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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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Synergetic utilization of photoabsorption and surface facet in crystalline/amorphous contacted BiOCl-Bi2S3 composite for photocatalytic degradation
摘要： Photoabsorption and surface property of semiconductor are two key factors to determine its photocatalytic performance. In this work, BiOCl-Bi2S3 composites composed of Bi2S3 nanoparticles bonded on BiOCl nanoplates enclosed with {001} and {110} crystal facets were synthesized through an in-situ ion exchange method at room temperature. The transformed Bi2S3 made BiOCl-Bi2S3 composites efficient visible light absorption, ensuring the quantity of photoinduced carriers as well as intimate crystalline-amorphous contact interface to benefit the separation of photoinduced carriers. Moreover, BiOCl nanoplates enclosed with {001} and {110} crystal facets can convenient transfer carriers to {001} crystal facets. The photocatalytic performance of BiOCl-Bi2S3 composites was evaluated by the methylene blue photodegradation under visible light irradiation and the results indicate that BiOCl-Bi2S3 composites have good photocatalytic ability due to enhanced light absorption, efficient separation and transfer of carriers. Based on the active species trapping experiments, transient photocurrents, electrochemical impedance spectroscopy and energy band structure, a possible photocatalytic mechanism of methylene blue over the BiOCl-Bi2S3 composites was proposed.
关键词： Surface property,Visible light,BiOCl-Bi2S3,Contact interface,Photocatalytic mechanism,Crystal facet
更新于2025-09-23 15:22:29
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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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Fabrication of vessel–like biochar–based heterojunction photocatalyst Bi2S3/BiOBr/BC for diclofenac removal under visible LED light irradiation: Mechanistic investigation and intermediates analysis
摘要： In this work, a novel, economical and effective vessel–like biochar–based photocatalyst Bi2S3/BiOBr/BC was synthesized by a facile one–pot solvothermal method for the first time. A series of characterization analyses demonstrated the successful preparation of photocatalyst Bi2S3/BiOBr/BC. Furthermore, diclofenac (DCF) as the target contaminant was applied to elucidate the enhanced photocatalytic performance (93.65%, 40 min) under energy–saving visible LED light irradiation. Comparison experiments among different photocatalysts and photoelectrochemical tests results illustrated that excellent photocatalytic performance of Bi2S3/BiOBr/BC 10% might be attributed to the electrons transfer of biochar and higher charge separation efficiency of heterojunction structure. Besides, lower electrical energy per order value indicated photocatalyst/visible LED light system was more energy–saving. Proper photocatalyst dosage (0.6 g/L) and relatively acidic water environment (pH=5.0) would be beneficial to DCF photodegrdation by Bi2S3/BiOBr/BC. Good reusability and stability of Bi2S3/BiOBr/BC were verified via five consecutive recycle experiments. Furthermore, the role of active species was determined through trapping experiments and ·O2– and h+ dominated the photodegradation reaction to mineralize DCF molecules. Eleven main intermediates and four possible photodegradation pathways were proposed by HRMS analysis. Accordingly, photocatalyst Bi2S3/BiOBr/BC would provide potential technical support for emerging pollutant removal in water matrix.
关键词： Diclofenac,Photocatalytic mechanism,Bi2S3/BiOBr/BC,Visible LED light,Degradation pathway
更新于2025-09-19 17:13:59
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A new insight into the enhanced visible light-induced photocatalytic activity of NaNbO3/Bi2WO6 type-II heterostructure photocatalysts
摘要： In this study, a series novel NaNbO3/Bi2WO6 heterojunction composites with a type-II alignment were fabricated via a facile wet impregnation method. The as-prepared photocatalysts were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), diffuse reflectance UV-Vis spectroscopy (DRS), photocurrent (PC) and electrochemical impedance spectroscopy (EIS) analyses. The 30 wt% NaNbO3/Bi2WO6 composite exhibited the best performance in the case of degrading rhodamine B (RhB) aqueous solution under visible light irradiation (λ > 410 nm), which was ～2.5 times and ～40 times that of pure Bi2WO6 and NaNbO3, respectively. The improved photocatalytic performance was further demonstrated by 2-chlorophenol under the same reaction conditions. This may be attributed to the enhanced electron-hole separation efficiency in Bi2WO6 with the assistance of NaNbO3, as well as the dye-sensitization effect of RhB dye itself. Intermediates produced during the reaction and RhB degradation pathway were investigated as well. Radical quenching experiments revealed h+ functioned as well to some degree. Based on experimental results, the potential functioning mechanism was proposed, which is different from previously reported type-II heterostructure systems when Bi2WO6 works as the electron reservoir and O2?· is one of the dominant active species. The as-prepared photocatalyst composite exhibited excellent stability after repetitively running five times. Effects of several operating parameters on the catalyst performance including initial RhB concentration, catalyst dosage, reaction temperature and initial pH were also discussed. This study provides solid evidence for NaNbO3 to be a promising candidate for photocatalysis and gives out a novel photocatalytic mechanism of Bi2WO6-based heterostructures.
关键词： Heterostructure,Photocatalytic mechanism,Photocatalysis
更新于2025-09-10 09:29:36