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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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In Situ Synthesis of Fluorescent Mesoporous Silica–Carbon Dot Nanohybrids Featuring Folate Receptor-Overexpressing Cancer Cell Targeting and Drug Delivery
摘要： Multifunctional nanocarrier-based theranostics is supposed to overcome some key problems in cancer treatment. In this work, a novel method for the preparation of a fluorescent mesoporous silica–carbon dot nanohybrid was developed. Carbon dots (CDs), from folic acid as the raw material, were prepared in situ and anchored on the surface of amino-modified mesoporous silica nanoparticles (MSNs–NH2) via a microwave-assisted solvothermal reaction. The as-prepared nanohybrid (designated MSNs–CDs) not only exhibited strong and stable yellow emission but also preserved the unique features of MSNs (e.g., mesoporous structure, large specific surface area, and good biocompatibility), demonstrating a potential capability for fluorescence imaging-guided drug delivery. More interestingly, the MSNs–CDs nanohybrid was able to selectively target folate receptor-overexpressing cancer cells (e.g., HeLa), indicating that folic acid still retained its function even after undergoing the solvothermal reaction. Benefited by these excellent properties, the fluorescent MSNs–CDs nanohybrid can be employed as a fluorescence-guided nanocarrier for the targeted delivery of anticancer drugs (e.g., doxorubicin), thereby enhancing chemotherapeutic efficacy and reducing side effects. Our studies may provide a facile strategy for the fabrication of multifunctional MSN-based theranostic platforms, which is beneficial in the diagnosis and therapy of cancers in future.
关键词： Targeted drug delivery,Fluorescence imaging,Mesoporous silica nanoparticles,Carbon dots,Chemotherapy
更新于2025-11-14 14:48:53
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Efficient visible light driven degradation of sulfamethazine and tetracycline by salicylic acid modified polymeric carbon nitride via charge transfer
摘要： Photocatalysis has been widely studied as a promising technique for removal of organic pollutants in wastewater. A modified carbon nitride has been designed for this purpose. In this study, a facile method to synthesize distorted carbon nitride by simply copolymerizing urea and salicylic acid (SA) has been explored. The incorporation of SA induced the structure change from planar structure to distorted curls structure. Compared to pristine CN, the CN-SA shows wide light absorption, which is attributed to the n → π* transition at the nitrogen atoms with lone pair electrons of heptazine units. The photoelectrode of CN-SA exhibited higher photocurrent and lower charge resistance than that of pristine CN electrode, indicating that the photogenerated charge carriers of CN-SA are more efficiently separated. As a result, the optimal CN-SA shows 2-fold enhancement in degradation of tetracycline (TC) as compared to pristine CN. Furthermore, we found that the degradation rate of sulfamethazine (SMZ) was 0.0823 min?1 using the CN-SA photocatalyst, which is three times higher than that of pristine CN (0.0293 min?1). In addition, the CN-SA shows good stability without structural change or loss of photocatalytic performance after four cycles. According to the radical species trapping experiments and electron spin resonance analyses, ?O2? and h+ were the main active species involved in the degradation of organic pollutants. The developed strategy provides a novel approach to design the tunable band structure of organic semiconductor materials for various applications.
关键词： Salicylic acid,Photocatalysis degradation,Carbon nitride,Charge separation,Antibiotics
更新于2025-11-14 14:48:53
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Gold doping induced strong enhancement of carbon quantum dots fluorescence and oxygen evolution reaction catalytic activity of amorphous cobalt hydroxide
摘要： Gold doping induced strong enhancement of carbon quantum dots fluorescence and oxygen evolution reaction catalytic activity of amorphous cobalt hydroxide. Water splitting using electrocatalysts is expected to provide an alternative green energy source to meet increasing energy demands as well as addressing environmental concerns related to fossil fuels. Herein, we report one-step synthesis of sulfur, nitrogen and Au-doped carbon quantum dots (Au-SCQDs) and strong enhancement of fluorescence intensity and oxygen evolution reaction (OER) catalytic activity of amorphous Co(OH)2 nanoparticles compared to pure Co(OH)2 as well as commercial RuO2 and Pt/C catalysts. Au doping into sulfur and nitrogen co-doped CQDs showed over seventy times enhanced fluorescence. OER studies of amorphous-Co(OH)2 incorporated Au-SCQDs produced current density of 178 mA cm?2 at the applied potential of 2.07 V whereas un-doped Co(OH)2 showed current density of 59 mA cm?2. To produce geometric current density of 10 mA cm?2, amorphous Co(OH)2-Au-SCQDs (CSA) required 388–456 mV overpotential depending on the Au ion concentration used for preparing the Au-SCQDs, which is equal to or lower than overpotential required by commercial electrocatalysts. The strongly enhanced OER activity of Co(OH)2-Au-SCQDs (CSA) was attributed to the presence of electronegative metallic conducting Au atoms along with the high catalytic surface area of amorphous Co(OH)2. The present studies demonstrate a new method of exploiting amorphous Co(OH)2NPs electrocatalysts that could provide more catalytically active sites by integrating an electronegative conducting Au atom doped SCQDs matrix.
关键词： amorphous cobalt hydroxide,fluorescence,water splitting,Gold doping,carbon quantum dots,oxygen evolution reaction,electrocatalysts
更新于2025-10-22 19:40:53
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Semiconducting carbon nanotubes in photovoltaic blends: The case of pTB7:PC <sub/>60</sub> BM:(6,5) SWNT
摘要： Blends of carbon nanotubes with conjugated polymer and fullerene derivatives are complex nanocomposite systems, which have recently attracted great research interest for their photovoltaic ability. Therefore, gaining a better understanding of the excitonic dynamics in such materials can be important to boost the efficiency of excitonic solar cells. Here, we studied the photophysics of a ternary system in which the polymer PTB7 and the fullerene derivative PCBM are integrated with (6,5) single walled carbon nanotubes. We highlight the contribution of SWNTs in the exciton dissociation and in the charge transfer process. These findings can be useful for the exploitation of these multi-component systems for organic photovoltaic and, in general, optoelectronic applications.
关键词： excitonic dynamics,PCBM,photovoltaic blends,PTB7,SWNTs,carbon nanotubes
更新于2025-10-22 19:40:53
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Ultra-selective fiber optic SPR platform for the sensing of dopamine in synthetic cerebrospinal fluid incorporating permselective nafion membrane and surface imprinted MWCNTs-PPy matrix
摘要： Surface plasmon resonance (SPR) based dopamine sensor is realized using the state-of-art technique of molecular imprinting over an optical fiber substrate. Polypyrrole (PPy) is depicted as an effective polymer for the imprinting of dopamine through a green synthesis approach. Sensitivity of the probe is enhanced by the augmenting effect of surface imprinting of dopamine in polypyrrole over multiwalled carbon nanotubes (MWCNTs). To ensure the permselectivity of the probe towards dopamine molecules, a cation exchange polymer, nafion, is utilized as a membrane over imprinted sites to reduce the interference from anionic analytes like ascorbic acid and uric acid at physiological pH. The probe is characterized for a wide range of dopamine concentration from 0 to 10-5 M in artificial cerebrospinal fluid. Various probe parameters are varied to maximize the sensitivity of the sensor. The sensor possesses 18.9 pM as the limit of detection (LOD) which is lowest of those reported in the literature. The manifestation of sensing probe over an optical fiber along with the improved LOD makes the approach highly advantageous in terms of stability, repeatability, online remote monitoring, fast response, and miniaturization for its in vivo/in vitro applications in clinical sensing of dopamine.
关键词： surface plasmon,dopamine,Optical fiber,polypyrrole,nafion,molecular imprinting,sensor,multiwalled carbon nanotube
更新于2025-10-22 19:40:53
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Carbon Allotropes: Metal-Complex Chemistry, Properties and Applications || Classic Carbon Nanostructures
摘要： The era of carbon-based nanotechnology, as it is well-known, started from 1985 when the fullerene C60 was discovered. The rediscovery of carbon nanotubes and unexpected discovery of graphene gave a powerful impulse to the further development of carbon nanostructures. At present, these nanocarbons, as well as nanodiamonds or nanofibers, can already be considered as 'conventional' carbon nanostructures.
关键词： nanofibers,nanodiamonds,carbon nanotubes,graphene,carbon nanostructures,fullerenes
更新于2025-09-23 15:23:52
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Visible light photocatalytic mineralization of bisphenol A by carbon and oxygen dual-doped graphitic carbon nitride
摘要： A facile thermal polymerization was applied to synthesize carbon and oxygen dual-doped graphitic carbon nitride (MACN) with controllable electronic band structure using malonic acid and urea as precursors. The C and O atoms substituted the sp2 N atom in graphitic carbon nitride (CN). The 1MACN (1 represented that the weight ratio of malonic acid to urea is 1% during the synthesis) with optimal band structure could decompose 15 ppm bisphenol A (BPA) within 150 min, and the mineralization rate reached to 52%. The superior photocatalytic performance of 1MACN was mainly ascribed to electronic band structure together with optical properties. On the one hand, the formation of delocalized big p bonds favored the electrons transfer after the introducing of carbon atoms. On the other hand, a positive charge density existed on the C atoms because of high electronegativity of contiguous O (3.44) that substituted N compared with C (2.55), which could attribute to high activity of MACN catalyst. The study will contribute to the further improvement of visible-light photocatalytic BPA degradation and mineralization.
关键词： BPA mineralization,Carbon-oxygen dual-doping,Visible-light photocatalytic,Graphitic carbon nitride
更新于2025-09-23 15:23:52
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Artificial Photosynthesis for Carbon Dioxide Reduction and Conversion
摘要： In recent years, solar fuel or chemical production based on the photoreduction or fixation of CO2, the so-called “artificial photosynthesis” has received considerable attention. Thus, the development of an effective catalyst for the conversion of CO2 to useful organic molecules is desirable. Biocatalysts for CO2 reduction and conversion are useful catalyst for the artificial photosynthesis system. In this review, two types of artificial photosynthesis systems for CO2 reduction and conversion consisting of the visible-light sensitizer and biocatalyst are introduced. One is the artificial photosynthesis with visible-light sensitizer and biocatalyst for CO2 photoreduction to formic acid or methanol. The other one is the artificial photosynthesis with visible-light sensitizer, and novel electron carrier molecule and biocatalyst for the carbon-carbon bond formation from CO2 as a feedstock.
关键词： carbon-carbon bond formation,artificial photosynthesis,biocatalyst,CO2 reduction and conversion
更新于2025-09-23 15:23:52
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CePd‐Nanoparticles‐Incorporated Carbon Nanofibers as Efficient Counter Electrode for DSSCs
摘要： In this study, the cerium-palladium (CePd) incorporated carbon nanofibers (CNFs) were manufactured by low-cost and versatile electrospinning technique and successfully applied as a counter electrode to fabricate the dye-sensitized solar cells (DSSCs). The utilized physiochemical techniques, X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscope (FESEM), and transmission electron microscope (TEM) confirmed the formation of carbon nanofibers (CNFs) incorporated by Ce and Pd nanoparticles. CePd incorporated CNFs were preliminary presented good electrocatalytic activity towards the iodide redox couple, as investigated by cyclic voltammetry. The DSSC fabricated using CePd incorporated CNFs based counter electrode (CE) attained an applicable power conversion efficiency (PCE) of 4.52% along with open circuit voltage (VOC) of 0.739 V, a short-circuit current density (JSC) of 11.42 mA/cm2 and fill factor (FF) of 0.54. According to primary results, the CePd incorporated CNFs based CE is a promising, and cost-effective alternative CE for photoelectrochemical devices.
关键词： Alloys nanoparticles,Solar cells,Electrocatalyst,Cyclic voltammetry,Carbon nanofibers
更新于2025-09-23 15:23:52