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Growth Process and CQDs-modified Bi4Ti3O12 Square Plates with Enhanced Photocatalytic Performance
摘要： Bi4Ti3O12 square plates were synthesized via a hydrothermal route, and their growth process was systematically investigated. Carbon quantum dots (CQDs) were prepared using glucose as the carbon source, which were then assembled on the surface of Bi4Ti3O12 square plates via a hydrothermal route with the aim of enhancing the photocatalytic performance. XRD (X-ray powder diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy), UV-vis DRS (diffuse re?ectance spectroscopy), XPS (X-ray photoelectron spectroscopy), FTIR (Fourier transform infrared spectroscopy), PL (photoluminescence) spectroscopy, EIS (electrochemical impedance spectroscopy) and photocurrent spectroscopy were used to systematically characterize the as-prepared samples. It is demonstrated that the decoration of CQDs on Bi4Ti3O12 plates leads to an increased visible light absorption, slightly increased bandgap, increased photocurrent density, decreased charge-transfer resistance, and decreased PL intensity. Simulated sunlight and visible light were separately used as a light source to evaluate the photocatalytic activity of the samples toward the degradation of RhB in aqueous solution. Under both simulated sunlight and visible light irradiation, CQDs@Bi4Ti3O12 composites with an appropriate amount of CQDs exhibit obviously enhanced photocatalytic performance. However, the decoration of excessive CQDs gives rise to a decrease in the photocatalytic activity. The enhanced photocatalytic activity of CQDs-modi?ed Bi4Ti3O12 can be attributed to the following reasons: (1) The electron transfer between Bi4Ti3O12 and CQDs promotes an ef?cient separation of photogenerated electron/hole pairs in Bi4Ti3O12; (2) the up-conversion photoluminescence emitted from CQDs could induce the generation of additional electron/hole pairs in Bi4Ti3O12; and (3) the photoexcited electrons in CQDs could participate in the photocatalytic reactions.
关键词： photocatalytic mechanism,photodegradation of RhB,CQDs@Bi4Ti3O12 composites,Bi4Ti3O12 square plates,CQDs
更新于2025-11-19 16:46:39
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Facile preparation of antifouling g-C3N4/Ag3PO4 nanocomposite photocatalytic polyvinylidene fluoride membranes for effective removal of rhodamine B
摘要： A simplified strategy for facilely fabricating antifouling graphite carbon nitride/silver phosphate (g-C3N4/Ag3PO4) nanocomposite photocatalytic polyvinylidene fluoride (PVDF) porous membranes was developed for effective removal of rhodamine B (RhB). g-C3N4/Ag3PO4 heterojunction was strongly fixed to the interior of the PVDF membranes via phase inversion method. The membrane structure was analyzed by Fourier transform spectrophotometer (FT-IR). The morphology of the prepared membranes was investigated using scanning electron microscopy (SEM), EDX-mapping and atomic force microscopy (AFM), respectively. All prepared nanocomposite photocatalytic PVDF membranes exhibited a typically porous structure, and g-C3N4/Ag3PO4 nanocomposites were well dispersed inside the membranes. The obtained g-C3N4/Ag3PO4 heterojunction nanoparticle decorated PVDF membrane had a lower water contact angle of 79o and higher porosity of 85% than that of other two control membranes. The nanocomposite photocatalytic PVDF porous membranes had extremely high permeation flux over 1,083 L·m?2·h?1, and could be used for the removal of RhB. The removal efficiency of g-C3N4/Ag3PO4-PVDF membranes towards RhB solution under visible light irradiation reached 97%, higher than that of the pure PVDF membranes (41%) and g-C3N4-PVDF membranes (85%). Remarkably, the flux performance and flux recovery ratio (FRR) of membranes revealed that the g-C3N4/Ag3PO4-PVDF membranes could recover high flux after fouling, which presented better fouling resistance. Furthermore, the fabricated antifouling g-C3N4/Ag3PO4 nanocomposite photocatalytic PVDF porous membranes exhibited excellent recyclability. Therefore, it is expected that g-C3N4/Ag3PO4-PVDF membranes could provide an energy-saving strategy for effective removal of organic dyes wastewater and have a great potential for practical wastewater treatment in the future.
关键词： PVDF Membranes,Anti-fouling Properties,g-C3N4/Ag3PO4 Heterojunction,Removal RhB
更新于2025-09-23 15:22:29
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A facile synthesis of nano-layer structured g-C3N4 with efficient organic degradation and hydrogen evolution using a MDN energetic material as the starting precursor
摘要： The construction of a high-performance g-C3N4 photocatalyst through a facile and green synthesis method remains a great challenge for H2 production and organic pollutants degradation. In this work, we developed a nano-layer structured g-C3N4 (NL-CN) photocatalyst with a 230 m2/g surface area via the thermal polymerization method using melaminium dinitrate (MDN), which is one of the more energetic materials, as the precursor. The energy coming from the drastic decomposition of nitrate anions in MDN caused the thick layers of bulk CN to be exfoliated to produce many much-thinner nano-layers when at 500 °C for 2 h, which obviously elevated the surface area of the g-C3N4. The resultant NL-CN displays a superior visible-light H2-generation and rhodamine B (RhB) photo-degradation efficiency (λ > 420 nm) compared to those of bulk g-C3N4 (CN) prepared through heating melamine because of the nano-layered structures, which lead to higher specific surface areas, a rapid charge transfer efficiency and a higher redox potential. These results demonstrate that the utilization of MDN as a starting material provides a new opportunity for the facile and green synthesis of high-efficiency nanostructured g-C3N4 photocatalysts with lower energy consumption and environmental pollution levels.
关键词： H2 production,Nano-layers,Melaminium dinitrate,g-C3N4,Photocatalyst,RhB degradation
更新于2025-09-23 15:22:29
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Facile two-step synthesis of porous carbon nitride with enhanced photocatalytic activity using a soft template
摘要： In this study, we successfully synthesized a thin-slice layer of graphitic carbon nitride (g-C3N4) with abundant irregular holes by a facile two-step way using Pluronic P123 as a template (CN-P123-x, where x represents the mass ratio of melamine to Pluronic P123). The characterization data suggest that the introduction and removal of Pluronic P123 altered the chemical material structure of the carbon nitride. The CN-P123-x presented lamellar structure with irregular holes, whereas H-g-C3N4 (g-C3N4 prepared using a mild hydrothermal and calcination method without Pluronic P123 or HCl) has a dense blocky structure. Additionally, the prepared CN-P123-x exhibited an effective Rhodamine B (RhB) degradation rate of 98.7% within 40 min of illumination. The optimal photocatalytic activity of CN-P123-6 for degrading RhB was 13.9 times greater than that of H-g-C3N4 in terms of the kinetic constant. Furthermore, the H2 evolution rate of CN-P123-6 can reach 1074.9 μmol?g?1?h?1, whereas that of H-g-C3N4 is only 3.1 μmol?g?1?h?1. It is worth noting that the adoption of HCl (H-g-C3N4-HCl) and Pluronic P123 (CN-P123-6 without HCl) alone has no insignificant effect on photocatalytic performance. The intensive activities are on account of the irregular pores in the thin slice, which increase the specific surface area of the sample and provide additional active sites for reaction. This work provides an excellent basis for improving the performance of the photocatalytic degradation and hydrogen production of carbon nitride.
关键词： Rhodamine B (RhB),H-g-C3N4,hydrogen production,photocatalytic degradation,CN-P123-x
更新于2025-09-23 15:22:29
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Synthesis of Zr-based MOF nanocomposites for efficient visible-light photocatalytic degradation of contaminants
摘要： A novel ternary complex photocatalyst (UiO-66/g-C3N4/Ag) was fabricated by chemical protonation coating and photodeposition and its physicochemical parameters, crystal morphology, and electrochemical properties characterized using a series of techniques. Proper addition of g-C3N4 and Ag effectively enhanced the separation and mobility of photoinduced charge and improved the visible-light absorption and thereby the catalytic performance. Degradation experiments on target contaminants such as Rhodamine B (RhB) dye and 2,4-dichlorophenoxyacetic acid (2,4-d) showed that the photocatalytic ability of UiO-66/g-C3N4/Ag(15) was greatly increased compared with the parent material. Moreover, the composite could be regenerated by a simple ethanol washing process and exhibited stability and high reusability over six cycles. Finally, experiments on trapping of active species revealed that superoxide radicals (·O2?), holes (h+), and hydroxyl radicals (·OH) were primarily responsible for the photodegradation of RhB and 2,4-d.
关键词： UiO-66/g-C3N4/Ag,Photocatalysis,2,4-d,RhB,Catalytic mechanism
更新于2025-09-23 15:21:21
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One-pot biosynthesis of SnO2 quantum dots mediated by Clitoria ternatea flower extract for photocatalytic degradation of rhodamine B
摘要： In this study, SnO2 quantum dots (QDs) have been successfully biosynthesized using Aparajitha (Clitoria ternatea) flower extract as the green reducing agent and then used as effective photocatalysts for the degradation of rhodamine B (RhB) under UV light irradiation. Clitoria ternatea flower extract contains flavanols and flavonoids, which can serve as reducing agents to convert Sn2+ precursors into Sn° NPs, which are then oxidized to 4–10 nm SnO2 QDs at 400 °C for 2 h. A blue shift in the adsorption wavelength of biosynthesized SnO2 QDs (3.66 eV) in comparison with bulk SnO2 (3.54 eV) is obtained, which can reduce the electron–hole recombination rate of SnO2. In addition, the specific surface area of SnO2 QDs is almost two times higher than that of bulk SnO2, resulting in the acceleration of photocatalytic degradation efficiency and rate of RhB under UVB light irradiation. The photodegradation performance of RhB over SnO2 QDs is highly dependent on several parameters, including H2O2 concentration, catalyst dosage, and pH. The liquid chromatography-mass spectrometric spectra and radical scavenger experiments indicate that the hydroxyl radicals play a crucial role in photodegradation, which can undergo N-deethylation and ring cleavage reactions to produce intermediates of N, N-diethyl-N’-ethylrhodamines, dihydroxybenzoic acid, and maleic acid. Moreover, a possible reaction mechanism for RhB photodegradation over SnO2 QDs is proposed. Results obtained in this study clearly indicate that the extract is an effective bioreagent to develop the green chemistry for the one-pot synthesis of SnO2 QDs photocatalysts for the degradation of pollutants in aqueous solutions.
关键词： Rhodamine B (RhB),Clitoria ternatea flower extract,SnO2 quantum dots,Photocatalytic activity
更新于2025-09-23 15:19:57
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Boosting visible light photocatalytic activity via impregnation-induced RhB-sensitized MIL-125(Ti)
摘要： The visible light driven pollutant degradation by photocatalysis is one of the most effective and environmentally friendly strategies, which urgently requires the highly efficient catalysis. In this study, the RhB-sensitized MIL-125(Ti) photocatalyst (RhB/MIL-125) was obtained by post-impregnation strategy in dark, owing to its remarkable adsorption and structure properties of MIL-125(Ti). The nanostructure, morphology and optical properties of as-prepared RhB/MIL-125 catalyst were characterized by various physicochemical methods in detail. It was found that the RhB was successfully incorporated into the MIL-125(Ti) matrix. Excitingly, the obtained RhB-sensitized MIL-125(Ti) showed a boosted photocatalytic performance with the removal rate of MO beyond 90% in 60 minutes under visible light (λ > 420 nm) and exhibited the well stability during recycle tests. The hole (h+) and superoxide free radical (O2??) were the key reactive species during the photodegradation process and the possible photocatalytic mechanism of RhB/MIL-125 for MO degradation was proposed. Our new photocatalyst can inspire the in-depth understanding in the visible light driven process and accelerate the nanoporous materials for real-life energy and environmental applications.
关键词： RhB-sensitized MIL-125,MIL-125(Ti),photocatalytic mechanism,photocatalytic performance
更新于2025-09-19 17:15:36
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Enhanced photocatalytic activity of SiC modified by BiVO <sub/>4</sub> under visible light irradiation
摘要： SiC-BiVO4-P and SiC-BiVO4-H composites have been prepared by precipitation method and hydrothermal method, respectively. Rod-like BiVO4 particles dispersed on the surface of micro-sized SiC particles homogeneously in SiC-BiVO4-H. Due to the formed heterostructure between BiVO4 and SiC, photo-generated electrons and holes were effectively separated. Under visible light irradiation, SiC-BiVO4-H exhibited the best performance for photocatalytic oxidation of Rhodamine B, achieved about 7.5 times improvement in photocatalytic degradation rate constants compared with that of the pristine SiC powder. The possible photocatalysis mechanism of SiC/BiVO4 related to the band positions of the semiconductors under visible light irradiation was also discussed in detail. In addition, the radicals trapping experiments revealed that all three radicals (holes, OH, and O2-) play an important role in the Rhodamine B degradation.
关键词： SiC,BiVO4,RhB,heterostructure,visible light
更新于2025-09-19 17:15:36
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Equilibrium and kinetic modelling of adsorption of Rhodamine B on MoS2
摘要： The recent emergence of layered MoS2, which is an earth-abundant material, has gained increasing attention in various fields. In this work, MoS2 is fabricated via a simple hydrothermal method with different sulfur precursors. The effect of S source on the morphologies and adsorption capacities of Rhodamine B (RhB) onto MoS2 were investigated. The results indicated that the MoS2 prepared by CH4N2S exhibited the highest adsorption capacity. The N2 sorption isotherm indicated that the as-prepared MoS2-CH4N2S is a mesoporous microsphere. In addition, the adsorption process can be well described by the Langmuir isotherm model and the pseudo second-order model. The intra-particle diffusion model was also employed to analyze the adsorption mechanisms, which demonstrated that the intra-particle diffusion within the mesopores played an important role in the overall adsorption process. Based on these results, MoS2-CH4N2S obtained in this work can be served as a promising candidate for dye removal in wastewater.
关键词： adsorption kinetics,dye adsorption,adsorption mechanisms,Rhodamine B (RhB),MoS2
更新于2025-09-10 09:29:36
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Degradation of Rhodamine B Under Visible-Light by Cu-Doped ZnAl Layered Double Hydroxide
摘要： The Cu-doped ZnAl layered double hydroxides (LDH) were papered by coprecipitation. The prepared samples were characterized by mutiple techniques including X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse-re?ectance spectroscopy (UV-vis DRS). The doping of Cu2+ into the LDH sheets results in formation of the distorted CuO6 octahedrons which contribute for the excitation of electrons under visible light. The doped Cu2+ also serves as photo-generated charges separator and improves the visible-light-driven photocatalytic activity of ZnAl LDH. A degradation mechanism based on the hydroxyl radical as the active species was proposed.
关键词： RhB Degradation,Visible Light,Copper-Doping,Layered Double Hydroxides
更新于2025-09-09 09:28:46