Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)is a highly successful conductive polymer utilized as an electrode material in energy storage units for portable and wearable electronic de-vices.Neve...Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)is a highly successful conductive polymer utilized as an electrode material in energy storage units for portable and wearable electronic de-vices.Nevertheless,employing PEDOT:PSS in supercapacitors(SC)in its pristine state presents challenges due to its suboptimal electrochemical performance and operational instability.To surmount these limita-tions,PEDOT:PSS has been integrated with carbon-based materials to form flexible electrodes,which ex-hibit physical and chemical stability during SC operation.We developed a streamlined fabrication process for high-performance SC electrodes composed of PEDOT:PSS and carbon quantum dots(CQDs).The CQDs were synthesized under microwave irradiation,yielding green-and red-light emissions.Through optimiz-ing the ratios of CQDs to PEDOT:PSS,the SC electrodes were prepared using a spray-coating technique,marking a significant improvement in device performance with a high volumetric capacitance(104.10 F cm-3),impressive energy density(19.68 Wh cm^(-3)),and excellent cyclic stability,retaining~85% of its original volumetric capacitance after 15,000 repeated GCD cycles.Moreover,the SCs,when utilized as a flexible substrate,demonstrated the ability to maintain up to~85% of their electrochemical performance even after 3,000 bending cycles(at a bending angle of 60°).These attributes render this hybrid composite an ideal candidate for a lightweight smart energy storage component in portable and wearable electronic technologies.展开更多
Carbon quantum dots are a new type of fluorescent nanomaterials with broad applications in drug delivery,bioimaging,solar cells,and photocatalysis due to their unique biocompatibility,optical properties and easy funct...Carbon quantum dots are a new type of fluorescent nanomaterials with broad applications in drug delivery,bioimaging,solar cells,and photocatalysis due to their unique biocompatibility,optical properties and easy functionalization.In the meantime,because of its high carbon content,renewable nature,and environmental friendliness,lignin has drawn the attention of researchers as a desirable raw material for creating carbon quantum dots.Here we review the synthesis of carbon quantum dots from lignin,focusing on synthetic methods,properties,and applications in energy,and photocatalysis.Later,we propose some new development prospects from preparation methods,luminescence mechanism research,application,and commercial cost of lignin carbon quantum dots.Finally,based on this,the development prospects of this field are prospected and summarized.展开更多
Devising robust S-scheme photocatalysts is of central importance for achieving high-efficient micropollu-tant decontamination.However,the conscious optimization of S-scheme system with high performance remains a prime...Devising robust S-scheme photocatalysts is of central importance for achieving high-efficient micropollu-tant decontamination.However,the conscious optimization of S-scheme system with high performance remains a prime challenge.Herein,carbon quantum dots(CDs)and Mn_(0.5)Cd_(0.5)S(MCS)are mounted on BiOBr(BOB)microspheres,establishing an advanced S-scheme heterojunction with interfacial Bi-S bond.The interfacial Bi-S bonds function as superb channels at atomic-scale to abate the energy barrier for S-scheme charge transportation.Meanwhile,CDs serve as electron collectors to preserve highly reductive electrons from MCS,further augmenting the spatial separation of photo-carriers.Therefore,the optimized CDs/MCS/BOB(MBC)heterojunction manifests significantly strengthened tetracycline hydrochloride(TC)destruction activity and its reaction rate constant is approximately 3.1,2.2,2.1,and 1.5 folds that than that of MCS,BOB,BOB/CDs and MCS/BOB.In addition,MBC exhibits high stability and significant resistance to environmental interferences.The toxicology evaluation confirms the effective abatement of toxicity of TC after treatment.This achievement demonstrates the benefits of CDs-optimized S-scheme photosystems with chemical bonds for photocatalytic water decontamination.展开更多
The endocrine-disrupting chemicals(EDCs)and antibiotics are causing negative effects on human beings and animals by disrupting the endocrine system and spreading antimicrobial resistance.The current need is to eradica...The endocrine-disrupting chemicals(EDCs)and antibiotics are causing negative effects on human beings and animals by disrupting the endocrine system and spreading antimicrobial resistance.The current need is to eradicate pharmaceutical waste from water bodies using advanced catalytic systems with high efficiency.Novel ternary carbon quantum dots(CQDs)decorated Z-Scheme WS_(2)-PANI nanocomposite was prepared by a green synthesis assisted in-situ polymerization for the photodegradation and detection of Estradiol(EST)and Nitrofurantoin(NFT).HRTEM micrographs revealed the formation of CQDs with a mean size of 4nm anchored on the surface of WS_(2)/PANI(width:PANI~20-30nm).The ternary nanocomposite showed excellent photocatalytic activity,degraded NFT(95.7%in 60min),and EST(96.6%in 60min).The rate kinetics study confirms the reaction followed pseudo first-order model.This heterostructure exhibited enhanced performances by modulating the energy level configuration,enhancing the absorption of visible light(2.4eV),and significantly improving the charge separation,three times higher than pristine WS_(2).These are highly favorable for increasing the generation of photoinduced charges and enhancing the overall performance of the catalyst.Further,the electrochemical sensor was prepared using CQDs@WS_(2)/PANI nanocomposite on a paper-based electrode.The CQDs@WS_(2)/PANI exhibit a linear response of 0.1-100nM,with a limit of detection of 13nM.This synergistic interfacial interaction resulted in the significantly improved electrochemical performance of the modified electrode.The proposed Z-scheme was justified by electron paramagnetic resonance(EPR)and scavenger experiment.An intermediate degradation pathway was also proposed.The synthesized materials were characterized using FESEM,HRTEM,XRD,FTIR,XPS,UV-visible spectroscopy,PL,and TRPL.Therefore,this study provides a direct approach to fabricate a heterojunction that combines two-dimensional,one dimensional,and zero-dimensional properties,enabling control over the energy level configuration and subsequent improvements in photocatalytic and electrocatalytic efficiency.展开更多
Precise control of luminescence in carbon quantum dots(CQDs),from single-color to full-color emission,is crucial for advancing their applications in biomedical imaging and display technologies.While CQDs luminescence ...Precise control of luminescence in carbon quantum dots(CQDs),from single-color to full-color emission,is crucial for advancing their applications in biomedical imaging and display technologies.While CQDs luminescence is primarily influenced by conjugated domains and surface states,the underlying interaction mechanisms remain poorly understood.This study explores a graded nitro-engineering approach to simultaneously regulate surface states and sp^(2)conjugated domains through nitro(-NO_(2))modulation,enabling comprehensive color tuning.Using o-phenylenediamine(o-PD)as the carbon source and adjusting nitric acid(HNO_(3))concentrations,we synthesized tricolor-emitting nitro-functionalized CQDs(NO_(2)-CQDs).At lower-NO_(2) concentrations,luminescence is mainly influenced by surface states,where the electron-withdrawing effect of-NO_(2) enhancesπ-electron delocalization and stabilizes sp^(2)conjugation.With increasing-NO_(2) content,the lowest unoccupied molecular orbital(LUMO)energy level decreases(-2.12 eV to-3.39 eV),resulting in a red-shift in fluorescence.At higher-NO_(2) concentrations,luminescence is primarily affected by the sp^(2)conjugated domain,where steric hindrance reduces molecular planarity and conjugation,leading to a blue-shift in fluorescence as the sp^(2)domain size decreases(4.03 nm to 2.83 nm).Combining experimental results with density functional theory(DFT)calculations,we reveal the dual role of-NO2in modulating CQDs luminescence,an approach rarely achieved through surface functionalization.This work presents a novel strategy for precise tuning of CQDs luminescence across the visible spectrum.展开更多
The growing environmental concerns regarding rare earth elements in fluorescent powders,along with high production costs,have increased the demand for sustainable alternatives.We propose a promising solution using lum...The growing environmental concerns regarding rare earth elements in fluorescent powders,along with high production costs,have increased the demand for sustainable alternatives.We propose a promising solution using luminescent metal-organic frameworks(LMOFs)with large surface areas and tunable pore structures,combined with organic carbon quantum dots(CQDs).This study develops a novel white lightemitting diode(WLED)fluorescent powder by incorporating yellow-fluorescent quantum dots(CQDs-Y)into blue-emitting LMOF(ZJU-28),forming the composite material CQDs-Y-n@ZJU-28.The composite exhibits excellent thermal and chemical stability,long-term storage performance,and emits warm white light(CIE:0.3277,0.3281)when subjected to excitation at 365 nm,along with an external quantum efficiency(EQE)of 8.85%.Furthermore,it exhibits tunable emission characteristics and promising LED performance,showcasing a color rendering index(CRI)of 78 and a correlated color temperature of 3384 K.The emitted light undergoes minimal deviation in color towards the white end of the spectrum in the temperature range of 277-437 K,making it an ideal candidate for advanced WLED applications.展开更多
The authors regret to report some missing information in the synthetic reagents and associated changes of the paper.On page 511,the author information reads:“5.0 mmol of citric acid(C_(6)H_(8)O_(7)),5.0 mmol of ferri...The authors regret to report some missing information in the synthetic reagents and associated changes of the paper.On page 511,the author information reads:“5.0 mmol of citric acid(C_(6)H_(8)O_(7)),5.0 mmol of ferric chloride hexahydrate(FeCl_(3)·6H_(2)O),and 10.0 mmol of o-phenylenediamine(C_(6)H_(8)N_(2))were combined with 40 mL of deionized water and magnetically stirred until fully dissolved.”展开更多
Hydrogels are widely used in reservoir flow control to enhanced oil recovery.However,challenges such as environmental contamination from conventional crosslinkers,poor solubility of crosslinking agents,and short gelat...Hydrogels are widely used in reservoir flow control to enhanced oil recovery.However,challenges such as environmental contamination from conventional crosslinkers,poor solubility of crosslinking agents,and short gelation times under high-temperature conditions(e.g.,150℃)have hindered their practical application.Herein,we present the synthesis of amine-functionalized carbon quantum dots(NH_(2)-CQDs),which act as both a nano-crosslinker and a nano-reinforcing agent within hydrogel systems.The NH_(2)-CQDs-incorporated hydrogel can remain stability for 300 days under the conditions of a mineralization degree of 2.11×10^(4)mg/mL and 170℃,and has high tensile strength(371 kPa),good toughness(49.6 kJ/m~3),excellent viscoelasticity(G'=960 Pa,G"=460 Pa)and shear resistance.In addition,NH_(2)-CQDs adds many hydroxyl groups to the hydrogel,which can be attached to the surface of various substances.At the same time,micro-nano capsules containing NH_(2)-CQDs were formed by self-assembly of hydrophobic SiO_(2)on water droplets,the NH_(2)-CQDs solution is encapsulated in a capsule,and when stimulated by external conditions(temperature,pH,surfactant),the capsule releases the NH_(2)-CQDs solution,this method greatly delays the crosslinking time between polymer and crosslinker at high temperature.Under the condition of 170℃and pH=7,the gelation time of 10%hydrophobic SiO_(2)coated hydrogel is 44 times that of uncoated hydrogel,which can be effectively used for deep formation flow control,and CQD give hydrogels fluorescence properties that can be used for underground signal tracking.展开更多
Corn stover,an agricultural waste,was used to prepare nitrogen self-doped carbon quantum dots(CQDs)through a simple hydrothermal method with only water at near room temperature for the first time.The surface,electroch...Corn stover,an agricultural waste,was used to prepare nitrogen self-doped carbon quantum dots(CQDs)through a simple hydrothermal method with only water at near room temperature for the first time.The surface,electrochemical,and photovoltaic characteristics of CQDs doped TiO_(2)in dye-sensitized solar cells(DSSCs)were thoroughly and systematically examined.The average diameter of blue-fluorescence CQDs measured by a high-resolution transmission electron microscope(HR-TEM)was 4.63±0.87 nm,which consisted of polar functional groups.The highest occupied molecular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)energy of the biomass-derived CQDs,determined by the cyclic voltammetry(CV)test,were,−5.48 eV and−3.89 eV,respectively.The negative shift of flat band potential(Vfb)in CQDs incorporated photoanode implies the fermi level shifted upward.Experimental results revealed that the improved performance of DSSCs was due to charge transport enhancement and separation,which resulted in the improved energy level configuration between TiO_(2),CQDs,and electrolytes.In this regard,the CQDs serve as a mediator that enables charge carrier transport without hindrance.In this study,CQDs added to TiO_(2)+N719,increased short circuit current density(JSC)and power conversion efficiency(PCE)value by∼26.00%(10.13 to 12.69 mA/cm^(2))and 27.20%(4.78%to 6.08%),respectively.展开更多
Balancing the adsorption of OH⁻and 5-hydroxymethylfurfural(HMF)is crucial in optimizing the competing HMF oxidation reaction and oxygen evolution reaction,especially given the polymerization tendency of HMF in alkalin...Balancing the adsorption of OH⁻and 5-hydroxymethylfurfural(HMF)is crucial in optimizing the competing HMF oxidation reaction and oxygen evolution reaction,especially given the polymerization tendency of HMF in alkaline solutions.Herein,we present an innovative approach for rapidly synthesizing a NiFe bimetallic metalorganic framework(MOF)induced by electron-withdrawing carbon quantum dot(EW-CQD)via electron beam irradiation within 2 min.EW-CQD serve as structural regulators,expanding the NiFe-MOF interlayer spacing,increasing reactive site availability,and more effectively balancing the adsorption of OH6(-) and HMF,thereby significantly boosting the oxidation activity of HMF.The resulting EW-CQD-MOF exhibits a low potential of 1.36 V vs.RHE at 10 mA cm^(-2)and maintains excellent durability over 120 h.Comprehensive in situ characterization elucidates the HMF oxidation reaction pathway,showing high selectivity towards 2,5-furandicarboxylic acid(FDCA)under ambient conditions,with an impressive HMF conversion rate of 94%and FDCA selectivity of 96%within 6 h.These findings underscore the critical role of structural optimization and adsorption balance in catalytic performance enhancement and offer valuable insights for designing high-efficiency catalysts,advancing sustainable catalytic processes.展开更多
Hydrogen evolution reaction(HER)in acidic media has been spotlighted for hydrogen production since it is a favourable kinetics with the supplied protons from a counterpart compared to that within alkaline environment....Hydrogen evolution reaction(HER)in acidic media has been spotlighted for hydrogen production since it is a favourable kinetics with the supplied protons from a counterpart compared to that within alkaline environment.However,there is no choice but to use a platinum-based catalyst yet.As for a noble metal-free electrocatalyst,incorporation of earth-abundant transition metal(TM)atoms into nanocarbon platforms has been extensively adopted.Although a data-driven methodology facilitates the rational design of TM-anchored carbon catalysts,its practical application suffers from either a simplified theoretical model or the prohibitive cost and complexity of experimental data generation.Herein,an effective and facile catalyst design strategy is proposed based on machine learning(ML)and its model verification using electrochemical methods accompanied by density functional theory simulations.Based on a Bayesian genetic algorithm ML model,the Ni-incorporated carbon quantum dots(Ni@CQD)loaded on a three-dimensional reduced graphene oxide conductor are proposed as the best HER catalyst amongst the various TM-incorporated CQDs under the optimal conditions of catalyst loading,electrode type,and temperature and pH of electrolyte.The ML results are validated with electrochemical experiments,where the Ni@CQD catalyst exhibited superior HER activity,requiring an overpotential of 151 mV to achieve 10 mAcm^(−2) with a Tafel slope of 52 mV dec^(−1) and impressive durability in acidic media up to 100 h.This methodology can provide an effective route for the rational design of highly active electrocatalysts for commercial applications.展开更多
Carbon quantum dots(CQDs)have re-ceived increasing interest owing to their excellent optical and chemical characteristics,and high biocompatibil-ity.Herein,turmeric was employed as a carbon source to fabricate green C...Carbon quantum dots(CQDs)have re-ceived increasing interest owing to their excellent optical and chemical characteristics,and high biocompatibil-ity.Herein,turmeric was employed as a carbon source to fabricate green CQDs(named WT-JHCQDs)by hydrother-mal technique.The fluorescence of WT-JHCQDs is particularly stable at differ-ent pH and high concentrations of NaCl.Moreover,WT-JHCQDs exhibit low cytotoxicity,good antioxidant properties,and outstanding biocompatibility.The WT-JHCQDs possess protruding ability of cell imaging and bacteria imaging.This work provides a promising strat-egy for designing excellent fluorescent probes for bioimaging.展开更多
Nitrogen-doped carbon quantum dots(N-CQDs),synthesized via the rapid pyrolysis of ammonium citrate dibasic and ethylenediamine dihydrochloride,demonstrate remarkable chemiluminescence capabilities,emitting a vibrant b...Nitrogen-doped carbon quantum dots(N-CQDs),synthesized via the rapid pyrolysis of ammonium citrate dibasic and ethylenediamine dihydrochloride,demonstrate remarkable chemiluminescence capabilities,emitting a vibrant blue-green light in peroxyoxalate chemiluminescence(PO-CL)reactions.Among these,a distinct variant of N-CQDs is an exceptionally sensitive biosensor,facilitating the swift detection of copper ions(Cu^(2+))within human plasma and urine samples.Upon rapid binding of N-CQDs and Cu^(2+),non-emissive complex forms due to intra-chemiluminescence resonance energy transfer(intra-CRET)initiated by the PO-CL reaction.Consequently,the brightness of the biosensor diminishes proportionally with increasing Cu^(2+)concentrations in human samples.Featuring a low sensing limit of 19.5 nM and an expansive dynamic range spanning from 0.05 to 3.8μM,this biosensor empowers the rapid and precise quantification of trace Cu^(2+)levels with exceptional accuracy and recovery rates.In alignment with copper quantification guidelines set forth by the Environmental Protection Agency(EPA)and the National Institutes of Health(NIH),this selective biosensor stands as a cutting-edge monitoring tool,poised to advance analytical capabilities in various fields.展开更多
Zero-dimensional(0D)carbon quantum dots(CQDs),as a nanocarbon material in the carbon family,have garnered increasing attention in recent years due to their outstanding features of low cost,nontoxicity,large surface ar...Zero-dimensional(0D)carbon quantum dots(CQDs),as a nanocarbon material in the carbon family,have garnered increasing attention in recent years due to their outstanding features of low cost,nontoxicity,large surface area,high electrical conductivity,and rich surface functional groups.By virtue of their rapid electron transfer and large surface area,CQDs also emerge as promising functional materials for the applications in energy-conversion sectors through electrocatalysis.Besides,the rich functional groups on the surface of CQDs offer abundant anchoring sites and active sites for the engineering of multicomponent and high-performance composite materials.More importantly,the heteroatom in the CQDs could effectively tailor the charge distribution to promote the electron transfer via internal interactions,which is crucial to the enhancement of electrocatalytic performance.Herein,an overview about recent progress in preparing CQDs-based composites and employing them as promising electrode materials to promote the catalytic activity and stability for electrocatalysis is provided.The introduced CQDs could enhance the conductivity,modify the morphology and crystal phase,optimize the electronic structure,and provide more active centers and defect sites of composites.After establishing a deep understanding of the relationship between CQDs and electrocatalytic performances,the issues and challenges for the development of CQDs-based composites are discussed.展开更多
The development of large-scale synthetic methods for high quality carbon quantum dots(CQDs) is fundamental to their applications.However,the macroscopic preparation and scale up synthetic of CQDs is still in its infan...The development of large-scale synthetic methods for high quality carbon quantum dots(CQDs) is fundamental to their applications.However,the macroscopic preparation and scale up synthetic of CQDs is still in its infancy.Here,we report a facile,green,kilogram-scale synthesis of high quality fluorescent CQDs derived from poplar leaves via a one-step hydrothermal method.Notably,the throughput of CQDs can reach a level up to as high as 1.4975 kg in one pot.The structure and properties of the as-prepared CQDs were assessed through TEM,XRD,XPS and various spectroscopic methods.The obtained high quality CQD s with a photoluminescent quantum yield of 10.64% showed remarkable stability in aqueous media,rich functional groups,high photostability,consistent photoluminescence within biological pH range and low cytotoxicity.On account of these good properties,we demonstrated the multifunctional application to electrocatalytic water splitting,Fe^3+ sensing and bioimaging.It showed remarkable electrocatalytic activity,Fe^3+ sensitivity and good biocompatibility.This study provides a green,facile,inexpensive and large-scale method for producing high quality CQDs,which provides application value for large-scale production of CQDs.展开更多
Carbon quantum dots(CQDs)as a new class of emerging materials have gradually drawn researchers’concern in recent years.In this work,the graphitic CQDs are prepared through a scalable approach,achieving a high yield w...Carbon quantum dots(CQDs)as a new class of emerging materials have gradually drawn researchers’concern in recent years.In this work,the graphitic CQDs are prepared through a scalable approach,achieving a high yield with more than 50%.The obtained CQDs are further used as structure-directing and conductive agents to synthesize novel N,S-CQDs/NiCo2S4 composite cathode materials,manifesting the enhanced electrochemical properties resulted from the synergistic effect of highly conductive N,S-codoped CQDs offering fast electronic transport and unique micro-/nanostructured NiCo2S4 microspheres with Faradaic redox characteristic contributing large capacity.Moreover,the nitrogen-doped reduced graphene oxide(N-rGO)/Fe2O3 composite anode materials exhibit ultrahigh specific capacity as well as significantly improved rate property and cycle performance originating from the high-capacity prism-like Fe2O3 hexahedrons tightly wrapped by highly conductive N-rGO.A novel alkaline aqueous battery assembled by these materials displays a specific energy(50.2 Wh kg^−1),ultrahigh specific power(9.7 kW kg^−1)and excellent cycling performance with 91.5%of capacity retention at 3 A g^−1 for 5000 cycles.The present research offers a valuable guidance for the exploitation of advanced energy storage devices by the rational design and selection of battery/capacitive composite materials.展开更多
As a new member of carbon material family, carbon quantum dots (CQDs) have attracted tremendous attentions for their potentials in the heterogeneous photocatalysis applications. Due to the unique microstructure and op...As a new member of carbon material family, carbon quantum dots (CQDs) have attracted tremendous attentions for their potentials in the heterogeneous photocatalysis applications. Due to the unique microstructure and optical properties, the roles of CQDs played in the CQDs-based photocatalytic systems have been found to be diverse with the continuous researches in this regard. Herein, we provide a concise minireview to elaborate the multifarious roles of CQDs in photocatalysis, including photoelectron mediator and acceptor, photosensitizer, photocatalyst, reducing agent for metal salt, enhancing adsorption capacity and spectral converter. In addition, the perspectives on future research trends and challenges are proposed, which are anticipated to stimulate further research into this promising field on designing a variety of efficient CQDs-based photocatalysts for solar energy conversion. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B. V. and Science Press. All rights reserved.展开更多
Development of efficient heterostructured photocatalysts that respond to visible light remains a considerable challenge.We herein show the synthesis of ZnIn2S4/carbon quantum dot hybrid photocatalysts with flowerlike ...Development of efficient heterostructured photocatalysts that respond to visible light remains a considerable challenge.We herein show the synthesis of ZnIn2S4/carbon quantum dot hybrid photocatalysts with flowerlike microspheres via a facile solvothermal method.The ZnIn2S4/carbon quantum dot flowerlike microspheres display enhanced photocatalytic and photoelectrochemical activity compared with that of pure ZnIn2S4.With a content of only 0.5 wt%carbon quantum dots,93%of Cr(VI)is reduced under visible‐light irradiation at 40 min.As a co‐catalyst,the carbon quantum dots improve the light absorption and lengthen the lifetime of charge carriers,consequently enhancing the photocatalytic and photoelectrochemical activity.展开更多
A novel carbon quantum dots modified potassium titanate nanotubes(CQDs/K2 Ti6 O13)composite photocatalyst was synthesized by hydrothermal treatment combined with calcination.X-ray diffraction(XRD)pattern and transmiss...A novel carbon quantum dots modified potassium titanate nanotubes(CQDs/K2 Ti6 O13)composite photocatalyst was synthesized by hydrothermal treatment combined with calcination.X-ray diffraction(XRD)pattern and transmission electron microscopy(TEM)indicated formation of potassium titanate nanotubes and successful deposition of CQDs onto K2 Ti6 O13.The photocatalytic performance of CQDs/K2 Ti6 O13 composite was evaluated by degradation of amoxicillin(AMX)under the irradiation of visible light and lights with the wavelengths of 365,385,420,450,485,520,595 and 630 nm.The results showed that the photocatalytic activity of CQDs/K2 Ti6 O13 hybrid material was greatly enhanced compared with the neat K2 Ti6 O13 calcined at 300℃.The narrowed band gap energy(Eg)and transfer of photo-excited electron by CQDs inhibited the immediate combination of electron-hole pairs,thus promoting photocatalytic activity.Moreover,CQ,Ds/K2 Ti6 O13 exhibited a broad spectrum of photocatalytic ability and it was interesting that the photocatalytic activity decreased with the increase of the irradiation wavelength.Reactive oxygen species(ROS)quenching tests suggested the hole(h^+)and hydroxyl radical(^·OH)played the primary roles in photocatalytic degradation of AMX.Moreover,CQ.Ds/K2 Ti6 O13 showed good reusability for AMX photocatalytic degradation after five successive runs.This study proposed an available method for titanate nanomaterials modification,and the developed novel CQDs/K2 Ti6 O13hyb rid material is p ro mising fo r potential application on antibiotics removal fro m water and wastewater.展开更多
Carbon quantum dots(CQDs)are emerging as the new-generation light absorber for solar energy conversion.However,the low photosensitization efficiency of CQDs is one of the current bottlenecks impeding their large-scale...Carbon quantum dots(CQDs)are emerging as the new-generation light absorber for solar energy conversion.However,the low photosensitization efficiency of CQDs is one of the current bottlenecks impeding their large-scale practical applications in photocatalysis.Therefore,developing a facile approach for the engineering and functionalization of CQDs-based composites to improve the photosensitization efficiency of CQDs is highly desirable.On account of the abundant functional groups,especially oxygen-containing functional groups such as carbonyl,carboxyl,and hydroxyl present on their surface,CQDs can be readily combined with various organic molecules or polymers as a surface passivation component to reduce the nonradioactive surface recombination of photo-generated charge carriers,thus enabling the CQDs to exhibit strong photoluminescence in the visible and near-infrared spectral regions.Consequently,polymer passivation has been demonstrated as an ideal strategy to make it accessible for improving the sensitization efficiency of CQDs in photocatalytic applications.Branched polyethylenimine(BPEI)is one of polymers that contains a high density of amine groups and exhibits high electron mobility,which can be used as an electron injection material at the interface of nanomaterials.Besides,the BPEI polymer with amino groups exhibiting positive charge has been utilized for designing heterogeneous catalysts by an electrostatic self-assembly strategy.Therefore,BPEI is expected to modify the surface of inorganic oxides semiconductor to enhance the photosensitization efficiency of CQDs under visible light.However,to date,the study in this regard has been still unavailable In this work,we developed a facile approach to engineer well-distributed CQDs via electrostatic interaction on BPEI passivated TiO2 composites(BTC)as photocatalysts.The BTC composites with an optimal loading of 5%(w,mass fraction)CQDs outperformed the TiO2/CQDs(TC)composite and referential BPEI/SiO2/CQDs(BSC)composites for the photoreduction of 4-nitroaniline under visible light irradiation.The structure of the fabricated BTC composites was systematically investigated by the combined use of structural and spectral characterizations,demonstrating that the photosensitizer CQDs contacted well with the BPEI modified TiO2 nanoparticles.The comparison characterizations revealed that BPEI facilitated the dissociation and transfer of excitons as an electron transfer channel.The as-prepared BTC composites benefited from the favorable interfacial contact and effective transfer of photo-generated charge carriers,and thus manifested superior photocatalytic activity to the TC composite.It is expected that this strategy would be extended to other wide band gap semiconductor photocatalyst systems and open up new possibilities in designing efficient CQDs-based semiconductor artificial light harvesting systems by interfacial optimization.展开更多
基金supported by the National Research Foundation of Korea(NRF)through a grant provided by the Korean government(No.NRF-2021R1F1A1063451).
文摘Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)is a highly successful conductive polymer utilized as an electrode material in energy storage units for portable and wearable electronic de-vices.Nevertheless,employing PEDOT:PSS in supercapacitors(SC)in its pristine state presents challenges due to its suboptimal electrochemical performance and operational instability.To surmount these limita-tions,PEDOT:PSS has been integrated with carbon-based materials to form flexible electrodes,which ex-hibit physical and chemical stability during SC operation.We developed a streamlined fabrication process for high-performance SC electrodes composed of PEDOT:PSS and carbon quantum dots(CQDs).The CQDs were synthesized under microwave irradiation,yielding green-and red-light emissions.Through optimiz-ing the ratios of CQDs to PEDOT:PSS,the SC electrodes were prepared using a spray-coating technique,marking a significant improvement in device performance with a high volumetric capacitance(104.10 F cm-3),impressive energy density(19.68 Wh cm^(-3)),and excellent cyclic stability,retaining~85% of its original volumetric capacitance after 15,000 repeated GCD cycles.Moreover,the SCs,when utilized as a flexible substrate,demonstrated the ability to maintain up to~85% of their electrochemical performance even after 3,000 bending cycles(at a bending angle of 60°).These attributes render this hybrid composite an ideal candidate for a lightweight smart energy storage component in portable and wearable electronic technologies.
基金Sponsorship Program by CAST(2023QNRC001)University-Industry Collaborative Education Program(220901115200913,220901115201954)+2 种基金Hunan Provincial Natural Science Foundation of China(2022JJ40007)Jiangsu Agricultural Science and Technology Innovation Fund(CX(22)3047)the National Natural Science Foundation of China(32201491)。
文摘Carbon quantum dots are a new type of fluorescent nanomaterials with broad applications in drug delivery,bioimaging,solar cells,and photocatalysis due to their unique biocompatibility,optical properties and easy functionalization.In the meantime,because of its high carbon content,renewable nature,and environmental friendliness,lignin has drawn the attention of researchers as a desirable raw material for creating carbon quantum dots.Here we review the synthesis of carbon quantum dots from lignin,focusing on synthetic methods,properties,and applications in energy,and photocatalysis.Later,we propose some new development prospects from preparation methods,luminescence mechanism research,application,and commercial cost of lignin carbon quantum dots.Finally,based on this,the development prospects of this field are prospected and summarized.
基金supported by the NSFC-Zhejiang Joint Fund for Integration of Industrialization and Diversification(No.U1809214)the Natural Science Foundation of Zhejiang Province(Nos.LTGN23E080001 and LY20E080014)+1 种基金the Science and Technology Project of Zhoushan(No.2022C41011)the National Natural Science Foundation of China(No.22201251).
文摘Devising robust S-scheme photocatalysts is of central importance for achieving high-efficient micropollu-tant decontamination.However,the conscious optimization of S-scheme system with high performance remains a prime challenge.Herein,carbon quantum dots(CDs)and Mn_(0.5)Cd_(0.5)S(MCS)are mounted on BiOBr(BOB)microspheres,establishing an advanced S-scheme heterojunction with interfacial Bi-S bond.The interfacial Bi-S bonds function as superb channels at atomic-scale to abate the energy barrier for S-scheme charge transportation.Meanwhile,CDs serve as electron collectors to preserve highly reductive electrons from MCS,further augmenting the spatial separation of photo-carriers.Therefore,the optimized CDs/MCS/BOB(MBC)heterojunction manifests significantly strengthened tetracycline hydrochloride(TC)destruction activity and its reaction rate constant is approximately 3.1,2.2,2.1,and 1.5 folds that than that of MCS,BOB,BOB/CDs and MCS/BOB.In addition,MBC exhibits high stability and significant resistance to environmental interferences.The toxicology evaluation confirms the effective abatement of toxicity of TC after treatment.This achievement demonstrates the benefits of CDs-optimized S-scheme photosystems with chemical bonds for photocatalytic water decontamination.
基金supported by (Dr. Manika Khanuja, Nanomission, (DST)[DST/NM/NB/2018/203(G) (JMI)]UGC grant (No.F.4(201-FRP)/2015 (BSR))
文摘The endocrine-disrupting chemicals(EDCs)and antibiotics are causing negative effects on human beings and animals by disrupting the endocrine system and spreading antimicrobial resistance.The current need is to eradicate pharmaceutical waste from water bodies using advanced catalytic systems with high efficiency.Novel ternary carbon quantum dots(CQDs)decorated Z-Scheme WS_(2)-PANI nanocomposite was prepared by a green synthesis assisted in-situ polymerization for the photodegradation and detection of Estradiol(EST)and Nitrofurantoin(NFT).HRTEM micrographs revealed the formation of CQDs with a mean size of 4nm anchored on the surface of WS_(2)/PANI(width:PANI~20-30nm).The ternary nanocomposite showed excellent photocatalytic activity,degraded NFT(95.7%in 60min),and EST(96.6%in 60min).The rate kinetics study confirms the reaction followed pseudo first-order model.This heterostructure exhibited enhanced performances by modulating the energy level configuration,enhancing the absorption of visible light(2.4eV),and significantly improving the charge separation,three times higher than pristine WS_(2).These are highly favorable for increasing the generation of photoinduced charges and enhancing the overall performance of the catalyst.Further,the electrochemical sensor was prepared using CQDs@WS_(2)/PANI nanocomposite on a paper-based electrode.The CQDs@WS_(2)/PANI exhibit a linear response of 0.1-100nM,with a limit of detection of 13nM.This synergistic interfacial interaction resulted in the significantly improved electrochemical performance of the modified electrode.The proposed Z-scheme was justified by electron paramagnetic resonance(EPR)and scavenger experiment.An intermediate degradation pathway was also proposed.The synthesized materials were characterized using FESEM,HRTEM,XRD,FTIR,XPS,UV-visible spectroscopy,PL,and TRPL.Therefore,this study provides a direct approach to fabricate a heterojunction that combines two-dimensional,one dimensional,and zero-dimensional properties,enabling control over the energy level configuration and subsequent improvements in photocatalytic and electrocatalytic efficiency.
基金supported by National Natural Science Foundation of China(No.51873085)Natural Science Foundation of Liaoning Province-Outstanding Youth Foundation(No.2022-YQ-14)+2 种基金Liaoning Revitalization Talents Program(No.XLYC2007056)China Scholarship Council(CSC Scholarship,No.202006800009)the Shenyang Science and Technology Project(No.RC230707)。
文摘Precise control of luminescence in carbon quantum dots(CQDs),from single-color to full-color emission,is crucial for advancing their applications in biomedical imaging and display technologies.While CQDs luminescence is primarily influenced by conjugated domains and surface states,the underlying interaction mechanisms remain poorly understood.This study explores a graded nitro-engineering approach to simultaneously regulate surface states and sp^(2)conjugated domains through nitro(-NO_(2))modulation,enabling comprehensive color tuning.Using o-phenylenediamine(o-PD)as the carbon source and adjusting nitric acid(HNO_(3))concentrations,we synthesized tricolor-emitting nitro-functionalized CQDs(NO_(2)-CQDs).At lower-NO_(2) concentrations,luminescence is mainly influenced by surface states,where the electron-withdrawing effect of-NO_(2) enhancesπ-electron delocalization and stabilizes sp^(2)conjugation.With increasing-NO_(2) content,the lowest unoccupied molecular orbital(LUMO)energy level decreases(-2.12 eV to-3.39 eV),resulting in a red-shift in fluorescence.At higher-NO_(2) concentrations,luminescence is primarily affected by the sp^(2)conjugated domain,where steric hindrance reduces molecular planarity and conjugation,leading to a blue-shift in fluorescence as the sp^(2)domain size decreases(4.03 nm to 2.83 nm).Combining experimental results with density functional theory(DFT)calculations,we reveal the dual role of-NO2in modulating CQDs luminescence,an approach rarely achieved through surface functionalization.This work presents a novel strategy for precise tuning of CQDs luminescence across the visible spectrum.
基金financial support of National Key Research and Development Program of China(No.2021YFA1501500)the National Natural Science Foundation of China(Nos.22033008,22220102005,22171265)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZZ103).
文摘The growing environmental concerns regarding rare earth elements in fluorescent powders,along with high production costs,have increased the demand for sustainable alternatives.We propose a promising solution using luminescent metal-organic frameworks(LMOFs)with large surface areas and tunable pore structures,combined with organic carbon quantum dots(CQDs).This study develops a novel white lightemitting diode(WLED)fluorescent powder by incorporating yellow-fluorescent quantum dots(CQDs-Y)into blue-emitting LMOF(ZJU-28),forming the composite material CQDs-Y-n@ZJU-28.The composite exhibits excellent thermal and chemical stability,long-term storage performance,and emits warm white light(CIE:0.3277,0.3281)when subjected to excitation at 365 nm,along with an external quantum efficiency(EQE)of 8.85%.Furthermore,it exhibits tunable emission characteristics and promising LED performance,showcasing a color rendering index(CRI)of 78 and a correlated color temperature of 3384 K.The emitted light undergoes minimal deviation in color towards the white end of the spectrum in the temperature range of 277-437 K,making it an ideal candidate for advanced WLED applications.
文摘The authors regret to report some missing information in the synthetic reagents and associated changes of the paper.On page 511,the author information reads:“5.0 mmol of citric acid(C_(6)H_(8)O_(7)),5.0 mmol of ferric chloride hexahydrate(FeCl_(3)·6H_(2)O),and 10.0 mmol of o-phenylenediamine(C_(6)H_(8)N_(2))were combined with 40 mL of deionized water and magnetically stirred until fully dissolved.”
基金support and funding from the National Natural Science Foundation of China(No.52174047)。
文摘Hydrogels are widely used in reservoir flow control to enhanced oil recovery.However,challenges such as environmental contamination from conventional crosslinkers,poor solubility of crosslinking agents,and short gelation times under high-temperature conditions(e.g.,150℃)have hindered their practical application.Herein,we present the synthesis of amine-functionalized carbon quantum dots(NH_(2)-CQDs),which act as both a nano-crosslinker and a nano-reinforcing agent within hydrogel systems.The NH_(2)-CQDs-incorporated hydrogel can remain stability for 300 days under the conditions of a mineralization degree of 2.11×10^(4)mg/mL and 170℃,and has high tensile strength(371 kPa),good toughness(49.6 kJ/m~3),excellent viscoelasticity(G'=960 Pa,G"=460 Pa)and shear resistance.In addition,NH_(2)-CQDs adds many hydroxyl groups to the hydrogel,which can be attached to the surface of various substances.At the same time,micro-nano capsules containing NH_(2)-CQDs were formed by self-assembly of hydrophobic SiO_(2)on water droplets,the NH_(2)-CQDs solution is encapsulated in a capsule,and when stimulated by external conditions(temperature,pH,surfactant),the capsule releases the NH_(2)-CQDs solution,this method greatly delays the crosslinking time between polymer and crosslinker at high temperature.Under the condition of 170℃and pH=7,the gelation time of 10%hydrophobic SiO_(2)coated hydrogel is 44 times that of uncoated hydrogel,which can be effectively used for deep formation flow control,and CQD give hydrogels fluorescence properties that can be used for underground signal tracking.
基金the Department of Energy(DOE,Award Number:DE-FE0031997)for providing funds to support our research.
文摘Corn stover,an agricultural waste,was used to prepare nitrogen self-doped carbon quantum dots(CQDs)through a simple hydrothermal method with only water at near room temperature for the first time.The surface,electrochemical,and photovoltaic characteristics of CQDs doped TiO_(2)in dye-sensitized solar cells(DSSCs)were thoroughly and systematically examined.The average diameter of blue-fluorescence CQDs measured by a high-resolution transmission electron microscope(HR-TEM)was 4.63±0.87 nm,which consisted of polar functional groups.The highest occupied molecular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)energy of the biomass-derived CQDs,determined by the cyclic voltammetry(CV)test,were,−5.48 eV and−3.89 eV,respectively.The negative shift of flat band potential(Vfb)in CQDs incorporated photoanode implies the fermi level shifted upward.Experimental results revealed that the improved performance of DSSCs was due to charge transport enhancement and separation,which resulted in the improved energy level configuration between TiO_(2),CQDs,and electrolytes.In this regard,the CQDs serve as a mediator that enables charge carrier transport without hindrance.In this study,CQDs added to TiO_(2)+N719,increased short circuit current density(JSC)and power conversion efficiency(PCE)value by∼26.00%(10.13 to 12.69 mA/cm^(2))and 27.20%(4.78%to 6.08%),respectively.
基金funded by Shanghai Pujiang Program(21PJD022)Hunan Provincial Natural Science Foundation(2023JJ60522).
文摘Balancing the adsorption of OH⁻and 5-hydroxymethylfurfural(HMF)is crucial in optimizing the competing HMF oxidation reaction and oxygen evolution reaction,especially given the polymerization tendency of HMF in alkaline solutions.Herein,we present an innovative approach for rapidly synthesizing a NiFe bimetallic metalorganic framework(MOF)induced by electron-withdrawing carbon quantum dot(EW-CQD)via electron beam irradiation within 2 min.EW-CQD serve as structural regulators,expanding the NiFe-MOF interlayer spacing,increasing reactive site availability,and more effectively balancing the adsorption of OH6(-) and HMF,thereby significantly boosting the oxidation activity of HMF.The resulting EW-CQD-MOF exhibits a low potential of 1.36 V vs.RHE at 10 mA cm^(-2)and maintains excellent durability over 120 h.Comprehensive in situ characterization elucidates the HMF oxidation reaction pathway,showing high selectivity towards 2,5-furandicarboxylic acid(FDCA)under ambient conditions,with an impressive HMF conversion rate of 94%and FDCA selectivity of 96%within 6 h.These findings underscore the critical role of structural optimization and adsorption balance in catalytic performance enhancement and offer valuable insights for designing high-efficiency catalysts,advancing sustainable catalytic processes.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(NRF-2022R1A2C1011559,No.RS-2024-00405818 and NRF-2021M3H4A6A01045764)by the National Supercomputing Center with supercomputing resources including technical support(KSC-2024-CRE-0196)by Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Ministry of Science and ICT(No.RS-2024-00404712).
文摘Hydrogen evolution reaction(HER)in acidic media has been spotlighted for hydrogen production since it is a favourable kinetics with the supplied protons from a counterpart compared to that within alkaline environment.However,there is no choice but to use a platinum-based catalyst yet.As for a noble metal-free electrocatalyst,incorporation of earth-abundant transition metal(TM)atoms into nanocarbon platforms has been extensively adopted.Although a data-driven methodology facilitates the rational design of TM-anchored carbon catalysts,its practical application suffers from either a simplified theoretical model or the prohibitive cost and complexity of experimental data generation.Herein,an effective and facile catalyst design strategy is proposed based on machine learning(ML)and its model verification using electrochemical methods accompanied by density functional theory simulations.Based on a Bayesian genetic algorithm ML model,the Ni-incorporated carbon quantum dots(Ni@CQD)loaded on a three-dimensional reduced graphene oxide conductor are proposed as the best HER catalyst amongst the various TM-incorporated CQDs under the optimal conditions of catalyst loading,electrode type,and temperature and pH of electrolyte.The ML results are validated with electrochemical experiments,where the Ni@CQD catalyst exhibited superior HER activity,requiring an overpotential of 151 mV to achieve 10 mAcm^(−2) with a Tafel slope of 52 mV dec^(−1) and impressive durability in acidic media up to 100 h.This methodology can provide an effective route for the rational design of highly active electrocatalysts for commercial applications.
基金supported by the Central Guidance on Local Science and Technology Development Fund of Guangxi Province(Gui Ke ZY22096010)Guangxi Nat-ural Science Fundation(2023GXNSFAA026181)BAGUI Scholar Program of Guangxi Province of Chi-na,and Middle-aged and Young Teachers’Basic Abili-ty Promotion Project of Guangxi(2022KY0376).
文摘Carbon quantum dots(CQDs)have re-ceived increasing interest owing to their excellent optical and chemical characteristics,and high biocompatibil-ity.Herein,turmeric was employed as a carbon source to fabricate green CQDs(named WT-JHCQDs)by hydrother-mal technique.The fluorescence of WT-JHCQDs is particularly stable at differ-ent pH and high concentrations of NaCl.Moreover,WT-JHCQDs exhibit low cytotoxicity,good antioxidant properties,and outstanding biocompatibility.The WT-JHCQDs possess protruding ability of cell imaging and bacteria imaging.This work provides a promising strat-egy for designing excellent fluorescent probes for bioimaging.
基金performed as part of Luminescent MD,LLC’s Research Program(LMD-201)supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2023R1A2C1004109 and 2022R1I1A1A01070007)supported by Korea Energy(No.2024-Research and Development in Field Technology,Yeongheung-01).
文摘Nitrogen-doped carbon quantum dots(N-CQDs),synthesized via the rapid pyrolysis of ammonium citrate dibasic and ethylenediamine dihydrochloride,demonstrate remarkable chemiluminescence capabilities,emitting a vibrant blue-green light in peroxyoxalate chemiluminescence(PO-CL)reactions.Among these,a distinct variant of N-CQDs is an exceptionally sensitive biosensor,facilitating the swift detection of copper ions(Cu^(2+))within human plasma and urine samples.Upon rapid binding of N-CQDs and Cu^(2+),non-emissive complex forms due to intra-chemiluminescence resonance energy transfer(intra-CRET)initiated by the PO-CL reaction.Consequently,the brightness of the biosensor diminishes proportionally with increasing Cu^(2+)concentrations in human samples.Featuring a low sensing limit of 19.5 nM and an expansive dynamic range spanning from 0.05 to 3.8μM,this biosensor empowers the rapid and precise quantification of trace Cu^(2+)levels with exceptional accuracy and recovery rates.In alignment with copper quantification guidelines set forth by the Environmental Protection Agency(EPA)and the National Institutes of Health(NIH),this selective biosensor stands as a cutting-edge monitoring tool,poised to advance analytical capabilities in various fields.
基金supported by The Natural Science Foundation of the Jiangsu Higher Education Institutions of China(19KJB150019)Youth Science and Technology Talents Enrollment Project of the Jiangsu Association of Science and Technology。
文摘Zero-dimensional(0D)carbon quantum dots(CQDs),as a nanocarbon material in the carbon family,have garnered increasing attention in recent years due to their outstanding features of low cost,nontoxicity,large surface area,high electrical conductivity,and rich surface functional groups.By virtue of their rapid electron transfer and large surface area,CQDs also emerge as promising functional materials for the applications in energy-conversion sectors through electrocatalysis.Besides,the rich functional groups on the surface of CQDs offer abundant anchoring sites and active sites for the engineering of multicomponent and high-performance composite materials.More importantly,the heteroatom in the CQDs could effectively tailor the charge distribution to promote the electron transfer via internal interactions,which is crucial to the enhancement of electrocatalytic performance.Herein,an overview about recent progress in preparing CQDs-based composites and employing them as promising electrode materials to promote the catalytic activity and stability for electrocatalysis is provided.The introduced CQDs could enhance the conductivity,modify the morphology and crystal phase,optimize the electronic structure,and provide more active centers and defect sites of composites.After establishing a deep understanding of the relationship between CQDs and electrocatalytic performances,the issues and challenges for the development of CQDs-based composites are discussed.
基金financial support from Project funded by China postdoctoral Science Foundation (No. 2018M640681)
文摘The development of large-scale synthetic methods for high quality carbon quantum dots(CQDs) is fundamental to their applications.However,the macroscopic preparation and scale up synthetic of CQDs is still in its infancy.Here,we report a facile,green,kilogram-scale synthesis of high quality fluorescent CQDs derived from poplar leaves via a one-step hydrothermal method.Notably,the throughput of CQDs can reach a level up to as high as 1.4975 kg in one pot.The structure and properties of the as-prepared CQDs were assessed through TEM,XRD,XPS and various spectroscopic methods.The obtained high quality CQD s with a photoluminescent quantum yield of 10.64% showed remarkable stability in aqueous media,rich functional groups,high photostability,consistent photoluminescence within biological pH range and low cytotoxicity.On account of these good properties,we demonstrated the multifunctional application to electrocatalytic water splitting,Fe^3+ sensing and bioimaging.It showed remarkable electrocatalytic activity,Fe^3+ sensitivity and good biocompatibility.This study provides a green,facile,inexpensive and large-scale method for producing high quality CQDs,which provides application value for large-scale production of CQDs.
基金financially supported by National Natural Science Foundation of China(21601057)Hunan Provincial Natural Science Foundation of China(2018JJ3116)Excellent Youth Fund of Hunan Provincial Education Department(18B298)
文摘Carbon quantum dots(CQDs)as a new class of emerging materials have gradually drawn researchers’concern in recent years.In this work,the graphitic CQDs are prepared through a scalable approach,achieving a high yield with more than 50%.The obtained CQDs are further used as structure-directing and conductive agents to synthesize novel N,S-CQDs/NiCo2S4 composite cathode materials,manifesting the enhanced electrochemical properties resulted from the synergistic effect of highly conductive N,S-codoped CQDs offering fast electronic transport and unique micro-/nanostructured NiCo2S4 microspheres with Faradaic redox characteristic contributing large capacity.Moreover,the nitrogen-doped reduced graphene oxide(N-rGO)/Fe2O3 composite anode materials exhibit ultrahigh specific capacity as well as significantly improved rate property and cycle performance originating from the high-capacity prism-like Fe2O3 hexahedrons tightly wrapped by highly conductive N-rGO.A novel alkaline aqueous battery assembled by these materials displays a specific energy(50.2 Wh kg^−1),ultrahigh specific power(9.7 kW kg^−1)and excellent cycling performance with 91.5%of capacity retention at 3 A g^−1 for 5000 cycles.The present research offers a valuable guidance for the exploitation of advanced energy storage devices by the rational design and selection of battery/capacitive composite materials.
基金financial support from the key project of the National Natural Science Foundation of China (U1463204)the project of National Natural Science Foundation of China (NSFC) (20903023,21173045)+4 种基金the Award Program for Minjiang Scholar Professorshipthe Natural Science Foundation (NSF) of Fujian Province for Distinguished Young Investigator Grant (2012J06003)the Independent Research Project of State Key Laboratory of Photocatalysis on Energy and Environment (No.2014A05)the 1st Program of Fujian Province for Top Creative Young Talentsthe Program for Returned High-Level Overseas Chinese Scholars of Fujian Province
文摘As a new member of carbon material family, carbon quantum dots (CQDs) have attracted tremendous attentions for their potentials in the heterogeneous photocatalysis applications. Due to the unique microstructure and optical properties, the roles of CQDs played in the CQDs-based photocatalytic systems have been found to be diverse with the continuous researches in this regard. Herein, we provide a concise minireview to elaborate the multifarious roles of CQDs in photocatalysis, including photoelectron mediator and acceptor, photosensitizer, photocatalyst, reducing agent for metal salt, enhancing adsorption capacity and spectral converter. In addition, the perspectives on future research trends and challenges are proposed, which are anticipated to stimulate further research into this promising field on designing a variety of efficient CQDs-based photocatalysts for solar energy conversion. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B. V. and Science Press. All rights reserved.
文摘Development of efficient heterostructured photocatalysts that respond to visible light remains a considerable challenge.We herein show the synthesis of ZnIn2S4/carbon quantum dot hybrid photocatalysts with flowerlike microspheres via a facile solvothermal method.The ZnIn2S4/carbon quantum dot flowerlike microspheres display enhanced photocatalytic and photoelectrochemical activity compared with that of pure ZnIn2S4.With a content of only 0.5 wt%carbon quantum dots,93%of Cr(VI)is reduced under visible‐light irradiation at 40 min.As a co‐catalyst,the carbon quantum dots improve the light absorption and lengthen the lifetime of charge carriers,consequently enhancing the photocatalytic and photoelectrochemical activity.
基金Innovative Research Group of the National Natural Science Foundation of China(NFSC)(No.51721006)China Postdoctoral Science Foundation(No.2017M620132)
文摘A novel carbon quantum dots modified potassium titanate nanotubes(CQDs/K2 Ti6 O13)composite photocatalyst was synthesized by hydrothermal treatment combined with calcination.X-ray diffraction(XRD)pattern and transmission electron microscopy(TEM)indicated formation of potassium titanate nanotubes and successful deposition of CQDs onto K2 Ti6 O13.The photocatalytic performance of CQDs/K2 Ti6 O13 composite was evaluated by degradation of amoxicillin(AMX)under the irradiation of visible light and lights with the wavelengths of 365,385,420,450,485,520,595 and 630 nm.The results showed that the photocatalytic activity of CQDs/K2 Ti6 O13 hybrid material was greatly enhanced compared with the neat K2 Ti6 O13 calcined at 300℃.The narrowed band gap energy(Eg)and transfer of photo-excited electron by CQDs inhibited the immediate combination of electron-hole pairs,thus promoting photocatalytic activity.Moreover,CQ,Ds/K2 Ti6 O13 exhibited a broad spectrum of photocatalytic ability and it was interesting that the photocatalytic activity decreased with the increase of the irradiation wavelength.Reactive oxygen species(ROS)quenching tests suggested the hole(h^+)and hydroxyl radical(^·OH)played the primary roles in photocatalytic degradation of AMX.Moreover,CQ.Ds/K2 Ti6 O13 showed good reusability for AMX photocatalytic degradation after five successive runs.This study proposed an available method for titanate nanomaterials modification,and the developed novel CQDs/K2 Ti6 O13hyb rid material is p ro mising fo r potential application on antibiotics removal fro m water and wastewater.
文摘Carbon quantum dots(CQDs)are emerging as the new-generation light absorber for solar energy conversion.However,the low photosensitization efficiency of CQDs is one of the current bottlenecks impeding their large-scale practical applications in photocatalysis.Therefore,developing a facile approach for the engineering and functionalization of CQDs-based composites to improve the photosensitization efficiency of CQDs is highly desirable.On account of the abundant functional groups,especially oxygen-containing functional groups such as carbonyl,carboxyl,and hydroxyl present on their surface,CQDs can be readily combined with various organic molecules or polymers as a surface passivation component to reduce the nonradioactive surface recombination of photo-generated charge carriers,thus enabling the CQDs to exhibit strong photoluminescence in the visible and near-infrared spectral regions.Consequently,polymer passivation has been demonstrated as an ideal strategy to make it accessible for improving the sensitization efficiency of CQDs in photocatalytic applications.Branched polyethylenimine(BPEI)is one of polymers that contains a high density of amine groups and exhibits high electron mobility,which can be used as an electron injection material at the interface of nanomaterials.Besides,the BPEI polymer with amino groups exhibiting positive charge has been utilized for designing heterogeneous catalysts by an electrostatic self-assembly strategy.Therefore,BPEI is expected to modify the surface of inorganic oxides semiconductor to enhance the photosensitization efficiency of CQDs under visible light.However,to date,the study in this regard has been still unavailable In this work,we developed a facile approach to engineer well-distributed CQDs via electrostatic interaction on BPEI passivated TiO2 composites(BTC)as photocatalysts.The BTC composites with an optimal loading of 5%(w,mass fraction)CQDs outperformed the TiO2/CQDs(TC)composite and referential BPEI/SiO2/CQDs(BSC)composites for the photoreduction of 4-nitroaniline under visible light irradiation.The structure of the fabricated BTC composites was systematically investigated by the combined use of structural and spectral characterizations,demonstrating that the photosensitizer CQDs contacted well with the BPEI modified TiO2 nanoparticles.The comparison characterizations revealed that BPEI facilitated the dissociation and transfer of excitons as an electron transfer channel.The as-prepared BTC composites benefited from the favorable interfacial contact and effective transfer of photo-generated charge carriers,and thus manifested superior photocatalytic activity to the TC composite.It is expected that this strategy would be extended to other wide band gap semiconductor photocatalyst systems and open up new possibilities in designing efficient CQDs-based semiconductor artificial light harvesting systems by interfacial optimization.
