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Preparation of La doped ZnO ceramic nanostructures by electrospinning–calcination method: Effect of La3+ doping on optical and photocatalytic properties
摘要： Ceramic nanostructures of ZnO doped with La3+ ions (0.02%, 1%, 2% and 4%) were prepared by electrospinning-calcination method. Polyvinylpyrrolidone (PVP) was used as an additional polymer to promote the electrospinning. And, the intermediate electrospun products were processed thermically at 700 °C for 3 h. The produced materials were characterized morphologically and structurally by using scanning/transmission electron microscopy (SEM/TEM) and X-ray diffraction (XRD). The XRD patterns showed the successful incorporation of La ions in the hexagonal wurtzite structure of ZnO. Optical band gaps of these ceramic nanostructures were estimated from reflectance data using Kubelka-Munk theory and were found to vary from 2.589 to 2.889 eV, depending on La3+ doping concentration. Photoluminescence spectra of undoped/doped ZnO with different contents of La3+ ion were investigated. The decay curves for the La3+ ion doped ZnO nanostructures were measured and the average lifetime was found to increase from 2.69 to 2.80 ns when La3+ content increased from 0 to 4%. The photocatalytic activity of doped products (ZnO:La) was investigated by using Congo-Red dye as a probe molecule for degradation under UV-light. Maximal color removal efficiency (97.63%) was observed experimentally for ZnO doped with 2% La3+ in dosage of 0.283 g/L. Finally, the recovered catalyst was thermally activated at 700 °C (1 h) and then successfully reused for the dye photodegradation.
关键词： La-doped ZnO nanostructures,Photodegradation kinetics,Photocatalyst,Optical properties,Electrospinning
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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Synthesis of multifunctional photocatalyst vanadium oxide/activated carbon via in situ utilization of stone coal ore
摘要： In this work, activated carbon (AC), vanadium oxide (V2O5), and V2O5/AC photocatalyst were prepared by in situ utilization of stone coal ore for the first time. The synthesis conditions for activated carbon (AC) and V2O5/AC were thoroughly investigated via orthogonal experiments and single factor experiments, respectively. The obtained optimal parameters could be directly adopted in practical application about utilization of stone coal ore. The optimal deashing experimental parameters for stone coal ore were: HF concentration of 15%, H2SO4 concentration of 15%, acid leaching temperature of 85 °C, and acid leaching time of 2 h. The as-prepared activated carbon from stone coal ore could be applied to the removal of methylene blue. The as-prepared V2O5/AC photocatalyst possessed a highly visible-light-driven photocatalytic activity for the removal of Rhodamine B (RhB) dye. The RhB degradation ratio could reach to 90.0% after only 3 h photocatalytic reaction. This photocatalyst would be possibly applied to treatment other organic dye wastewater. Actually, this work would extend the application field of stone coal ore. Most importantly, we hope the proposed new concept that in situ utilization of ore can be widely spread and applied.
关键词： Stone coal ore,Photocatalyst,V2O5,Activated carbon,In situ utilization
更新于2025-09-23 15:22:29
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The flower-like heterostructured Fe2O3/MoS2 coated by amorphous Si-Oxyhydroxides: An effective surface modification method for sulfide photocatalysts in photo-Fenton reaction
摘要： The semiconductor photocatalytic technology is an important approach for solving the energy and environmental problems by only harnessing solar energy. Herein, we employ a facile hydrothermal method to prepare 3D flower-like Fe2O3/MoS2 heterostructures, which perform a high efficient photocatalytic property on photodegrading 20 mg/L methyl blue (MB) solution within 20 min, over 10 times of bare Fe2O3 nanoparticles. In addition, we first propose a surface modification method using amorphous Si-oxyhydroxides (SiOxH) as coating layer to protect the sulfide photocatalysts from corrosion in photo-Fenton reaction. As a result, the SiOxH-Fe2O3/MoS2 nanocomposites show good stability and high efficient decomposition behavior in photo-Fenton reaction, while the MoS2 nanosheets of as-prepared Fe2O3/MoS2 heterostructures without SiOxH modification have been almost all corroded away.
关键词： Photocatalyst,Heterostructure,Characterization,Surface modification.
更新于2025-09-23 15:22:29
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Characterization and removal of antibiotic residues by NFC-doped photocatalytic oxidation from domestic and industrial secondary treated wastewaters in Meric-Ergene Basin and reuse assessment for irrigation
摘要： Antibiotics are important contaminants that have become an increasingly big problem due to the discharge of the receiving environment. The presence of these organic based pollutants in influent wastewater can inhibit the biological processes and resist to degradation in wastewater treatment plants. Moreover, the consumption of agricultural products, irrigated with water containing antibiotic residues, leads to major harmful effects to the human body through the food chain. In this study; firstly, a conventional characterization was made in terms of COD, TOC, SS, color and of antibiotic residue characterization of untreated raw (influent) and biologically treated (effluent) water from domestic and industrial wastewater treatment plants located in the Meri?-Ergene Basin. After that, photocatalytic activity test was run under visible light for selected antibiotics (Erythromycin, Ciprofloxacin, Sulphametoxasol) which were detected by HPLC MS/MS in excess amount. Finally, for the photocatalytic oxidation, a new generation NFC (Nitrogen-Floride-Carbon)-doped titanium dioxide photocatalyst, which has never been studied in the literature before, was prepared according to the sol-gel method without using thermal processing. Photocatalysts were characterized by UV–vis DRS reflectance and Laser Raman Spectra measurements. All other analyzes were made according to the standard methods. Considering the conventional characterization results; investigated domestic wastewaters exhibited moderate characteristics while industrial wastewater samples had strong characteristics in terms of COD, TOC and SS pollution in accordance with the literature. By the way, contrary to expectations, antibiotic residue results have proved that the effluent wastewater contains more antibiotics than the influent. This can be explained by the fact that, some antibiotics in domestic wastewaters are probably already trapped in feces and cannot be purified by conventional systems since they are released after biological treatment, as mentioned similar studies in the literature. Moreover, by means of 7 h NFC-doped photocatalytic oxidation under visible light, beside approximately % 62 to %79 COD and 62%–86% TOC removal, %99 to %100 removal of antibiotic residue was provided. According to these results, domestic and industrial secondary treated wastewaters in Meric-Ergene Basin can be advance treated, succesfully, with NFC-doped photocatalyst to remove antibiotic residues besides conventional pollutants. This result show that Meri?-Ergene discharge criteria determined by Forest and Water Ministry of Turkey can be provided with this new type photocatalytic process and healthy reuse of this river for irrigation will be possible.
关键词： Advanced oxidation processes,Domestic/industrial wastewater,Solvent-casting method,UV,Antibiotic,Photocatalyst,NFC-doped TiO2
更新于2025-09-23 15:22:29
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Facile Synthesis of g-C3N4/CdWO4 with Excellent Photocatalytic Performance for the Degradation of Minocycline
摘要： A novel g-C3N4/CdWO4 composite was formed by hydrothermal process and utilized for the removal of Minocycline (MC) antibiotic under visible light exposure. The XRD patterns of synthesized sample reveal the pure crystalline structure and phase of g-C3N4/CdWO4. The SEM images of g-C3N4/CdWO4 showed regular short rod structure with diameter in the range of 20-60 nm. These images also showed that the g-C3N4/CdWO4 structure has well contacted surfaces which enhanced the interfacial transfer of charge as a result of which the performance of photocatalyst was improved. The energy dispersive spectroscopy (EDS) images of g-C3N4, CdWO4 and g-C3N4/CdWO4 conclude that there were no impurities in the synthesized samples. SEM and EDS results confirm the interface interaction develop between g-C3N4 and CdWO4 due to hybridization. The FTIR spectrum of composite showed that the composite formed had extensively conjugated system and the band gap energies calculated for CdWO4, g-C3N4 and g-C3N4/CdWO4 were 3.31 eV, 2.67 eV and 2.71 eV respectively. A remarkable drop in photoluminescence intensity of g-C3N4/CdWO4 was observed as compared to pure g-C3N4 and CdWO4 which led to lower recombination rate of photo-induced charge carriers and hence a higher photocatalytic performance for the degradation of minocycline under visible-light irradiation.
关键词： Photocatalytic Performance,Photocatalyst,Recombination Rate,Charge Carries,minocycline
更新于2025-09-23 15:22:29
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The photocatalytic degradation kinetics of gaseous formaldehyde flow using TiO2 nanowires
摘要： A high performance TiO2 nanowires photocatalyst was successfully prepared by a hydrothermal method to decompose gaseous formaldehyde into CO2 and H2O in a homemade tube reactor without secondary pollution under UV irradiation. The photocatalytic oxidization (PCO) kinetics fit well with the traditional Langmuir-Hinshelwood-Hougen-Watson (LHHW) model. Multiple parameters including formaldehyde concentration, flow rate, and light intensity were monitored online and proved to be key factors affecting the rate in the photocatalytic reactions. The crystallinity of photocatalyst and its surface reactive site density determined the adsorption equilibrium constant (KHCHO) of formaldehyde on TiO2. The experimental results show that the degradation kinetics of mobile gas-phase formaldehyde by TiO2 nanowires did not strictly conform to the first-order reaction kinetics, and its photocatalytic degradation rate increases with the increase of ultraviolet LED irradiation intensity. It takes only 8.6 minutes to completely degradate formaldehyde at a flow rate of 50 ml/min by 50 mg 700TiO2, and the reaction performance remains unchanged during the decomposing process of 1200 minutes.
关键词： reaction kinetics,formaldehyde,Titanium oxide nanowires,photocatalyst,photocatalytic oxidization
更新于2025-09-23 15:22:29
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Development of Titanium Dioxide (TiO <sub/>2</sub> )-Embedded Buoyant Photocatalyst Balls Using Expanded Polystyrene
摘要： A new immobilization technique of nanoscale TiO2 powders to expanded polystryrene (EPS) balls with temperature-controlled melting method was developed for mass production, and the characterization of TiO2 powder-embedded EPS (TiEPS) balls was evaluated. Based on the scanning electron microscope (SEM) images and associated energy-dispersive X-ray spectroscopy (EDX) analysis, the components of intact EPS balls are carbon and oxygen whereas those of TiEPS balls are carbon, oxygen, and titanium, indicating that TiO2 powders were embedded on the surface of EPS balls. As also evident by the X-ray diffraction (XRD) and FTIR analyses, no significant changes in crystalline structure of TiO2 powders embedded on the EPS balls were found during the preparation and application processes of TiEPS balls. These characterization results indicated that the patches of TiO2 powders were soundly impregnated over the surface of EPS balls without the significant changes in crystalline structure of TiO2 powders and both structural changes and deformation of EPS polymer.
关键词： FTIR,TiO2-Embedded EPS Balls,Photocatalyst,Methylene Blue (MB),Expanded Polystyrene (EPS),X-ray Spectroscopy,TiO2
更新于2025-09-23 15:22:29
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Exfoliated Molybdenum Disulfide Encapsulated in a Metal Organic Framework for Enhanced Photocatalytic Hydrogen Evolution
摘要： An exfoliated MoS2 encapsulated into metal-organic frameworks (MOFs) was fabricated as a promising noble-metal-free photocatalyst for hydrogen production under visible light irradiation. The as-synthesized samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) surface analysis. It is well known that bulk MoS2 is unsuitable for photocatalysis due to its inadequate reduction and oxidation capabilities. However, exfoliated MoS2 exhibits a direct band gap of 2.8 eV due to quantum confinement, which enables it to possess suitable band positions and retain a good visible-light absorption ability. As a result, it is considered to be an encouraging candidate for photocatalytic applications. Encapsulating exfoliated MoS2 into MOF demonstrates an improved visible light absorption ability compared to pure MOF, and the highest hydrogen production rate that the encapsulated exfoliated MoS2 could reach was 68.4 μmol h-1g-1, which was much higher than that of pure MOF. With a suitable band structure and improved light-harvesting ability, exfoliated MoS2@MOF could be a potential photocatalyst for hydrogen production.
关键词： hydrogen evolution,ZIF-8,exfoliation,MOF,MoS2,photocatalyst
更新于2025-09-23 15:22:29
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Photo-Induced Phase Transition of CdZnS Based Nanocomposite at Room Temperature Under Solar Irradiation
摘要： Photo-induced phase transition (PIPT) of CdZnS based nanocomposites that was performed at the room temperature under the solar light illumination is reported here for the first time. CdZnS particles were decorated on reduced graphene oxide (RGO) with a solvothermal process and consequently RGO-CdZnS-5%Pt nanocomposites (PC) have been synthesized as zinc blende (cubic) phase of CdZnS. Zinc blende structure (cubic) of CdZnS components of PC was turned to wurtzite (hexagonal) crystal structure with PIPT during the photocatalytic hydrogen evolution reaction. The band gap of the photocatalyst decreased from 2.42 to 2.19 eV and the hydrogen evolution rate increased from 37.3 to 184.0 μ mol h?1 due to the PIPT process.
关键词： Photo-induced phase transition,Hydrogen production,Metal chalcogenides,Photocatalyst
更新于2025-09-23 15:22:29