- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
The fabrication of a biomass carbon quantum dot-Bi <sub/>2</sub> WO <sub/>6</sub> hybrid photocatalyst with high performance for antibiotic degradation
摘要： A novel biomass carbon quantum dots@Bi2WO6 (BC-QDs@Bi2WO6) photocatalyst with uniform dispersivity was prepared via a dialysis-assisted hydrothermal process. Multiple techniques including HR-TEM, XPS, UV-Vis, PL, photocurrent analysis, and electrochemical impedance spectroscopy were employed to investigate the morphology and structures as well as the optical and electronic properties of the as-prepared samples. The photocatalytic activity of BC-QDs@Bi2WO6 was assessed by the degradation of antibiotics (tetracycline, ciprofloxacin, and gatifloxacin). The improved photocatalytic activity was attributed to the quantum effect of BC-QDs, which acted as the light harvesting center, electron reservoir, and reaction center for degrading the pollutants. Furthermore, a plausible mechanism for photocatalysis was put forward according to the ESR and quenching experiments. The present work can have significant advantages in the construction of biomass carbon-based photocatalysts in pollutant degradation and improved light utilization.
关键词： Bi2WO6,dialysis-assisted hydrothermal process,photocatalyst,biomass carbon quantum dots,antibiotic degradation
更新于2025-09-16 10:30:52
-
Lignite-derived carbon quantum dot/TiO <sub/>2</sub> heterostructure nanocomposites: photoinduced charge transfer properties and enhanced visible light photocatalytic activity
摘要： Here, we present a facile and green route to cleanly and efficiently utilize low-rank lignite to produce in high yields and in situ synthesize CQDs/TiO2 heterostructure nanocomposites. Unlike other CQDs, the lignite-derived CQDs exhibit obvious concentration-dependent red-shifted absorption, unusual aggregation-induced different color emissions and strong orange-red solid-state fluorescence. Through the optimization of the CQD loading proportion, the 2 wt% CQDs/TiO2 shows the optimal photocatalytic performance under visible light. We highlight the CQDs/TiO2 heterostructure nanocomposites by focusing on their dynamic photoinduced charge transfer properties triggered by the heterostructure interface and their application as a photocatalyst under visible light. Our detailed work about the transfer behavior of photoinduced charges in coal-derived carbon quantum dot/TiO2 heterostructure nanocomposites may shed light on the intrinsic reasons for CQD/semiconductor enhanced photocatalytic activity.
关键词： photoinduced charge transfer,heterostructure nanocomposites,visible light photocatalytic activity,lignite-derived carbon quantum dots,TiO2
更新于2025-09-16 10:30:52
-
Engineering carbon quantum dots for enhancing the broadband photoresponse in a silicon process-line compatible photodetector
摘要： Realization of heterojunction based broadband photodetectors (ultraviolet to near-infrared) compatible with existing silicon process technology has great promise for advanced optoelectronic applications. In this report, we demonstrate the application of carbon quantum dots (CQDs) synthesized from organic waste via a facile fabrication technique as a potential broadband photodetector in a hybrid (organic–inorganic) heterostructure with Si. The broadband photoresponse is further improved by impregnating the CQDs with reduced graphene oxide (rGO) and silver nanoparticles (AgNPs). The results show that the optimized incorporation of rGO aids in enhancing the photoresponse due to effective carrier transport, whereas AgNPs intensify the optical absorption due to localized surface plasmon resonance. The maximum responsivity and detectivity for the engineered CQDs are found to be around 1 A W?1 and 2 × 1012 Jones, respectively. This work demonstrates an economic, effective and feasible approach to harness natural resources for technological purposes, which can efficiently be adopted with presently available industry scale technologies.
关键词： silver nanoparticles,reduced graphene oxide,carbon quantum dots,silicon process technology,broadband photodetector
更新于2025-09-16 10:30:52
-
Synthesis and characterization of Mono-disperse Carbon Quantum Dots from Fennel Seeds: Photoluminescence analysis using Machine Learning
摘要： Herein, we present the synthesis of mono-dispersed c-QDs via single-step thermal decomposition process using the fennel seeds (Foeniculum vulgare). As synthesized c-QDs have excellent colloidal, photo-stability, environmental stability (pH) and do not require any additional surface passivation step to improve the fluorescence. The C-QDs show excellent PL activity and excitation-independent emission. Synthesis of excitation-independent c-QDs, to the best of our knowledge, using natural carbon source via pyrolysis process has never been achieved before. The effect of reaction time and temperature on pyrolysis provides insight into the synthesis of c-QDs. We used Machine-learning techniques (ML) such as pcA, McR-ALS, and nMf-ARD-So in order to provide a plausible explanation for the origin of the pL mechanism of as-synthesized c-QDs. ML techniques are capable of handling and analyzing the large pL data-set, and institutively recommend the best excitation wavelength for pL analysis. Mono-disperse c-QDs are highly desirable and have a range of potential applications in bio-sensing, cellular imaging, LeD, solar cell, supercapacitor, printing, and sensors.
关键词： Machine learning,Fennel seeds,Thermal decomposition,Photoluminescence,Carbon quantum dots
更新于2025-09-16 10:30:52
-
A simple and green synthesis of carbon quantum dots from coke for white light-emitting devices
摘要： Coke is a by-product of coal. This paper reports a simple and green chemical oxidation method for carbon quantum dots (CQDs) from coke for use in novel applications. The CQDs emit blue fluorescence and have a fluorescence quantum yield of 9.2% and blue-green-red spectral composition of 48%. A light-emitting diode (LED) was fabricated by combining the CQDs as a white-light converter with an ultraviolet chip. The Commission Internationale de L'Eclairage chromaticity coordinate (0.31, 0.35) and correlated color temperature (5125 K) of the LED are located in a cool white light zone, suggesting that they have superior potential application in lighting devices.
关键词： carbon quantum dots,white light-emitting devices,fluorescence,coke,chemical oxidation
更新于2025-09-16 10:30:52
-
Carbon quantum dots as a fluorophore for “inner filter effect” detection of metronidazole in pharmaceutical preparations
摘要： With houttuynia cordata as carbon source, photoluminescent carbon quantum dots (CDs) were obtained via a one-step hydrothermal procedure. The absorption band of metronidazole (MNZ, maximum absorption wavelength at 319 nm) can well overlap with the excitation bands of CDs (maximum excitation wavelength at 320 nm). A fluorescent approach has been developed for detection of MNZ based on the inner filter effect (IFE), in which as-prepared CDs act as an IFE fluorophore and the MNZ as an IFE absorber. We have investigated the mechanism of quenching the fluorescence of CDs and found that the IFE leads to an exponential decay in fluorescence intensity of CDs with increasing concentration of MNZ, but showed a good linear relationship (R2 ? 0.9930) between ln(F0/F) with the concentration of MNZ in the range of 3.3 (cid:2) 10(cid:3)6 to 2.4 (cid:2) 10(cid:3)4 mol L(cid:3)1. Due to the absence of surface modification of the CDs or establishing any covalent linking between the absorber (MNZ) and the fluorophore (CDs), the developed method is simple, rapid, low-cost and less time-consuming. Meanwhile, it possesses a higher sensitivity, wider linear range, and satisfactory selectivity and has potential application for detection of MNZ in pharmaceutical preparations.
关键词： metronidazole,carbon quantum dots,inner filter effect,pharmaceutical preparations,fluorescence detection
更新于2025-09-16 10:30:52
-
A novel optical fiber glucose biosensor based on carbon quantum dots-glucose oxidase/cellulose acetate complex sensitive film
摘要： A novel optical fiber glucose biosensor based on fluorescent carbon quantum dots (CQDs)-glucose oxidase (GOD)/cellulose acetate (CA) complex sensitive film was fabricated, in which the dip-coating method was adopted to immobilize the CQDs-GOD/CA complex sensitive film onto the end face of the optical fiber. The surface morphology, microstructure and optical performances of the sensitive film were characterized by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), Zeiss Axiovert 25 inverted microscope, Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible spectrophotometer and fluorescence spectrophotometer, respectively. The developed fiber-optic biosensor exhibits high sensitivity and repeatability for continuous online detection of low concentration glucose, allowing visualization of real-time glucose fluctuations over a period of time. The change ratios in fluorescence intensity of the biosensor are linear with glucose concentration in various ranges including micromole and nanomole levels, and the relationship between relative fluorescence intensity ratio and glucose concentration complies well with the modified Stern-Volmer equation in the range of 10-200 μmol/L with the detection limit of 6.43 μM, and in the range of 10-100 nmol/L with the detection limit of 25.79 nM, respectively.
关键词： Optical fiber,Carbon quantum dots-glucose oxidase/cellulose acetate complex sensitive film,Glucose sensing,Fluorescence quenching
更新于2025-09-16 10:30:52
-
Post-decorated surface fluorophores enhance the photoluminescence of carbon quantum dots
摘要： Photoluminescence (PL) is the center property to deploy carbon quantum dots (CQDs) in diverse applications although their physicochemical origin is still debated. Herein, carboxylic-terminated CQDs were synthesized from citric acid (CA) and treated sequentially with ethylenediamine (EDA). Infrared, magnetic, X-ray photoelectron and UV–Vis spectroscopies indicated the formation of surface fluorophores by the EDA treatment. The post-decorated surface fluorophores accounted for a resolved UV absorption band at 346 nm, which originated from HOMO → LUMO transition in the fluorophores. The post-decorated fluorophores dominated the emission spectrum of CQDs when excited with wavelengths below 340 nm and enhanced the PL quantum yield of CQDs from 20.7% to 47.6%. The results pave new understanding on the optical properties of CQDs derived from CA and amines.
关键词： Photoluminescence enhancement,Surface fluorophores,Optical origins,Amine treatment,Carbon quantum dots
更新于2025-09-16 10:30:52
-
Photoluminescence and Photodetecting Properties of the Hydrothermally Synthesized Nitrogen-Doped Carbon Quantum Dots
摘要： Carbon quantum dots (CQDs) have attracted more and more attention as the representative of a new generation of photoluminescence (PL) and photodetecting materials due to their unique optoelectrical properties. However, the formation mechanism of the CQDs as well as the origin of PL from the CQDs are still open questions to be issued. Here, we report our recent progress on the synthesis of the nitrogen-doped carbon quantum dots (N-CQDs) with a high photoluminescence quantum yield (PLQY) of 97.4% by adjusting the hydrothermal synthesis parameters with the citric acid (CA) and ethylenediamine (EDA) as the precursors. The detailed structure and properties indicate that N-CQDs is synthesized by dehydration, condensation, and carbonization, and the PL is attributed to the synergistic effect of the carbogenic core and the surface/molecule state. With above progress, an all-carbon-based ultra-violet (UV) photodetector is fabricated based on the N-CQDs/graphene hybrid composites, which exhibits significant negative photoconductivity phenomenon. A maximal negative responsivity up to 2.5×104 AW-1 at UV region has been observed, which was attributed to the two competing mechanisms. One is the oxygen adsorption and photo-desorption induced negative photoresponse, while the other is the surface defects in N-CQDs related positive photoconducting. Our work reveals the mechanisms driven force behind positive and the negative photoconducance phenomenon of photodetectors based on CQDs, which not only contributes to the further understanding of the fluorescent and photoresponse mechanisms of CQDs, and promotes the application potential of CQDs in the field of photodetection and nano-optoelectronic sensors.
关键词： Photodetecting,Nitrogen-doped,Hydrothermal synthesis,Photoluminescence,Carbon quantum dots
更新于2025-09-16 10:30:52
-
Enhanced photocatalytic degradation of antibiotics in water over functionalized N,S-doped carbon quantum dots embedded ZnO nanoflowers under sunlight irradiation
摘要： ZnO is widely used as a photocatalyst in industry, however, it is still a challenge to degrade refractory antibiotics in water. In this study, a novel surface-functionalized N,S-doped carbon quantum dot (N,S-CQD) was synthesized and embedded into ZnO for the formation of a new ZnO/N,S-CQDs hybrid nanoflower via one-pot hydrothermal process. The as-prepared ZnO/N,S-CQDs showed significantly enhanced photocatalytic activity under visible and near-infrared (NIR) light irradiation, in which 72.8% of MG was decomposed after 180 min under NIR light. In addition, approximately 92.9% and 85.8% of ciprofloxacin (CIP) were degraded by ZnO/N,S-CQDs under simulated sunlight for 20 min and natural sunlight for 50 min, respectively. Furthermore, the mechanism was investigated and the results show that the surface functionalization, electron transfer, up-converted luminescence properties of N,S-CQDs, together with the highly reactive facets of ZnO nanoflowers, made great contributions to the enhanced photocatalytic activity of ZnO/N,S-CQDs. Additionally, the results of active species trapping experiments indicated that the hydroxide free radicals, holes and superoxide radical anions all played certain roles in the photocatalytic reaction. Finally, ZnO/N,S-CQDs was employed for photodegradation of antibiotics in actual water, the degradation efficiency of antibiotics still remained above 60% after 120 min. We believe that the ZnO/N,S-CQDs nanoflower is a promising photocatalyst for the degradation of refractory antibiotics under sunlight irradiation. The relatively low cost and excellent photocatalytic performance of ZnO/N,S-CQDs is beneficial for industrial applications.
关键词： antibiotics,carbon quantum dots,ZnO nanoflowers,photocatalysis,sunlight irradiation
更新于2025-09-16 10:30:52