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Bio-inspired green synthesis of zinc oxide nanoparticles using Abelmoschus esculentus mucilage and selective degradation of cationic dye pollutants
摘要： In this study, biogenic zinc oxide nanoparticles (ZnO NPs) were fabricated via a green synthetic strategy using Abelmoschus esculentus (okra) mucilage. The NPs were characterized by Fourier transform infrared spectroscopy, Fourier transform-Raman, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, X-ray diffraction (XRD), thermogravimetry, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, high resolution transmission electron microscopy, and zeta potential analyses. The XRD pattern confirmed the hexagonal wurtzite structure of ZnO. The morphology of the NPs was uneven where they comprised heterogeneous particles with uniform spheres that had an average size of 29 nm, and elongated and rod-like structures measuring 70 nm. We proposed a possible mechanism for the formation of Zn5(OH)6(CO3)2 micro-flakes and ZnO. The photocatalytic activities of the synthesized ZnO NPs was tested during the degradation of organic dyes comprising methylene blue, rhodamine B, Congo red, and methyl orange in aqueous solutions. The ZnO NPs were capable of the selective photodegradation of the target cationic dyes, where 125 mg of the catalyst removed 100% of the methylene blue solution (32 mg/L) within 60 min and 100 mg was required for the complete removal of rhodamine B (9.5 mg/L) within 50 min. Liquid chromatography-mass spectrometry analysis was conducted to confirm the photodegradation results. Thus, we developed a facile, economic, and green method for the production of ZnO for use as a photocatalyst.
关键词： Abelmoschus esculentus,Photocatalytic study,ZnO nanoparticle
更新于2025-11-14 15:16:37
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AIP Conference Proceedings [Author(s) 2ND INTERNATIONAL CONFERENCE ON CHEMISTRY, CHEMICAL PROCESS AND ENGINEERING (IC3PE) - Yogyakarta, Indonesia (14 August 2018)] - Enhanced photocatalytic activity of WO3 nanoparticles loaded with carbon
摘要： Enhanced photocatalytic activity of WO3 was attempted by carbon nanodots (C-dots) loading. C-dots were prepared using citric acid and urea for enhancing photocatalytic activity of WO3. Physicochemical character of C-dots was studied by fluorescence spectrophotometry and for the modified WO3, evaluation was studied by using x-ray diffraction (XRD) and scanning electron microscope (SEM). Effect of varied citric acid: urea ratio to photocatalytic activity was evaluated in methylene blue photodegradation. Increasing photocatalytic activity was achived by higher intensity in blue color range that obtained by higher urea molar ratio. Kinetics of reaction obey pseudo-first order and pseudo-second order reaction. Reaction reached 80% MB degradation for an hour treatment for 50mM of methylene blue solution.
关键词： photocatalytic activity,methylene blue photodegradation,WO3 nanoparticles,carbon nanodots
更新于2025-11-14 15:15:56
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Study on heterogeneous photocatalytic ozonation degradation of ciprofloxacin by TiO2/carbon dots: Kinetic, mechanism and pathway investigation
摘要： In this study, the objective was mainly focusing on the mechanism investigation of ciprofloxacin (CIP) degradation by photocatalytic ozonation process which carried out by ozone and TiO2 with a low content of carbon-dots (CDs) under simulated sunlight irradiation. The physicochemical properties of the prepared photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM) X-ray photoelectron spectroscopy (XPS) and zeta potential. Comprehensive investigation has proven the process to be efficient in the removal of CIP with high yield of reactive species (?OH, O2 ?—, h+, etc.). Kinetic model on pH investigation found out a repulsive force between the photocatalysts and CIP intensified with the increasing pH, so did the production rate of hydroxyl radicals (?OH), while eventually reached a balance and achieved a maximum degradation rate. The results indicated that the enhancement mechanism was triggered by the photoexcited electron accumulated on CDs and transferred by ozone, resulting in the continuous generation of h+, O3 ? — and O2 ? —. Possible photocatalytic ozonation degradation pathways of CIP were proposed according to the identifications of intermediates using high-resolution accurate-mass spectrometry (HRAM) LC-MS/MS.
关键词： ciprofloxacin,reactive species,carbon-dots,photocatalytic ozonation,transformation pathway
更新于2025-11-14 15:15:56
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Preparation and immobilization of zinc sulfide (ZnS) nanoparticles on polyvinylidene fluoride pellets for photocatalytic degradation of methylene blue in wastewater
摘要： ZnS nanoparticles with 90 nm diameter were synthesized by low-temperature method and immobilized onto the surface of polyvinylidene fluoride (PVDF) pellets prepared by phase inversion method. Results by FTIR and X-ray photoelectron spectroscopy revealed that the ZnS nanoparticles were immobilized tightly on the PVDF surface without their release and losing photocatalytic activity. The UV-absorption spectra showed that the PVDF matrix had no adverse effect on the optical properties of ZnS nanoparticles. Due to large size (5 mm) and excellent mechanical stability, the PVDF-ZnS pellets could be easily dispersed in the photocatalytic reactor treating methylene blue solution. The removal efficiency of the methylene blue with the PVDF-ZnS pellets was higher (more than 95%) than that observed by the control PVDF pellets or ZnS nanoparticles tested. No change in the removal efficiency was observed as the PVDF-ZnS pellets were reused by performing photocatalytic tests at the same experimental conditions repeatedly.
关键词： Reusability,Polymer carrier,Zinc sulfide,Immobilization,Phase inversion,Photocatalytic degradation
更新于2025-11-14 15:14:40
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Fabrication of MoS2/TiO2 heterostructure with enhanced photocatalytic activity
摘要： Two dimensional nanophotocatalysts MoS2/TiO2 with tunable decoration amount of MoS2 nanosheets were fabricated through hydrothermal route. The microstructure and photocatalytic behavior of as?prepared samples were characterized by X?ray diffraction, scanning electron microscope, transmission electron microscopy, UV?vis diffuse reflectance spectra, electrochemical workstation, dye degradation and water splitting experiment. The result shows that these composites exhibited enhanced photocatalytic activity for RhB degradation and hydrogen generation. Nearly 95% photocatalytic degradation of RhB was obtained for 2 h and 1.93 mmol g?1 h?1 of hydrogen production rate was achieved over MoS2/TiO2 at a MoS2 content of 10 wt%. And the corresponding photocurrent density of composite photoelectrode was 5?fold higher than that of pristine TiO2 architectures. It is believed that the boosting photocatalytic performance of heterostructure could be ascribed to the synergetic effect between the MoS2 and TiO2, which accelerated the separation and migration efficiency of charge carries as well as enhanced the light?harvest efficiency.
关键词： photocatalytic activity,photogenerated electron?hole pairs,heterostructure,photocatalyst,MoS2/TiO2
更新于2025-11-14 15:13:28
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Photocatalytic performance of TiO2 thin film decorated with Cu2O nanoparticles by laser ablation
摘要： Cu2O nanoparticles decorated TiO2 thin films were fabricated by laser ablation. The effects of Cu2O nanoparticles on the structure, optical properties and photocatalytic performance of TiO2 thin film were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectrometer system, optical absorption and photocatalytic evaluation system, respectively. XRD patterns indicate that the decoration has the effect of lowering the grain orientation of Cu2O. The photocatalytic performance in hydrogen generation of Cu2O decorated TiO2 composite thin film was significantly improved compared with that of either Cu2O nanoparticles or TiO2 single layer thin film with 1.70 and 1.77 times, respectively. The oxidation of Cu2O was demonstrated to dominate the photocatalytic performances of Cu2O/TiO2 composite thin films by varying the laser ablation powers.
关键词： Heterojunction,Cu2O nanoparticles,Laser ablation,Photocatalytic performance,TiO2 thin film
更新于2025-10-22 19:40:53
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Zinc ions modified InP quantum dots for enhanced photocatalytic hydrogen evolution from hydrogen sulfide
摘要： Through direct addition of inorganic zinc ions into the solution of indium phosphide quantum dots (InP QDs) at ambient environment, we here present a facile but effective method to modify InP QDs for photocatalytic hydrogen evolution from hydrogen sulfide (H2S). X-ray diffraction patterns and transmission electron microscopic images demonstrate that zinc ions have no significant influence on the crystal structure and morphology of InP QDs, while X-ray photoemission spectra and UV–Vis diffuse and reflectance spectra indicate that zinc ions mainly adsorbed on the surface of InP QDs. Photocatalytic results show the average hydrogen evolution rate has been enhanced to 2.9 times after modification and H2S has indeed involves in the hydrogen evolution process. Steady-state and transient photoluminescence spectra prove that zinc ions could effectively eliminate the surface traps on InP QDs, which is crucial to suppress the recombination of charge carriers. In addition, the electrostatic interaction between zinc ions and the surface sulfide from InP QDs could mitigate the repulsion between QDs and sulfide/hydrosulfide, which may promote the surface oxidative reaction during photocatalysis. This work avoids the traditional harsh and complicated operations required for surface passivation of QDs, which offers a convenient way for optimization of QDs in photocatalysis.
关键词： Hydrogen sulfide,Photocatalytic hydrogen evolution,InP quantum dots,Surface modification
更新于2025-10-22 19:38:57
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Adsorption and photocatalytic oxidation of ibuprofen using nanocomposites of TiO2 nanofibers combined with BN nanosheets: Degradation products and mechanisms
摘要： This study investigated the adsorption and photocatalytic activity of TiO2-boron nitride (BN) nanocomposites for the removal of contaminants of emerging concern in water using ibuprofen as a model compound. TiO2 nanofibers wrapped by BN nanosheets were synthesized by electrospinning method. Characterization of the nanocomposite photocatalysts indicated the BN nanosheets improved the light absorbance and reduced the recombination of the photoexcited charge carriers (e- and h+). The photocatalytic oxidation products and mechanisms of ibuprofen by the TiO2-BN catalysts were elucidated using a multiple analysis approach by high performance liquid chromatography, ultraviolet absorbance, dissolved organic carbon, fluorescence excitation-emission matrices, and electrospray ionization–liquid chromatography–tandem mass spectrometry. The experimental results revealed that the photocatalytic oxidation by the TiO2-BN nanocomposites is a multi-step process and the interactions between ibuprofen molecules and the TiO2-BN nanocomposites govern the adsorption process. The increasing BN nanosheet content in the TiO2 nanofibers facilitated the breakdown of ibuprofen degradation intermediates (hydroxyibuprofen, carboxyibuprofen, and oxypropyl ibuprofen). Kinetic modeling indicated both adsorption and photocatalytic oxidation of ibuprofen by the TiO2-BN nanocomposites followed the first-order kinetic model. The photocatalytic oxidation rate increased with the increasing BN content in the nanocomposite catalysts, which was attributed to the enhanced light absorption capacity and the separation efficiency of the photoexcited electron (e-)-hole (h+) pairs. Multiple photocatalytic cycles were conducted to investigate the reusability and regeneration of the nanofibers for ibuprofen degradation.
关键词： adsorption,titanium dioxide boron-nitride nanocomposites,photocatalytic degradation mechanisms,degradation intermediates,photocatalytic oxidation
更新于2025-09-23 15:23:52
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Sub-5 nm Ultra-Fine FeP Nanodots as Efficient Co-Catalysts Modified Porous g-C <sub/>3</sub> N <sub/>4</sub> for Precious-Metal-Free Photocatalytic Hydrogen Evolution under Visible Light
摘要： Sub-5 nm ultra-fine iron phosphide (FeP) nano-dots-modified porous graphitic carbon nitride (g-C3N4) heterojunction nanostructures are successfully prepared through the gas-phase phosphorization of Fe3O4/g-C3N4 nanocomposites. The incorporation of zero-dimensional (0D) ultra-small FeP nanodots co-catalysts not only effectively facilitate charge separation but also serve as reaction active sites for hydrogen (H2) evolution. Herein, the strongly coupled FeP/g-C3N4 hybrid systems are employed as precious-metal-free photocatalysts for H2 production under visible-light irradiation. The optimized FeP/g-C3N4 sample displays a maximum H2 evolution rate of 177.9 μmol h?1 g?1 with the apparent quantum yield of 1.57% at 420 nm. Furthermore, the mechanism of photocatalytic H2 evolution using 0D/2D FeP/g-C3N4 heterojunction interfaces is systematically corroborated by steady-state photoluminescence (PL), time-resolved PL spectroscopy, and photoelectrochemical results. Additionally, an increased donor density in FeP/g-C3N4 is evidenced from the Mott-Schottky analysis in comparison with that of parent g-C3N4, signifying the enhancement of electrical conductivity and charge transport owing to the emerging role of FeP. The density functional theory calculations reveal that the FeP/g-C3N4 hybrids could act as a promising catalyst for the H2 evolution reaction. Overall, this work not only paves a new path in the engineering of monodispersed FeP-decorated g-C3N4 0D/2D robust nanoarchitectures but also elucidates potential insights for the utilization of noble-metal-free FeP nanodots as remarkable co-catalysts for superior photocatalytic H2 evolution.
关键词： transition-metal phosphides,g-C3N4,co-catalysts,precious-metal-free,photocatalytic H2 production
更新于2025-09-23 15:23:52
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Z-Scheme 2D/2D Heterojunction of Black Phosphorus/Monolayer Bi2WO6 Nanosheets with Enhanced Photocatalytic Activities
摘要： Black phosphorus (BP), a star-shaped two-dimensional material, has attracted considerable attention owing to its unique chemical and physical properties. BP shows great potential in photocatalysis area because of its excellent optical properties; however, its applications in this field have been limited to date. Herein, we design and fabricate a Z-Scheme heterojunction of 2D/2D BP/monolayer Bi2WO6 (MBWO) by a simple and effective method. The BP/MBWO heterojunction exhibits enhanced photocatalytic performance in photocatalytic water splitting to produce H2 and NO removal to purify air; the highest H2 evolution rate of BP/MBWO is 21042 μmol g-1, is 9.15 times that of pristine MBWO and the NO removal ratio was as high as 67%. A Z-Scheme photocatalytic mechanism is proposed based on monitoring of ?O2?, ?OH, NO2, and NO3? species in the reaction. This work broadens applications of BP and highlights its promise in the treatment of environmental pollution and renewable energy issues.
关键词： hydrogen production,photocatalytic,Black phosphorus,2D/2D heterojunction,Z-Scheme
更新于2025-09-23 15:23:52