The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS...The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS QDs and hollow nanotube In_(2)O_(3)is successfully achieved using an electrostatic self-assembly method.Under visible light irradiation,all CdS-In_(2)O_(3)composites exhibit higher hydrogen evolution efficiency compared to pure CdS QDs.Notably,the photocatalytic H_(2)evolution rate of the optimal CdS-7%In_(2)O_(3)composite is determined to be 2258.59μmol g^(−1)h^(−1),approximately 12.3 times higher than that of pure CdS.The cyclic test indicates that the CdS-In_(2)O_(3)composite maintains considerable activity even after 5 cycles,indicating its excellent stability.In situ X-ray photoelectron spectroscopy and density functional theory calculations confirm that carrier migration in CdS-In_(2)O_(3)composites adheres to a typical S-scheme heterojunction mechanism.Additionally,a series of characterizations demonstrate that the formation of S-scheme heterojunctions between In_(2)O_(3)and CdS inhibits charge recombination and accelerates the separation and migration of photogenerated carriers in the CdS QDs,thus achieving enhanced photocatalytic performance.This work elucidates the pivotal role of S-scheme heterojunctions in photocatalytic H_(2)production and offers novel insights into the construction of effective composite photocatalysts.展开更多
Water purification systems based on transition metal dichalcogenides face significant challenges,including lack of reactivity under dark conditions,scarcity of catalytically active sites,and rapid recombination of pho...Water purification systems based on transition metal dichalcogenides face significant challenges,including lack of reactivity under dark conditions,scarcity of catalytically active sites,and rapid recombination of photogenerated charge carriers.Simultaneously increasing the number of active sites and improving charge separation efficiency has proven difficult.In this study,we present a novel approach combining molybdenum(Mo) monoatomic doping and size engineering to produce a series of Mo-ReS_(2) quantum dots(MR QDs) with controllable dimensions.High-resolution structural characterization,first-principle calculations,and piezo force microscopy reveal that Mo monoatomic doping enhances the lattice asymmetry,thereby improving the piezoelectric properties.The resulting piezoelectric polarization and the generated built-in electric field significantly improve charge separation efficiency,leading to optimized photocatalytic performance.Additionally,the doping strategy increases the number of active sites and improves the adsorption of intermediate radicals,substantially boosting photo-sterilization efficiency.Our results demonstrate the elimination of 99.95% of Escherichia coli and 100.00% of Staphylococcus aureus within 30 min.Furthermore,we developed a self-purification system simulating water drainage,utilizing low-frequency water streams to trigger the piezoelectric behavior of MR QDs,achieving piezoelectric synergistic photodegradation.This innovative approach provides a more environmentally friendly and economical method for water self-purification,paving the way for advanced water treatment technologies.展开更多
Imines play a pivotal role as multifunctional intermediates in pharmaceutical and biological applications,and their selective synthesis under mild conditions has attracted increasing interest.In this study,a covalent-...Imines play a pivotal role as multifunctional intermediates in pharmaceutical and biological applications,and their selective synthesis under mild conditions has attracted increasing interest.In this study,a covalent-organic frameworks(COFs)modified with CeO_(2)quantum dots(QDs)were prepared through a simple chemical reaction using LZU1 COFs and Ce(NO_(3))_(3)·6H_(2)O serving as precursors.The optimized5CeO_(2)QDs@LZU1 decorated with about 3.9 wt%CeO_(2)QDs demonstrates excellent performance in the photocatalytic selective oxidative of amines in visible light conditions,achieving nearly 100%benzylamine conversion and over 99%imine selectivity within 6 h,which is significantly superior to that of pure LZU1 and CeO_(2).The remarkable enhancement in activity is mainly attributed to the fact that the interaction between CeO_(2)QDs and LZU1 COF in 5CeO_(2)QDs@LZU1 improves the visible light response and concurrently promotes the separation efficiency of photogenerated e-and h+pairs.Broad substrate scope also provides a prospect for the industrial synthesis of various imines.Our findings not only expand the application range of COFs by incorporating QDs but also lay the groundwork for their further rational design and optimization.展开更多
TiO_(2)has been widely studied as one of the most promising anode materials for lithium-ion batteries(LIBs)due to good structural stability and small volume changes.However,its applications are still greatly affected ...TiO_(2)has been widely studied as one of the most promising anode materials for lithium-ion batteries(LIBs)due to good structural stability and small volume changes.However,its applications are still greatly affected by its poor electrical conductivity.In this work,ultrasmall TiO_(2)quantum dots(QDs)are firmly grown onto 2D Ti_(3)C_(2)T_(x)nanosheets(A-TiO_(2)/Ti_(3)C_(2)T_(x)),benefiting from the positive regulation of(3-aminopropyl)triethoxysilane(APTES).Interestingly,SiO_(2)nanoparticles produced by the hydrolysis of APTES can strengthen the strong coupling of TiO_(2)QDs with Ti_(3)C_(2)T_(x),thereby enhancing the structural integrity of the composite.As expected,the A-TiO_(2)/Ti_(3)C_(2)T_(x)composite demonstrates an exceptional lithium storage performance,achieving a high capacity of 425.4 m Ah/g for 400 cycles at 0.1 A/g,and an outstanding long-term cycling stability.In-situ electrochemical impedance spectroscopy and theoretical analysis unconver that the superior lithium storage performance is attributed to its unique heterostructure and in-situ N doping derived from APTES,which not only reduces the Li^(+)adsorption energy,but also gives the fast charge transfer dynamics.展开更多
TiNb_(2)O_(7)has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries.However,limited by the slow electron/ion transport kinetics,and insufficient active sites in the bul...TiNb_(2)O_(7)has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries.However,limited by the slow electron/ion transport kinetics,and insufficient active sites in the bulk structure,the TiNb_(2)O_(7)electrode still suffers from unsatisfactory lithium storage performance.Herein,we demonstrate a spatially confined strategy toward a novel TiNb_(2)O_(7)-NMC/MXene composite through a triblock copolymer-directed one-pot solvothermal route,where TiNb_(2)O_(7)quantum dots with a particle size of 2-3 nm are evenly embedded into N-doped mesoporous carbon(NMC)and Ti_(3)C_(2)T_(X)MXene.Impressively,the as-prepared TiNb_(2)O_(7)-NMC/MXene anode exhibits a high reversible capacity(486.2 mAh g^(-1)at 0.1 A g^(-1)after 100 cycles)and long cycle lifespan(363.4 mAh g^(-1)at ss1 A g^(-1)after 500 cycles).Both experimental and theorical results further demonstrate that such a superior lithium storage performance is mainly ascribed to the synergistic effect among 0D TiNb_(2)O_(7)quantum dots,2D Ti_(3)C_(2)T_(X)MXene nanosheets,and N-doped mesoporous carbon.The strategy presented also opens up new horizon for space-confined preparation of high-performance electrode materials.展开更多
MXenes,a new family of two-dimensional(2D)materials with excellent electronic conductivity and hydrophilicity,have shown distinctive advantages as a highly conductive matrix material for lithium-ion battery anodes.Her...MXenes,a new family of two-dimensional(2D)materials with excellent electronic conductivity and hydrophilicity,have shown distinctive advantages as a highly conductive matrix material for lithium-ion battery anodes.Herein,a facile electrostatic self-assembly of SnO2 quantum dots(QDs)on Ti3C2Tx MXene sheets is proposed.The as-prepared SnO2/MXene hybrids have a unique 0D-2D structure,in which the 0D SnO2 QDs(~4.7 nm)are uniformly distributed over 2D Ti3C2Tx MXene sheets with controllable loading amount.The SnO2 QDs serve as a high capacity provider and the“spacer”to prevent the MXene sheets from restacking;the highly conductive Ti3C2Tx MXene can not only provide efficient pathways for fast transport of electrons and Li ions,but also buffer the volume change of SnO2 during lithiation/delithiation by confining SnO2 QDs between the MXene nanosheets.Therefore,the 0D-2D SnO2 QDs/MXene hybrids deliver superior lithium storage properties with high capacity(887.4 mAh g?1 at 50 mA g?1),stable cycle performance(659.8 mAh g?1 at 100 mA g?1 after 100 cycles with a capacity retention of 91%)and excellent rate performance(364 mAh g?1 at 3 A g?1),making it a promising anode material for lithium-ion batteries.展开更多
Photocatalytic water splitting is a promising method for hydrogen production.Numerous efficient photocatalysts have been synthesized and utilized.However,photocatalysts without a noble metal as the co-catalyst have be...Photocatalytic water splitting is a promising method for hydrogen production.Numerous efficient photocatalysts have been synthesized and utilized.However,photocatalysts without a noble metal as the co-catalyst have been rarely reported.Herein,a CoP co-catalyst-modified graphitic-C3N4(g-C3N4/CoP)is investigated for photocatalytic water splitting to produce H2.The g-C3N4/CoP composite is synthesized in two steps.The first step is related to thermal decomposition,and the second step involves an electroless plating technique.The photocatalytic activity for hydrogen evolution reactions of g-C3N4 is distinctly increased by loading the appropriate amount of CoP quantum dots(QDs).Among the as-synthesized samples,the optimized one(g-C3N4/CoP-4%)shows exceptional photocatalytic activity as compared with pristine g-C3N4,generating H2 at a rate of 936μmol g^-1 h^-1,even higher than that of g-C3N4 with 4 wt%Pt(665μmol g^-1 h^-1).The UV-visible and optical absorption behavior confirms that g-C3N4 has an absorption edge at 451 nm,but after being composited with CoP,g-C3N4/CoP-4%has an absorption edge at 497 nm.Furthermore,photoluminescence and photocurrent measurements confirm that loading CoP QDs to pristine g-C3N4 not only enhances the charge separation,but also improves the transfer of photogenerated e--h+pairs,thus improving the photocatalytic performance of the catalyst to generate H2.This work demonstrates a feasible strategy for the synthesis of highly efficient metal phosphide-loaded g-C3N4 for hydrogen generation.展开更多
H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness.As a sustainable H2-generation method,photocatalytic H2 production by water split...H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness.As a sustainable H2-generation method,photocatalytic H2 production by water splitting has attracted much interest.Here,oil-soluble ZnxCd1-xS quantum dot(ZCS QD)with a uniform particle size distribution were prepared by a hot-injection method.However,no photocatalytic H2-production activity was observed for the oil-soluble ZCS QD due to its hydrophobicity.Thus,the oil-soluble ZCS QD was converted into a water-soluble ZCS QD by a ligand-exchange method.The water-soluble ZCS QD exhibited excellent photocatalytic H2-production performance in the presence of glycerin and Ni^2+,with an apparent quantum efficiency of 15.9%under irradiation of 420 nm light.Further,the photocatalytic H2-generation activity of the ZCS QD was~10.7 times higher than that of the ZnxCd1-xS relative samples prepared by the conventional co-precipitation method.This work will inspire the design and fabrication of other semiconductor QD photocatalysts because QD exhibits excellent separation efficiency for photogenerated electron-hole pairs due to its small crystallite size.展开更多
Herein,we report a novel ternary material comprised of Ag nanoparticles and carbon quantum dots(CDs),which are co-loaded using 2D Bi4Ti3O12(BIT)sheets.In this system,Ag can be applied as excited electron-hole pairs in...Herein,we report a novel ternary material comprised of Ag nanoparticles and carbon quantum dots(CDs),which are co-loaded using 2D Bi4Ti3O12(BIT)sheets.In this system,Ag can be applied as excited electron-hole pairs in the Bi4Ti3O12 by transferring the plasmonic energy from the metal to the semiconductor.The surface plasmon resonance of Ag can promote the electron transfer properties of the CDs,thereby improving the separation efficiency of the electron-hole pairs.Meanwhile,the CDs can act as an electron buffer to decrease the recombination rate of the electron hole.Moreover,CDs are prepared using a biomaterial,which can provide a chemical group to enhance the electron transfer and connection.The synergistic effects of CDs,Ag,and BIT enable the design of a photocatalytic application with a remarkably improved efficiency and operational stability.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
In this work,Eu^(3+)-doped CsPbCl_(2)Br_(1) in borosilicate glass was successfully synthesized by the melt quenching annealing technique and crystallization method.This work reports a novel Eu^(3+)-doped CsPbCl_(2)Br_...In this work,Eu^(3+)-doped CsPbCl_(2)Br_(1) in borosilicate glass was successfully synthesized by the melt quenching annealing technique and crystallization method.This work reports a novel Eu^(3+)-doped CsPbCl_(2)Br_(1) perovskite quantum dots(QDs)glass with high sensitivity for optical temperature sensing.The relation of fluorescence intensity ratio(FIR)with the temperature was studied in the temperature range of 80-440 K.Notably,the maximum absolute temperature sensitivity(Sa)and relative temperature sensitivity(Sr)of Eu^(3+)-doped CsPbCl_(2)Br_(1) perovskite QDs glass can reach as high as 0.0315 K-1 and3.097%/K,respectively.Meanwhile,Eu^(3+)-doped CsPbCl_(2)Br_(1) QDs glass demonstrates good water resistance,excellent thermal and cold cycling stability performance,The Eu^(3+)-doped QDs glass materials can bring inspiration to the future exploration of rare earth ion-doped QDs glass material on the application of optical temperature sensing in the future.展开更多
Formaldehyde(HCHO) is widely known as an indoor air pollutant,and the monitoring of the gas has significant importance.However,most HCHO sensing materials do not have low detection limits and operate at high temperatu...Formaldehyde(HCHO) is widely known as an indoor air pollutant,and the monitoring of the gas has significant importance.However,most HCHO sensing materials do not have low detection limits and operate at high temperatures.Herein,two-dimensional(2D) mesoporous ultrathin SnO_(2) modified with nitrogen-doped graphene quantum dots(N-GQDs) was synthesized.The N-GQDs/SnO_(2) nanocomposite demonstrated high efficiency for HCHO detection.With the addition of 1.00 wt%N-GQDs,the response(Ra/Rg) of SnO_(2) gas sensor increased from 120 to 361 at 60℃ for the detection of 10×10^(-6) HCHO.In addition,the corresponding detection limit was as low as 10×10^(-9).Moreover,the sensor exhibited excellent selectivity and stability for the detection of HCHO.The enhanced sensing performance was attributed to both the large specific surface area of SnO_(2) and electron regulation of N-GQDs.Therefore,this study presents a novel HCHO sensor,and it expands the research and application potential of GQDs nanocomposites.展开更多
The 2 D nanomaterials have achieved the superlubrication property whatever in solid or liquid lubrication in recent years.However,whether or not the nanosheets can stably disperse in oils and smoothly enter into the a...The 2 D nanomaterials have achieved the superlubrication property whatever in solid or liquid lubrication in recent years.However,whether or not the nanosheets can stably disperse in oils and smoothly enter into the asperity of friction pairs is crucial for exerting the function of antifriction.The structure of 2 D QDs is desirable for addressing these issues due to its smaller 3 D size.In this study,we developed a facile preparation process for WS_(2) QDs with uniform 2 nm size from nanosheets via hydrothermal-assisted grinding approach.The structure of the as-obtained WS_(2) QDs was determined by a series of characterizations.The results showed that the as-obtained WS_(2) QDs exhibited the typical spectrum features of nanosized quantum dot.The results of the tribological performance in grease verified that the average friction coefficient(ACOFs) and wear volume(AWVs) were decreased by 7.89% and 63.90%relative to grease,respectively,exhibiting a preferable friction reducing and wear resistance.展开更多
As a novel zero-dimensional(0D)material,metal carbides and/or carbonitrides(MXenes)quantum dots(MQDs)show unique photoluminescence properties and excellent biocompatibility.However,due to the limited synthesis methods...As a novel zero-dimensional(0D)material,metal carbides and/or carbonitrides(MXenes)quantum dots(MQDs)show unique photoluminescence properties and excellent biocompatibility.However,due to the limited synthesis methods and research to date,many new features have yet to be uncovered.Here,to explore their new properties and expand biological applications,chlorine and nitrogen co-doped Ti_(3)C_(2)MXene quantum dots(Cl,N-Ti_(3)C_(2)MQDs)were designed and synthesized,and their hydroxyl radical scavenging properties were investigated for the first time,revealing outstanding performance.Cl,N-Ti_(3)C_(2)MQDs was directly stripped from bulk Ti_(3)Al C_(2)by electrochemical etching,while N and Cl are successfully introduced to carbon skeleton and Ti boundaries in the etching process by electrochemical reactions between selected electrolytes and Ti_(3)C_(2)skeleton,respectively.The obtained Cl,N-Ti_(3)C_(2)MQDs exhibit large surface-to-volume ratio due to small particle size(ca.3.45 nm)and excellent higher scavenging activity(93.3%)and lower usage(12.5μg/m L)towards hydroxyl radicals than the previous reported graphene-based nanoparticles.The underlying mechanism of scavenging activity was also studied based on the reduction experiment with potassium permanganate(KMnO_(4)).The reducing ability of the intrinsic Ti_(3)C_(2)structure and electron donation of double dopants are the main contributors to the outstanding scavenging activity.展开更多
Mix-dimensional van der Waals heterostructures(vdWHs)have inspired worldwide interests and efforts in the field of ad-vanced electronics and optoelectronics.The fundamental understanding of interfacial charge transfer...Mix-dimensional van der Waals heterostructures(vdWHs)have inspired worldwide interests and efforts in the field of ad-vanced electronics and optoelectronics.The fundamental understanding of interfacial charge transfer is of vital import-ance for guiding the design of functional optoelectronic applications.In this work,type-Ⅱ0D-2D CdSe/ZnS quantum dots/MoS_(2)vdWHs are designed to study the light-triggered interfacial charge behaviors and enhanced optoelectronic performances.From spectral measurements in both steady and transient states,the phenomena of suppressed photolu-minescence(PL)emissions,shifted Raman signals and changed PL lifetimes provide strong evidences of efficient charge transfer at the 0D-2D interface.A series of spectral evolutions of heterostructures with various QDs overlapping concentrations at different laser powers are analyzed in details,which clarifies the dynamic competition between exciton and trion during an efficient doping of 3.9×10^(13)cm^(−2).The enhanced photoresponses(1.57×10^(4)A·W^(-1))and detectivities(2.86×10^(11)Jones)in 0D/2D phototransistors further demonstrate that the light-induced charge transfer is still a feasible way to optimize the performance of optoelectronic devices.These results are expected to inspire the basic understand-ing of interfacial physics at 0D/2D interfaces,and shed the light on promoting the development of mixed-dimensional op-toelectronic devices in the near future.展开更多
Smartcombination of manifold carbonaceous materials with admirable functionalities(like full of pores/functional groups,high specific surface area) is still a mainstream/preferential way to address knotty issues of po...Smartcombination of manifold carbonaceous materials with admirable functionalities(like full of pores/functional groups,high specific surface area) is still a mainstream/preferential way to address knotty issues of polysulfides dissolution/shuttling and poor electrical conductivity for S-based cathodes.However,extensive use of conductive carbon fillers in cell designs/technology would induce electrolytic overconsumption and thereby shelve high-energy-density promise of Li-S cells.To cut down carbon usage,we propose the incorporation of multi-functionalized NiFe2O4 quantum dots(QDs) as affordable additive substitutes.The total carbon content can be greatly curtailed from 26%(in traditional S/C cathodes) to a low/commercial mass ratio(~5%).Particularly,note that NiFe2O4 QDs additives own superb chemisorption interactions with soluble Li2Sn molecules and proper catalytic features facilitating polysulfide phase conversions and can also strengthen charge-transfer capability/redox kinetics of overall cathode systems.Benefiting from these intrinsic properties,such hybrid cathodes demonstrate prominent rate behaviors(decent capacity retention with ~526 mAh g^-1 even at 5 A g^-1) and stable cyclic performance in LiNO3-free electrolytes(only ~0.08% capacity decay per cycle in 500 cycles at 0.2 A g^-1).This work may arouse tremendous research interest in seeking other alternative QDs and offer an economical/more applicable methodology to construct low-carbon-content electrodes for practical usage.展开更多
It has been demonstrated that the conductivity and electrochemical properties of TiO2 nanomate rials can be significantly improved by an incorporation of carbon additives.In the study,we develop a novel Ndoped TiO2 me...It has been demonstrated that the conductivity and electrochemical properties of TiO2 nanomate rials can be significantly improved by an incorporation of carbon additives.In the study,we develop a novel Ndoped TiO2 mesoporous nanostructure via the addition of carbon quantum dots(CQDs)solution following a scalable hydrothermal process.The as-made TiO2 product shows well-defined morphology,high conductivity,large surface area,and abundant mesopores.When evaluated as anodes for sodiumion batteries,the CQDs@TiO2 product annealed at 500℃exhibits a superior sodium storage capability.It delivers a high reversible capacity of 168.8 mAh/g at 100 mA/g over 500 cycles and long cycling stability.The remarkable performance of CQDs@TiO2 mainly arises from the large surface area and mesoporous architecture constructed by ultrathin TiO2 nanosheets,as well as the full coope ration between CQDs and TiO2.展开更多
Fabrication of well-designed heterojunctions is an extraordinarily attractive pathway for boosting the photocatalytic activity toward CO_(2) photoreduction.Herein,a novel kind of na nosheet-based intercalation hybrid ...Fabrication of well-designed heterojunctions is an extraordinarily attractive pathway for boosting the photocatalytic activity toward CO_(2) photoreduction.Herein,a novel kind of na nosheet-based intercalation hybrid coupled with CdSe quantum dots(QDs) was successfully fabricated by a facile solvothermal method and served as photocatalyst for full-spectrum-light-driven CO_(2) reduction.Ultra-small CdSe QDs were rationally in-situ introduced and coupled with lamellar ZnSe-intercalation hybrid nanosheet,resulting in the formation of CdSe Q.Ds/ZnSe hybrid heterojunction.Significantly,the concentration of Cd^(2+) could change directly the crystallinity and micromorphology of ZnSe intercalation hybrid,which in turn would impact on the photocatalysis activity.The optimized CdSe QDs/ZnSe hybrid-5 composite demonstrated a considerable CO yield rate of the 25.6 μmol g^(-1) h^(-1) without any additional cocatalysts or sacrificial agents assisting,making it one of the best reported performance toward CO_(2) photoreduction under full-spectrum light.The elevated CO_(2) photoreduction activity could be attributed to the special surface heterojunction,leading to improving the ability of light absorption and promoting the separation/transfer of photogenerated carriers.This present study developed a new strategy for designing inorganic-organic heterojunctions with enhanced photocatalyst for CO_(2) photoreduction and provided an available way to simultaneously mitigate the greenhouse effect and alleviate energy shortage pressure.展开更多
Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐di...Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐dimensional(2D)g‐C3N4nanoplates and zero‐dimensional(0D)MoS2quantum dots(QDs)was prepared through the combination of a hydrothermal process and microemulsion preparation.The morphologies,structures,and optical properties of the as‐prepared photocatalysts were characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,atomic force microscopy,transmission electron microscopy,and UV‐vis diffuse reflectance spectroscopy.In addition,the photocatalytic performances of the prepared2D/0D hybrid composites were evaluated based on the photodegradation of rhodamine B under visible‐light irradiation.The results demonstrated that the introduction of MoS2QDs to g‐C3N4greatly enhanced the photocatalytic efficiency.For the optimum7%MoS2QD/g‐C3N4photocatalyst,the degradation rate constant was8.8times greater than that of pure g‐C3N4under visible‐light irradiation.Photocurrent and electrochemical impedance spectroscopy results further demonstrated that the MoS2QD/g‐C3N4composites exhibited higher photocurrent density and lower chargetransfer resistance than those of the pure g‐C3N4or MoS2QDs.Active species trapping,terephthalic acid photoluminescence,and nitro blue tetrazolium transformation experiments were performed to investigate the evolution of reactive oxygen species,including hydroxyl radicals and superoxide radicals.The possible enhanced photocatalytic mechanism was attributed to a direct Z‐scheme system,which not only can increase the separation efficiency of photogenerated electron‐hole pairs but also possesses excellent oxidation and reduction ability for high photocatalytic performances.This work provides an effective synthesis approach and insight to help develop other C3N4‐based direct Z‐scheme photocatalytic systems for environmental purification and energy conversion.展开更多
Depositing a cocatalyst has proven to be an important strategy for improving the photoelectrochemical(PEC)water-splitting efficiency of photoanodes.In this study,Ni(OH)2 quantum dots(Ni(OH)2 QDs)were deposited in situ...Depositing a cocatalyst has proven to be an important strategy for improving the photoelectrochemical(PEC)water-splitting efficiency of photoanodes.In this study,Ni(OH)2 quantum dots(Ni(OH)2 QDs)were deposited in situ onto anα-Fe_(2)O_(3)photoanode via a chelation-mediated hydrolysis method.The photocurrent density of the Ni(OH)2 QDs/α-Fe_(2)O_(3)photoanode reached 1.93 mA·cm^(−2)at 1.23 V vs.RHE,which is 3.5 times that ofα-Fe_(2)O_(3),and an onset potential with a negative shift of ca.100 mV was achieved.More importantly,the Ni(OH)2 QDs exhibited excellent stability in maintaining PEC water oxidation at a high current density,which is attributed to the ultra-small crystalline size,allowing for the rapid acceptance of holes fromα-Fe_(2)O_(3)to Ni(OH)_(2)QDs,formation of active sites for water oxidation,and hole transfer from the active sites to water molecules.Further(photo)electrochemical analysis suggests that Ni(OH)_(2)QDs not only provide maximal active sites for water oxidation but also suppress charge recombination by passivating the surface states ofα-Fe_(2)O_(3),thereby significantly enhancing the water oxidation kinetics over theα-Fe_(2)O_(3)surface.展开更多
文摘The rapid recombination of photogenerated carriers poses a significant limitation on the use of CdS quantum dots(QDs)in photocatalysis.Herein,the construction of a novel S-scheme heterojunction between cubic-phase CdS QDs and hollow nanotube In_(2)O_(3)is successfully achieved using an electrostatic self-assembly method.Under visible light irradiation,all CdS-In_(2)O_(3)composites exhibit higher hydrogen evolution efficiency compared to pure CdS QDs.Notably,the photocatalytic H_(2)evolution rate of the optimal CdS-7%In_(2)O_(3)composite is determined to be 2258.59μmol g^(−1)h^(−1),approximately 12.3 times higher than that of pure CdS.The cyclic test indicates that the CdS-In_(2)O_(3)composite maintains considerable activity even after 5 cycles,indicating its excellent stability.In situ X-ray photoelectron spectroscopy and density functional theory calculations confirm that carrier migration in CdS-In_(2)O_(3)composites adheres to a typical S-scheme heterojunction mechanism.Additionally,a series of characterizations demonstrate that the formation of S-scheme heterojunctions between In_(2)O_(3)and CdS inhibits charge recombination and accelerates the separation and migration of photogenerated carriers in the CdS QDs,thus achieving enhanced photocatalytic performance.This work elucidates the pivotal role of S-scheme heterojunctions in photocatalytic H_(2)production and offers novel insights into the construction of effective composite photocatalysts.
基金financially supported by the National Natural Science Foundation of China (No.52071146)Guangdong Provincial Natural Science Foundation (No.2023A1515010989)the Science and Technology Projects in Guangzhou (No.202201000008)。
文摘Water purification systems based on transition metal dichalcogenides face significant challenges,including lack of reactivity under dark conditions,scarcity of catalytically active sites,and rapid recombination of photogenerated charge carriers.Simultaneously increasing the number of active sites and improving charge separation efficiency has proven difficult.In this study,we present a novel approach combining molybdenum(Mo) monoatomic doping and size engineering to produce a series of Mo-ReS_(2) quantum dots(MR QDs) with controllable dimensions.High-resolution structural characterization,first-principle calculations,and piezo force microscopy reveal that Mo monoatomic doping enhances the lattice asymmetry,thereby improving the piezoelectric properties.The resulting piezoelectric polarization and the generated built-in electric field significantly improve charge separation efficiency,leading to optimized photocatalytic performance.Additionally,the doping strategy increases the number of active sites and improves the adsorption of intermediate radicals,substantially boosting photo-sterilization efficiency.Our results demonstrate the elimination of 99.95% of Escherichia coli and 100.00% of Staphylococcus aureus within 30 min.Furthermore,we developed a self-purification system simulating water drainage,utilizing low-frequency water streams to trigger the piezoelectric behavior of MR QDs,achieving piezoelectric synergistic photodegradation.This innovative approach provides a more environmentally friendly and economical method for water self-purification,paving the way for advanced water treatment technologies.
基金Project supported by the National Natural Science Foundation of China(22176054,22306060)China Postdoctoral Science Foundation(2022M721134)the Fundamental Research Funds for the Central Universities(2023MS060)。
文摘Imines play a pivotal role as multifunctional intermediates in pharmaceutical and biological applications,and their selective synthesis under mild conditions has attracted increasing interest.In this study,a covalent-organic frameworks(COFs)modified with CeO_(2)quantum dots(QDs)were prepared through a simple chemical reaction using LZU1 COFs and Ce(NO_(3))_(3)·6H_(2)O serving as precursors.The optimized5CeO_(2)QDs@LZU1 decorated with about 3.9 wt%CeO_(2)QDs demonstrates excellent performance in the photocatalytic selective oxidative of amines in visible light conditions,achieving nearly 100%benzylamine conversion and over 99%imine selectivity within 6 h,which is significantly superior to that of pure LZU1 and CeO_(2).The remarkable enhancement in activity is mainly attributed to the fact that the interaction between CeO_(2)QDs and LZU1 COF in 5CeO_(2)QDs@LZU1 improves the visible light response and concurrently promotes the separation efficiency of photogenerated e-and h+pairs.Broad substrate scope also provides a prospect for the industrial synthesis of various imines.Our findings not only expand the application range of COFs by incorporating QDs but also lay the groundwork for their further rational design and optimization.
基金support from the Natural Science Foundation of Shanghai(No.23ZR1423800)Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University。
文摘TiO_(2)has been widely studied as one of the most promising anode materials for lithium-ion batteries(LIBs)due to good structural stability and small volume changes.However,its applications are still greatly affected by its poor electrical conductivity.In this work,ultrasmall TiO_(2)quantum dots(QDs)are firmly grown onto 2D Ti_(3)C_(2)T_(x)nanosheets(A-TiO_(2)/Ti_(3)C_(2)T_(x)),benefiting from the positive regulation of(3-aminopropyl)triethoxysilane(APTES).Interestingly,SiO_(2)nanoparticles produced by the hydrolysis of APTES can strengthen the strong coupling of TiO_(2)QDs with Ti_(3)C_(2)T_(x),thereby enhancing the structural integrity of the composite.As expected,the A-TiO_(2)/Ti_(3)C_(2)T_(x)composite demonstrates an exceptional lithium storage performance,achieving a high capacity of 425.4 m Ah/g for 400 cycles at 0.1 A/g,and an outstanding long-term cycling stability.In-situ electrochemical impedance spectroscopy and theoretical analysis unconver that the superior lithium storage performance is attributed to its unique heterostructure and in-situ N doping derived from APTES,which not only reduces the Li^(+)adsorption energy,but also gives the fast charge transfer dynamics.
基金support from the Natural Science Foundation of Shanghai(23ZR1423800),Shuguang Program supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(18SG35)Open Research Fund of Shanghai Key Laboratory of Green Chemistry and Chemical Processes(East China Normal University)Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University.
文摘TiNb_(2)O_(7)has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries.However,limited by the slow electron/ion transport kinetics,and insufficient active sites in the bulk structure,the TiNb_(2)O_(7)electrode still suffers from unsatisfactory lithium storage performance.Herein,we demonstrate a spatially confined strategy toward a novel TiNb_(2)O_(7)-NMC/MXene composite through a triblock copolymer-directed one-pot solvothermal route,where TiNb_(2)O_(7)quantum dots with a particle size of 2-3 nm are evenly embedded into N-doped mesoporous carbon(NMC)and Ti_(3)C_(2)T_(X)MXene.Impressively,the as-prepared TiNb_(2)O_(7)-NMC/MXene anode exhibits a high reversible capacity(486.2 mAh g^(-1)at 0.1 A g^(-1)after 100 cycles)and long cycle lifespan(363.4 mAh g^(-1)at ss1 A g^(-1)after 500 cycles).Both experimental and theorical results further demonstrate that such a superior lithium storage performance is mainly ascribed to the synergistic effect among 0D TiNb_(2)O_(7)quantum dots,2D Ti_(3)C_(2)T_(X)MXene nanosheets,and N-doped mesoporous carbon.The strategy presented also opens up new horizon for space-confined preparation of high-performance electrode materials.
基金supported by the National Key Research and Development Program of China“New Energy Project for Electric Vehicle”(2016YFB0100204)the National Natural Science Foundation of China(Nos.51772030,21805011,51572011,51802012)+2 种基金the Joint Funds of the National Natural Science Foundation of China(U1564206)Beijing Key Research and Development Plan(Z181100004518001)China Postdoctoral Science Foundation(Nos.2017M620637,2018M643697,2019T120930).
文摘MXenes,a new family of two-dimensional(2D)materials with excellent electronic conductivity and hydrophilicity,have shown distinctive advantages as a highly conductive matrix material for lithium-ion battery anodes.Herein,a facile electrostatic self-assembly of SnO2 quantum dots(QDs)on Ti3C2Tx MXene sheets is proposed.The as-prepared SnO2/MXene hybrids have a unique 0D-2D structure,in which the 0D SnO2 QDs(~4.7 nm)are uniformly distributed over 2D Ti3C2Tx MXene sheets with controllable loading amount.The SnO2 QDs serve as a high capacity provider and the“spacer”to prevent the MXene sheets from restacking;the highly conductive Ti3C2Tx MXene can not only provide efficient pathways for fast transport of electrons and Li ions,but also buffer the volume change of SnO2 during lithiation/delithiation by confining SnO2 QDs between the MXene nanosheets.Therefore,the 0D-2D SnO2 QDs/MXene hybrids deliver superior lithium storage properties with high capacity(887.4 mAh g?1 at 50 mA g?1),stable cycle performance(659.8 mAh g?1 at 100 mA g?1 after 100 cycles with a capacity retention of 91%)and excellent rate performance(364 mAh g?1 at 3 A g?1),making it a promising anode material for lithium-ion batteries.
基金supported by the National Natural Science Foundation of China(51602207)the Doctoral Scientific Research Foundation of Liaoning Province(20170520011)+3 种基金the Program for Liaoning Excellent Talents in Universities(LR2017074)the Open Project Program of the State Key Laboratory of Photocatalysis on Energy and Environment(SKLPEE-201810)Fuzhou University,the Scientific Research Project of the Educational Department of Liaoning Province(LQN201712)Shenyang Excellent Talents in Universities(RC180211)~~
文摘Photocatalytic water splitting is a promising method for hydrogen production.Numerous efficient photocatalysts have been synthesized and utilized.However,photocatalysts without a noble metal as the co-catalyst have been rarely reported.Herein,a CoP co-catalyst-modified graphitic-C3N4(g-C3N4/CoP)is investigated for photocatalytic water splitting to produce H2.The g-C3N4/CoP composite is synthesized in two steps.The first step is related to thermal decomposition,and the second step involves an electroless plating technique.The photocatalytic activity for hydrogen evolution reactions of g-C3N4 is distinctly increased by loading the appropriate amount of CoP quantum dots(QDs).Among the as-synthesized samples,the optimized one(g-C3N4/CoP-4%)shows exceptional photocatalytic activity as compared with pristine g-C3N4,generating H2 at a rate of 936μmol g^-1 h^-1,even higher than that of g-C3N4 with 4 wt%Pt(665μmol g^-1 h^-1).The UV-visible and optical absorption behavior confirms that g-C3N4 has an absorption edge at 451 nm,but after being composited with CoP,g-C3N4/CoP-4%has an absorption edge at 497 nm.Furthermore,photoluminescence and photocurrent measurements confirm that loading CoP QDs to pristine g-C3N4 not only enhances the charge separation,but also improves the transfer of photogenerated e--h+pairs,thus improving the photocatalytic performance of the catalyst to generate H2.This work demonstrates a feasible strategy for the synthesis of highly efficient metal phosphide-loaded g-C3N4 for hydrogen generation.
文摘H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness.As a sustainable H2-generation method,photocatalytic H2 production by water splitting has attracted much interest.Here,oil-soluble ZnxCd1-xS quantum dot(ZCS QD)with a uniform particle size distribution were prepared by a hot-injection method.However,no photocatalytic H2-production activity was observed for the oil-soluble ZCS QD due to its hydrophobicity.Thus,the oil-soluble ZCS QD was converted into a water-soluble ZCS QD by a ligand-exchange method.The water-soluble ZCS QD exhibited excellent photocatalytic H2-production performance in the presence of glycerin and Ni^2+,with an apparent quantum efficiency of 15.9%under irradiation of 420 nm light.Further,the photocatalytic H2-generation activity of the ZCS QD was~10.7 times higher than that of the ZnxCd1-xS relative samples prepared by the conventional co-precipitation method.This work will inspire the design and fabrication of other semiconductor QD photocatalysts because QD exhibits excellent separation efficiency for photogenerated electron-hole pairs due to its small crystallite size.
基金financially supported by the National Natural Science Foundation of China(U1510126,21676115)the Natural Science Foundation of Jiangsu Provincial(BK20180884)~~
文摘Herein,we report a novel ternary material comprised of Ag nanoparticles and carbon quantum dots(CDs),which are co-loaded using 2D Bi4Ti3O12(BIT)sheets.In this system,Ag can be applied as excited electron-hole pairs in the Bi4Ti3O12 by transferring the plasmonic energy from the metal to the semiconductor.The surface plasmon resonance of Ag can promote the electron transfer properties of the CDs,thereby improving the separation efficiency of the electron-hole pairs.Meanwhile,the CDs can act as an electron buffer to decrease the recombination rate of the electron hole.Moreover,CDs are prepared using a biomaterial,which can provide a chemical group to enhance the electron transfer and connection.The synergistic effects of CDs,Ag,and BIT enable the design of a photocatalytic application with a remarkably improved efficiency and operational stability.
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Project supported by the National Natural Science Foundation of China(51872207,51672192)。
文摘In this work,Eu^(3+)-doped CsPbCl_(2)Br_(1) in borosilicate glass was successfully synthesized by the melt quenching annealing technique and crystallization method.This work reports a novel Eu^(3+)-doped CsPbCl_(2)Br_(1) perovskite quantum dots(QDs)glass with high sensitivity for optical temperature sensing.The relation of fluorescence intensity ratio(FIR)with the temperature was studied in the temperature range of 80-440 K.Notably,the maximum absolute temperature sensitivity(Sa)and relative temperature sensitivity(Sr)of Eu^(3+)-doped CsPbCl_(2)Br_(1) perovskite QDs glass can reach as high as 0.0315 K-1 and3.097%/K,respectively.Meanwhile,Eu^(3+)-doped CsPbCl_(2)Br_(1) QDs glass demonstrates good water resistance,excellent thermal and cold cycling stability performance,The Eu^(3+)-doped QDs glass materials can bring inspiration to the future exploration of rare earth ion-doped QDs glass material on the application of optical temperature sensing in the future.
基金financially supported by the National Natural Science Foundation of China (Nos.62071300 and51702212)the Science and Technology Commission of Shanghai Municipality (Nos.18511110600,19ZR1435200,and 20490761100)+2 种基金the Innovation Program of Shanghai Municipal Education Commission (No.2019-01-07-00-07-E00015)the Program of Shanghai Academic/Technology Research Leader (No.19XD1422900)the Chenguang Scholar Project of Shanghai Education Commission (No. 19CG52) and Cross-Program of Medical & Engineering。
文摘Formaldehyde(HCHO) is widely known as an indoor air pollutant,and the monitoring of the gas has significant importance.However,most HCHO sensing materials do not have low detection limits and operate at high temperatures.Herein,two-dimensional(2D) mesoporous ultrathin SnO_(2) modified with nitrogen-doped graphene quantum dots(N-GQDs) was synthesized.The N-GQDs/SnO_(2) nanocomposite demonstrated high efficiency for HCHO detection.With the addition of 1.00 wt%N-GQDs,the response(Ra/Rg) of SnO_(2) gas sensor increased from 120 to 361 at 60℃ for the detection of 10×10^(-6) HCHO.In addition,the corresponding detection limit was as low as 10×10^(-9).Moreover,the sensor exhibited excellent selectivity and stability for the detection of HCHO.The enhanced sensing performance was attributed to both the large specific surface area of SnO_(2) and electron regulation of N-GQDs.Therefore,this study presents a novel HCHO sensor,and it expands the research and application potential of GQDs nanocomposites.
基金funded by Jiangsu Province Six Talent Peaks Project(No.2014-XCL-013)Jiangsu Industrial-academic-research Prospective Joint Project(No.BY2016069-02)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions and Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(No.PPZY2015B112)。
文摘The 2 D nanomaterials have achieved the superlubrication property whatever in solid or liquid lubrication in recent years.However,whether or not the nanosheets can stably disperse in oils and smoothly enter into the asperity of friction pairs is crucial for exerting the function of antifriction.The structure of 2 D QDs is desirable for addressing these issues due to its smaller 3 D size.In this study,we developed a facile preparation process for WS_(2) QDs with uniform 2 nm size from nanosheets via hydrothermal-assisted grinding approach.The structure of the as-obtained WS_(2) QDs was determined by a series of characterizations.The results showed that the as-obtained WS_(2) QDs exhibited the typical spectrum features of nanosized quantum dot.The results of the tribological performance in grease verified that the average friction coefficient(ACOFs) and wear volume(AWVs) were decreased by 7.89% and 63.90%relative to grease,respectively,exhibiting a preferable friction reducing and wear resistance.
基金National Natural Science Foundation of China(Grant No.21674011,21404008)Beijing Municipal Natural Science Foundation(Grant No.2172040)+1 种基金Beijing Organization department outstanding talented person project(2013D009006000001)the Fundamental Research Funds for the Central Universities(FRF-GF-17-B11)。
文摘As a novel zero-dimensional(0D)material,metal carbides and/or carbonitrides(MXenes)quantum dots(MQDs)show unique photoluminescence properties and excellent biocompatibility.However,due to the limited synthesis methods and research to date,many new features have yet to be uncovered.Here,to explore their new properties and expand biological applications,chlorine and nitrogen co-doped Ti_(3)C_(2)MXene quantum dots(Cl,N-Ti_(3)C_(2)MQDs)were designed and synthesized,and their hydroxyl radical scavenging properties were investigated for the first time,revealing outstanding performance.Cl,N-Ti_(3)C_(2)MQDs was directly stripped from bulk Ti_(3)Al C_(2)by electrochemical etching,while N and Cl are successfully introduced to carbon skeleton and Ti boundaries in the etching process by electrochemical reactions between selected electrolytes and Ti_(3)C_(2)skeleton,respectively.The obtained Cl,N-Ti_(3)C_(2)MQDs exhibit large surface-to-volume ratio due to small particle size(ca.3.45 nm)and excellent higher scavenging activity(93.3%)and lower usage(12.5μg/m L)towards hydroxyl radicals than the previous reported graphene-based nanoparticles.The underlying mechanism of scavenging activity was also studied based on the reduction experiment with potassium permanganate(KMnO_(4)).The reducing ability of the intrinsic Ti_(3)C_(2)structure and electron donation of double dopants are the main contributors to the outstanding scavenging activity.
基金This work is supported by National Natural Science Foundation of China(No.92163135,11904098,51972105,U19A2090 and 62090035)Hunan Provincial Natural Science Foundation of China(No.2019JJ30004)+1 种基金Hunan International Innovation Cooperation Platform(No.2018WK4004)Key Program of Science and Technology Department of Hunan Province(Nos.2019XK2001,2020XK2001).
文摘Mix-dimensional van der Waals heterostructures(vdWHs)have inspired worldwide interests and efforts in the field of ad-vanced electronics and optoelectronics.The fundamental understanding of interfacial charge transfer is of vital import-ance for guiding the design of functional optoelectronic applications.In this work,type-Ⅱ0D-2D CdSe/ZnS quantum dots/MoS_(2)vdWHs are designed to study the light-triggered interfacial charge behaviors and enhanced optoelectronic performances.From spectral measurements in both steady and transient states,the phenomena of suppressed photolu-minescence(PL)emissions,shifted Raman signals and changed PL lifetimes provide strong evidences of efficient charge transfer at the 0D-2D interface.A series of spectral evolutions of heterostructures with various QDs overlapping concentrations at different laser powers are analyzed in details,which clarifies the dynamic competition between exciton and trion during an efficient doping of 3.9×10^(13)cm^(−2).The enhanced photoresponses(1.57×10^(4)A·W^(-1))and detectivities(2.86×10^(11)Jones)in 0D/2D phototransistors further demonstrate that the light-induced charge transfer is still a feasible way to optimize the performance of optoelectronic devices.These results are expected to inspire the basic understand-ing of interfacial physics at 0D/2D interfaces,and shed the light on promoting the development of mixed-dimensional op-toelectronic devices in the near future.
基金financial supports from National Natural Science Foundation of China (51802269 and 21773138)Chongqing Natural Science Foundation (cstc2018jcyjAX0624)+1 种基金Fundamental Research Funds for the Central Universities (XDJK2019AA002)Venture & Innovation Support Program for Chongqing overseas returnees (cx2018027)。
文摘Smartcombination of manifold carbonaceous materials with admirable functionalities(like full of pores/functional groups,high specific surface area) is still a mainstream/preferential way to address knotty issues of polysulfides dissolution/shuttling and poor electrical conductivity for S-based cathodes.However,extensive use of conductive carbon fillers in cell designs/technology would induce electrolytic overconsumption and thereby shelve high-energy-density promise of Li-S cells.To cut down carbon usage,we propose the incorporation of multi-functionalized NiFe2O4 quantum dots(QDs) as affordable additive substitutes.The total carbon content can be greatly curtailed from 26%(in traditional S/C cathodes) to a low/commercial mass ratio(~5%).Particularly,note that NiFe2O4 QDs additives own superb chemisorption interactions with soluble Li2Sn molecules and proper catalytic features facilitating polysulfide phase conversions and can also strengthen charge-transfer capability/redox kinetics of overall cathode systems.Benefiting from these intrinsic properties,such hybrid cathodes demonstrate prominent rate behaviors(decent capacity retention with ~526 mAh g^-1 even at 5 A g^-1) and stable cyclic performance in LiNO3-free electrolytes(only ~0.08% capacity decay per cycle in 500 cycles at 0.2 A g^-1).This work may arouse tremendous research interest in seeking other alternative QDs and offer an economical/more applicable methodology to construct low-carbon-content electrodes for practical usage.
基金financial support from the Shuguang Program supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.18SG035)Shanghai Pujiang Program(No.17PJD015)。
文摘It has been demonstrated that the conductivity and electrochemical properties of TiO2 nanomate rials can be significantly improved by an incorporation of carbon additives.In the study,we develop a novel Ndoped TiO2 mesoporous nanostructure via the addition of carbon quantum dots(CQDs)solution following a scalable hydrothermal process.The as-made TiO2 product shows well-defined morphology,high conductivity,large surface area,and abundant mesopores.When evaluated as anodes for sodiumion batteries,the CQDs@TiO2 product annealed at 500℃exhibits a superior sodium storage capability.It delivers a high reversible capacity of 168.8 mAh/g at 100 mA/g over 500 cycles and long cycling stability.The remarkable performance of CQDs@TiO2 mainly arises from the large surface area and mesoporous architecture constructed by ultrathin TiO2 nanosheets,as well as the full coope ration between CQDs and TiO2.
基金supported by the National Natural Science Foundation of China (Nos.51902266 and 22002185)the Fundamental Research Funds for the Central Universities (Nos.310201QD0410 and 3102019ZD0403)+2 种基金the Natural Science Foundation of Beijing (No.2204100)Natural Science Foundation of Shaanxi (No.2020JQ-143)supported by the Research Fund of the State Key Laboratory of Solidification Processing (NPU),China (No.2019-TS-12)。
文摘Fabrication of well-designed heterojunctions is an extraordinarily attractive pathway for boosting the photocatalytic activity toward CO_(2) photoreduction.Herein,a novel kind of na nosheet-based intercalation hybrid coupled with CdSe quantum dots(QDs) was successfully fabricated by a facile solvothermal method and served as photocatalyst for full-spectrum-light-driven CO_(2) reduction.Ultra-small CdSe QDs were rationally in-situ introduced and coupled with lamellar ZnSe-intercalation hybrid nanosheet,resulting in the formation of CdSe Q.Ds/ZnSe hybrid heterojunction.Significantly,the concentration of Cd^(2+) could change directly the crystallinity and micromorphology of ZnSe intercalation hybrid,which in turn would impact on the photocatalysis activity.The optimized CdSe QDs/ZnSe hybrid-5 composite demonstrated a considerable CO yield rate of the 25.6 μmol g^(-1) h^(-1) without any additional cocatalysts or sacrificial agents assisting,making it one of the best reported performance toward CO_(2) photoreduction under full-spectrum light.The elevated CO_(2) photoreduction activity could be attributed to the special surface heterojunction,leading to improving the ability of light absorption and promoting the separation/transfer of photogenerated carriers.This present study developed a new strategy for designing inorganic-organic heterojunctions with enhanced photocatalyst for CO_(2) photoreduction and provided an available way to simultaneously mitigate the greenhouse effect and alleviate energy shortage pressure.
基金supported by National Natural Science Foundation of China(51672113)Six Talent Peaks Project in Jiangsu Province(2015-XCL-026)+3 种基金Natural Science Foundation of Jiangsu Province(BK20171299)State Key Laboratory of Photocatalysis on Energy and Environment(SKLPEE-KF201705),Fuzhou UniversityState Key Laboratory of Advanced Technology for Materials Synthesis and Processing(2016-KF-10),Wuhan University of Technologythe Qing Lan Project Foundation of Jiangsu Province~~
文摘Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐dimensional(2D)g‐C3N4nanoplates and zero‐dimensional(0D)MoS2quantum dots(QDs)was prepared through the combination of a hydrothermal process and microemulsion preparation.The morphologies,structures,and optical properties of the as‐prepared photocatalysts were characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,atomic force microscopy,transmission electron microscopy,and UV‐vis diffuse reflectance spectroscopy.In addition,the photocatalytic performances of the prepared2D/0D hybrid composites were evaluated based on the photodegradation of rhodamine B under visible‐light irradiation.The results demonstrated that the introduction of MoS2QDs to g‐C3N4greatly enhanced the photocatalytic efficiency.For the optimum7%MoS2QD/g‐C3N4photocatalyst,the degradation rate constant was8.8times greater than that of pure g‐C3N4under visible‐light irradiation.Photocurrent and electrochemical impedance spectroscopy results further demonstrated that the MoS2QD/g‐C3N4composites exhibited higher photocurrent density and lower chargetransfer resistance than those of the pure g‐C3N4or MoS2QDs.Active species trapping,terephthalic acid photoluminescence,and nitro blue tetrazolium transformation experiments were performed to investigate the evolution of reactive oxygen species,including hydroxyl radicals and superoxide radicals.The possible enhanced photocatalytic mechanism was attributed to a direct Z‐scheme system,which not only can increase the separation efficiency of photogenerated electron‐hole pairs but also possesses excellent oxidation and reduction ability for high photocatalytic performances.This work provides an effective synthesis approach and insight to help develop other C3N4‐based direct Z‐scheme photocatalytic systems for environmental purification and energy conversion.
文摘Depositing a cocatalyst has proven to be an important strategy for improving the photoelectrochemical(PEC)water-splitting efficiency of photoanodes.In this study,Ni(OH)2 quantum dots(Ni(OH)2 QDs)were deposited in situ onto anα-Fe_(2)O_(3)photoanode via a chelation-mediated hydrolysis method.The photocurrent density of the Ni(OH)2 QDs/α-Fe_(2)O_(3)photoanode reached 1.93 mA·cm^(−2)at 1.23 V vs.RHE,which is 3.5 times that ofα-Fe_(2)O_(3),and an onset potential with a negative shift of ca.100 mV was achieved.More importantly,the Ni(OH)2 QDs exhibited excellent stability in maintaining PEC water oxidation at a high current density,which is attributed to the ultra-small crystalline size,allowing for the rapid acceptance of holes fromα-Fe_(2)O_(3)to Ni(OH)_(2)QDs,formation of active sites for water oxidation,and hole transfer from the active sites to water molecules.Further(photo)electrochemical analysis suggests that Ni(OH)_(2)QDs not only provide maximal active sites for water oxidation but also suppress charge recombination by passivating the surface states ofα-Fe_(2)O_(3),thereby significantly enhancing the water oxidation kinetics over theα-Fe_(2)O_(3)surface.
