed for the first time. The synergistic effect of mesoporous CdS NPs and porous g-C 3N 4 nanosheets indicated effective charge carrier separation and promoted CO 2 photoreduction to form CH 3OH upon illumination. The highest yield of CH 3OH over 3% CdS-g-C 3N 4 heterostructures was determined to be approximately 1735 μmol g ?1, which was 3.8- and 5.50 times greater than those of mesoporous CdS NPs and pristine g-C 3N 4 nanosheets, respectively. In addition, the mesoporous 3%CdS-g-C 3N 4 heterostructure showed an outstandingly enhanced CO 2 photoreduction rate of 192.7 μmol g ?1 h ?1, which was estimated to be ~4.1 and 5.9- times better than CdS (47.1 μmol g ?1 h ?1) and pristine g-C 3N 4 (32.6 μmol g ?1 h ?1), respectively. The photoreduction performance was retained at approximately 94.7% after five cycles of illumination for 45 h. The remarkable synthesized mesoporous CdS-g-C 3N 4 heterostructure played an essential role, with its narrow bandgap and high surface area enabling improved photoinduced carrier separation and a widened range of light absorption. A plausible mechanism for CO 2 photoreduction by the mesoporous CdS-g-C 3N 4 heterostructure was proposed and verified by photoelectrochemical and photoluminescence measurements. 相似文献
5.
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
6.
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
7.
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
8.
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
9.
A novel Ag 4V 2O 7/g-C 3N 4 heterostructure was synthesized by a facial etching method in ammonia solution using Ag 2VO 2PO 4/g-C 3N 4 as a self-sacrifice precursor. With the concentration of ammonia solution increasing from 0.05 to 0.2 M, phase transformation took place, described as: Ag 2VO 2PO 4/g-C 3N 4 → Ag 2VO 2PO 4/Ag 4V 2O 7/g-C 3N 4 → Ag 4V 2O 7/g-C 3N 4. Compared with pristine Ag 2VO 2PO 4/g-C 3N 4, the etched samples of Ag 4V 2O 7/g-C 3N 4 and Ag 2VO 2PO 4/Ag 4V 2O 7/g-C 3N 4 exhibited dramatically improved activity for the degradation of methylene blue (MB), methyl orange (MO) and imidacloprid under visible light irradiation. When etched with 0.15 M ammonia solution, an Ag 4V 2O 7/g-C 3N 4 heterostructure was obtained that exhibited the highest photoactivity. This photocatalyst was nearly 9.1, 3.0, and 24.3 times more efficient than pristine Ag 2VO 2PO 4/g-C 3N 4 for degradation of MB, MO and imidacloprid, respectively. The excellent photocatalytic performance can be ascribed to the as-obtained well-defined Ag 4V 2O 7/g-C 3N 4 heterojunction, which improves the separation and transfer efficiency and prolongs the lifetime of photoinduced charges. In addition, the stability and dominant radicals were investigated. 相似文献
10.
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
11.
The production of fuels with a low sulfur content has been paid significant attention in the manufacturing of petroleum refining due to the progressively severe environmental legislations obliged by governments worldwide. In this paper, for the first time, two dimensional mesoporous Ag 2O/ZrO 2 heterostructures were synthesized by a facile approach for thiophene photocatalytic oxidative desulfurization under visible-light exposure at room temperature. The Ag 2O/ZrO 2 heterostructures significantly enhanced the photocatalytic desulfurization of thiophene obeyed the pseudo-first-order model compared to pristine ZrO 2 NPs. In particular, 1.5%Ag 2O/ZrO 2 photocatalyst exhibited better photocatalytic performance and the correspondent rate constant of 0.0235 min ?1, which was promoted 5.35 times than that of pristine ZrO 2 NPs (0.0044 min ?1). The desulfurization rate of thiophene over 1.5% Ag 2O/ZrO 2 heterostructure was enhanced 3.7 times larger than that of pristine ZrO 2 NPs. The thiophene was photocatalytically oxidized to CO 2 and SO 3. The photocatalytic performance of Ag 2O/ZrO 2 could be enhanced because of its synergetic effects, the intense visible-light harvest, rapid mobility of the thiophene to the active sites, a lower light scattering effect, and a large ?OH radical contents formed. Moreover, the Ag 2O/ZrO 2 heterostructures revealed excellent stability toward the photocatalytic oxidative desulfurization of thiophene. A possible charge separation mechanism over mesoporous Ag 2O/ZrO 2 heterostructures was proposed. 相似文献
12.
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
13.
Mesoporous single-crystalline perovskite YFeO3 nanoparticles was synthesized through a soft template-assisted approach. Mesoporous YFeO3 NPs were decorated porous g-C3N4 nanosheets with variation YFeO3 NPs percentages, and the newly synthesized photocatalysts were assessed towards Hg(II) reduction and HCOOH oxidation in aqueous solution upon visible light exposure. XRD and HR-TEM revealed the formation of single-crystalline orthorhombic YFeO3 with uniformly dispersed and the average particle size of 10?±?5 nm, thereby constructing a mesoporous YFeO3/g-C3N4 heterojunctions for the promotion of the photocatalytic performances compared to bare YFeO3 NPs and g-C3N4. 3% YFeO3/g-C3N4 heterostructure revealed the highest and optimum Hg(II) reduction (100%) within 60 min, which determined 3.7 and 5 times larger than of bare YFeO3 NPs and g-C3N4 obeyed by pseudo-first-order kinetics. The YFeO3/g-C3N4 photocatalyst could be recycled five continuous cycles and kept remarkable photostability for long time illumination. The superior Hg(II) reduction over mesoporous YFeO3/g-C3N4 heterojunction is referred to as lower recombination of carriers, the unique electronic structure, higher visible light utilization and high surface area. This work focused on constructing the YFeO3/g-C3N4 heterojunction, indicating outstanding photocatalytic performances in a facile route. 相似文献
14.
The construction of photocatalyst with gradient band structure is guided by the principle of band gap engineering. Rational structural design is advanced and applied to construct a new-typed peculiarly structural and functional carbon-based [TiO 2/C]//[Bi 2WO 6/C] Janus nanofiber modified by g-C 3N 4 nanosheets heterostructure photocatalyst (denoted as TB-JgHP). The flexible carbon-based [TiO 2/C]//[Bi 2WO 6/C] Janus nanofiber with one side responding to ultraviolet light and the other capturing visible light is fabricated by conjugate electrospinning, and then g-C 3N 4 nanosheets are uniformly grown in-situ on the surface of the Janus nanofibers by using gas-solid reaction via gasification of urea. The optimized TB-JgHP possesses remarkable hydrogen evolution efficiency (17.48 mmol h −1 g −1) and methylene blue degradation rate (99.2%) under simulated sunlight illumination for 100 min, demonstrating prominent dual-functional characteristics. The enhanced photocatalytic performance benefits from the unique Janus structure as well as the synergistic effects among the triple heterostructures of TiO 2 and Bi 2WO 6, g-C 3N 4 and TiO 2, g-C 3N 4 and Bi 2WO 6. The formation of gradient band structure among heterostructures is more conducive to the multi-step separation of photo-induced electron-hole pairs and more effective absorption of light. Further, flexible self-standing carbon-based photocatalysts not only have outstanding electron transport performance, but also are easy to separate from solution with preeminent recyclable stability. Based on a series of characterization techniques, it is further proved that TB-JgHP has higher carrier separation efficiency than the counterpart contrast samples. The formation mechanism of TB-JgHP is proposed, and the construction technique is established. The design philosophy and construction technique presented in this work pave a new avenue for research and development of other heterostructure photocatalysts. 相似文献
15.
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
16.
Mesoporous g-C 3N 4 nanosheets (MCN) with uniform pore size were utilized to decorate mesoporous TiO 2 spheres (TSs) to form a core-shell heterojunction photocatalyst containing uniform mesopores. Moreover, the mesoporous g-C 3N 4 nanosheets served as shells for composites, in addition to playing a pivotal function for the regulation of the pore structure of the composite. The mesoporous TiO 2@g-C 3N 4 core/shell structure having a uniform pore size exhibited high surface area of ∼134 m 2/g. This coupled material with improved porosity, not only led to increased visible-light absorption but also led to the enhanced charge generation/separation. In addition, it showed a lengthy cycling stability with highly active visible-light efficiency to degrade Rhodamine B (RhB) dye. 相似文献
17.
Heterojunction engineering is considered as a hopeful approach to ameliorate the separation of photogenerated carriers of photocatalysts, realizing efficient water-splitting performance. In this study, an organic-inorganic S-scheme of a one-dimensional g-C 3N 4 nanotube (TCN)/Ag 3PO 4 photocatalytic system with high photocatalytic water oxidation activity was designed by coupling g-C 3N 4 nanotubes over Ag 3PO 4 particles through a chemical coprecipitation method. The TCN/Ag 3PO 4 heterojunction demonstrated excellent photocatalytic O 2 production with an O 2 evolution rate of up to 370.2 μmol·L ?1·h ?1. X-ray photoelectron spectroscopy analysis showed that electron migration between TCN and Ag 3PO 4 led to the formation of an internal electric field pointing from TCN to Ag 3PO 4, which drove the S-scheme charge transfer mode between TCN and Ag 3PO 4. Accordingly, the TCN/Ag 3PO 4 heterojunction possessed fast charge separation and high redox ability, leading to high photoactivity and photostability. This research provides a new strategy for fabricating highly efficient inorganic-organic S-scheme photocatalysts for O 2 production. 相似文献
18.
Microcystins (MCs) is a harmful toxin generated by blue-green algae in water, which has seriously threatened the ecological safety of water and human body. It is urgent to develop new catalysts and techniques for the degradation of MCs. A feasible electrostatic self-assembly method was carried out to synthesize BiVO 4/g-C 3N 4 heterojunction photocatalyst with highly efficient photocatalytic ability, where BiVO 4 nanoplates with exposed {010} facets anchored to the g-C 3N 4 ultrathin nanosheets. The morphology and microstructure of the heterojunction photocatalysts were identified by XRD, SEM, TEM, XPS, and BET. The g-C 3N 4 nanosheets have huge surface area over 200 m 2/g and abundant mesoporous ranging from 2-20 nm, which provides tremendous contact area for BiVO 4 nanoplates. Meanwhile, the introduction of BiVO 4 led to red-shift of the absorption spectrum of photocatalyst, which was characterized by UV-vis diffuse reflection spectroscopy (DRS). Compared with pure BiVO 4 and g-C 3N 4, the BiVO 4/g-C 3N 4 heterojunction shows a drastically enhanced photocatalytic activity in degradation of microcystin-LR (MC-LR) in water. The MC-LR could be removed within 15 minutes under the optimal ratio of BiVO 4/g-C 3N 4. The outstanding performance of the photocatalyst is attributed to synergetic effect of interface Z-scheme heterojunction and high active facets {010} of BiVO 4 nanoplates, which provides an efficient transfer pathway to separate photoinduced carriers meanwhile endows the photocatalysts with strong redox ability. 相似文献
19.
A high-performance photocatalyst, attapulgite/Cu 2O/Cu/g-C 3N 4 (ATP/Cu 2O/Cu/g-C 3N 4), was constructed via a one-pot redox strategy under anoxic calcination. The as-prepared composites were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption-desorption isotherms (BET), photoluminescence emission (PL), and electrochemical impedance spectra (EIS). Results indicate that ultra-fine CuO nanoparticles on the surface of rod-like attapulgite are in-situ reduced by NH 3 gas to generate Cu and minority Cu 2O during the pyrocondensation of melamine. Meanwhile, the generated g-C 3N 4 membrane is uniformly encapsulated on the surface of attapulgite/Cu 2O/Cu to assemble Z-scheme Cu 2O/Cu/g-C 3N 4 heterostructure. ATP/Cu 2O/Cu/g-C 3N 4 shows improved visible light response ability and hole-electron suppression compared with ATP/g-C 3N 4. The photocatalytic performance and mechanism of the obtained photocatalyst for antibiotic degradation were evaluated by UV–Vis spectrometer and liquid chromatograph. ATP/Cu 2O/Cu/g-C 3N 4 can exhibit favorable photocatalytic activity and reusability for chloramphenicol. In addition, h+ and·OH radicals are the main active sites in the photocatalytic process, and Cu species play a vital role in separation and retarding recombination of electron-hole pairs. 相似文献
20.
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
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