CuS-C50,the cathode materials for magnesium ion batteries,was synthesized by adding the surfactant cetyltrimethyl ammonium bromide(CTAB)and adjusting the percentage of ethylene glycol to 50vol%in hydrothermal synthesi...CuS-C50,the cathode materials for magnesium ion batteries,was synthesized by adding the surfactant cetyltrimethyl ammonium bromide(CTAB)and adjusting the percentage of ethylene glycol to 50vol%in hydrothermal synthesis process.Results show that CuS-C50 has the complete nanoflower structure.In aluminum chloride-pentamethylcydopentodiene/tetrahydrofuran(APC/THF)electrolyte,the CuS-C50 exhibits a high specific capacity of 331.19 mAh/g when the current density is 50 mA/g and still keeps a specific capacity of 136.92 mAh/g over 50 cycles when the current density is 200 mA/g.Results of morphology characterizations indicate that the complete nanoflower structure can provide more active sites and reduce the barriers for Mg^(2+)movement,eventually improving the charge and discharge performance of the CuS cathode materials for magnesium ion batteries.展开更多
The rapid corrosion rate and limited biological functionality still pose challenges for magnesium(Mg)-based implants in the treatment of complicated bone-related diseases in clinic.Herein,a multifunctional biodegradab...The rapid corrosion rate and limited biological functionality still pose challenges for magnesium(Mg)-based implants in the treatment of complicated bone-related diseases in clinic.Herein,a multifunctional biodegradable curcumin(herbal medicine)-ferrum(Cur-Fe)nanoflower was self-assembled on plasma electrolytic oxidation(PEO)-treated Mg alloy via a facile immersion process to realize differential biological function for anti-bacteria/tumor and bone regeneration.The results indicated that Cur-Fe nanoflower coating can promote protein adsorption,cell adhesion and proliferation,exhibiting excellent biocompatibility.The Cur-Fe nanoflower coating exhibits unique degradation characteristics,as curcumin gradually decomposes into ferulic acid,aromatic aldehyde and other antibacterial substances,and the coating spontaneously converts into FeOOH nanosheets,ensuring the corrosion resistance of Mg-based implants.Moreover,Cur-Fe coating exhibits remarkable narrow gap semiconductor characteristics,which can generate reactive oxygen species(ROS)and demonstrated excellent antibacterial effect under simulated sunlight(SSL)irradiation.Meanwhile,under NIR irradiation,Cur-Fe coating showed excellent chemotherapy/photodynamic/photothermal synergetic antitumor properties in vitro and in vivo due to the introduction of curcumin,and photocatalysis and photothermal conversion properties of coating.Furthermore,Cur-Fe nanoflower coating demonstrated great osteogenesis activity in vitro and in vivo due to unique micro/nano structure,surface chemical bond,and the release of Mg and Fe ions.展开更多
The catalytic direct synthesis of dimethyl carbonate(DMC)from CO_(2)and methanol is a crucial approach to utilizing CO_(2)and producing high-value chemicals.However,the high stability of the CO_(2)molecule imposes the...The catalytic direct synthesis of dimethyl carbonate(DMC)from CO_(2)and methanol is a crucial approach to utilizing CO_(2)and producing high-value chemicals.However,the high stability of the CO_(2)molecule imposes thermodynamic limitations on this reaction pathway,along with challenges related to insufficient catalyst activity and stability.Currently,solutions primarily focus on developing efficient catalyst.Herein,La-doped CeO_(2)nanoflower catalysts(La_(x)CeO_(2))were synthesized via hydrothermal method.Characterization reveals that La doping optimizes the pore structure and enriched oxygen vacancies,thereby enhancing catalytic performance.Notably,La_(0.1)CeO_(2)exhibits the largest pore size and highest oxygen vacancy content,achieving a remarkable DMC productivity of 9.42 mmol/g under 140℃,4 MPa of CO_(2),and 3 h of reactio n,surpassing pure CeO_(2)nano flowers.Based on experimental findings and in-situ diffuse infrared Fourier transform analysis,a plausible reaction pathway was proposed.This work underscores the potential of La_(x)CeO_(2)nano flowers as efficient catalysts for sustainable CO_(2)conversion to DMC.展开更多
Despite advances in photocatalytic half-reduction reactions,challenges remain in effectively utilizing electron-hole pairs in concurrent redox processes.The present study involved the construction of a p-n junction Co...Despite advances in photocatalytic half-reduction reactions,challenges remain in effectively utilizing electron-hole pairs in concurrent redox processes.The present study involved the construction of a p-n junction Co_(3)O_(4)/Zn_(3)In_(2)S_(6)(CoZ)hybrid with a complementary band edge potential.The photocatalyst formed by the 2D assembled-nanostructure portrayed an optimal yield of 13.8(H_(2))and 13.1(benzaldehyde)mmol g^(-1)h^(-1)when exposed to light(λ>420 nm),surpassing 1%Pt-added ZIS(12.4(H_(2))and 10.71(benzaldehyde)mmol g^(-1)h^(-1)).Around 95%of the electron-hole utilization rate was achieved.The solar-to-hydrogen(STH)and apparent quantum yield(AQY)values of 0.466%and 4.96%(420nm)achieved by this system in the absence of sacrificial agents exceeded those of previous works.The exceptional performance was mostly ascribed to the synergistic development of adjoining p-n heterojunctions and the built-in electric field for effective charge separation.Moreover,scavenger studies elucidated the intricate mechanistic enigma of the dual-redox process,in which benzaldehyde was produced via O-H activation and subsequent C-H cleavage of benzyl alcohol over CoZ hybrids.Furthermore,the widespread use of the optimal 1-CoZ composites was confirmed in multiple photoredox systems.This work presents an innovative perspective on the construction of dual-functioning p-n heterojunctions for practical photoredox applications.展开更多
Traditional photo-electcatalyst structures of small noble metal nanoparticles assembling into large-scale photoactive semiconductors still suffer from agglomeration of noble metal nanoparticles,insufficient charge tra...Traditional photo-electcatalyst structures of small noble metal nanoparticles assembling into large-scale photoactive semiconductors still suffer from agglomeration of noble metal nanoparticles,insufficient charge transfer,undesirable photoresponse ability that restricted the photo-electrocatalytic performance.To this end,a novel design strategy is proposed in this work,namely integrating small-scale photoactive materials(doped graphene quantum dots,S,N-GQDs)with large-sized noble metal(Pd P)nanoflowers to form novel photo-electrocatalysts for high-efficient alcohol oxidation reaction.As expected,superior electrocatalytic performance of Pd P/S,N-GQDs for ethylene glycol oxidation is acquired,thanks to the nanoflower structure with larger specific surface area and abundant active sites.Furthermore,nonmetal P are demonstrated,especially optimizing the adsorption strength,enhancing the interfacial contact,reducing metal agglomeration,ensuring uniform and efficient doping of S,N-GQDs,and ultimately significantly boost the catalytic activity of photo-electrocatalysts.展开更多
This study ingeniously synthesized a novel CdS/NiS hollow nanoflower sphere(HNS)using a one-step method to enhance photocatalytic hydrogen production activity.Compared to conventional preparation methods,this approach...This study ingeniously synthesized a novel CdS/NiS hollow nanoflower sphere(HNS)using a one-step method to enhance photocatalytic hydrogen production activity.Compared to conventional preparation methods,this approach features seamlessly interfaced contact that facilitates efficient electron transfer across the interface.The internal hollow structure allows for multiple light reflections,maximizing light absorption,while the exterior shell and inner surfaces simultaneously offer active sites for reactions.The modification with non-noble metal NiS enables the extraction of electrons from CdS to the NiS surface,achieving rapid charge separation.Furthermore,adsorption-free energy calculations reveal that the NiS surface is more conducive to photocatalytic hydrogen generation,providing additional reaction active sites.The results demonstrate a hydrogen production rate of 2.18 mmol g^(-1)h^(-1)for CdS/NiS HNS,which is 9.48 times greater than that of pristine CdS.This work presents a novel approach for synthesizing seamlessly interfaced contacts between photocatalysts and cocatalysts,offering new insight into efficient one-step synthesis for enhanced photocatalytic performance.展开更多
In this work Gd/La@ZnO nanoflower photocatalyst was successfully synthesized by a co-precipitation method and applied for rhodamine B(Rh B)and tetracycline(TCN)degradation under direct sunlight irradiation.The doping ...In this work Gd/La@ZnO nanoflower photocatalyst was successfully synthesized by a co-precipitation method and applied for rhodamine B(Rh B)and tetracycline(TCN)degradation under direct sunlight irradiation.The doping of rare earth elements extends the optical absorption wavelength of ZnO from UV region(390 nm)to visible-light region(401 nm).In addition,the co-doped ZnO nanoflower exhibits a lower charge recombination efficiency which was confirmed by photoluminescence emission analysis.Moreover,the co-doped ZnO nanoflower exhibits the maximum degradation efficiency of 91%for Rh B and 74%for TCN under sunlight irradiation.The calculated synergistic index of co-doped ZnO is higher than that of the pure ZnO.Reactive radicals’production was confirmed by terephthalic acid(TA)and nitro-blue tetrazolium(NBT)tests.The holes and hydroxyl(·OH)radicals play the major role in degradation reaction and it was confirmed by scavenger’s test.Moreover,the recycling test confirms the stability of the photocatalyst.展开更多
Vertical MoS2nanosheets were controllably patterned onto graphene as nanoflowers through a two-step hydrothermal method. The interconnected network and intimate contact between MoS2nanosheets and graphene by vertical ...Vertical MoS2nanosheets were controllably patterned onto graphene as nanoflowers through a two-step hydrothermal method. The interconnected network and intimate contact between MoS2nanosheets and graphene by vertical channels enabled a high mechanical integrity of electrode and cycling stability. In particular, MoS2/graphene nanoflowers anode delivered an ultrahigh specific capacity of 901.8 mA·h/g after 700 stable cycles at 1000 mA/g and a corresponding capacity retention as 98.9% from the second cycle onwards.展开更多
A new amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase at the glassy carbon electrode modified with zinc oxide nanoflowers produced by electrodeposition onto mul...A new amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase at the glassy carbon electrode modified with zinc oxide nanoflowers produced by electrodeposition onto multi-walled carbon nanotubes （MWNTs） film. The morphology of the MWNTs/nano-ZnO electrode has been investigated by scanning electron microscopy （SEM）, and the electrochemical performance of the electrode has also been studied by amperometric method. The resulting electrode offered an excellent detection for hydrogen peroxide at -0.11 V with a linear response range of 9.9×10^-7 to 2.9×10^-3 mol/L with a correlation coefficient of 0.991, and response time 〈5 s. The biosensor displays rapid response and expanded linear response range, and excellent stability.展开更多
A series of TiO2 with different crystal phases and morphologies was synthesized via a facile hydrothermal process using titanium nbutoxide and concentrated hydrochloric acid as raw materials. The photocatalytic activi...A series of TiO2 with different crystal phases and morphologies was synthesized via a facile hydrothermal process using titanium nbutoxide and concentrated hydrochloric acid as raw materials. The photocatalytic activity of the samples was evaluated by degradation of Methyl Orange in aqueous solution under UV-Visible light irradiation. On the basis of detailed analysis of the characterizing results of high-resolution transmission electron microscopy, X-ray powder diffraction measurements, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller measurement, it was concluded that the photo-activity of the catalyst is related directly to the 3D morphology and the crystal phase composition. An excellent catalyst should have both a futile 3D flower-like structure and anatase granulous particles. The 3D flower-like structure could enhance light harvesting, as well as the transfer of reactant molecules from bulk solution to the reactive sites on TiO2. In addition, the optimum anatase/rutile phase ratio was found to be 80：20, which is beneficial to the effective separation of the photogenerated electron-hole pairs.展开更多
Alloy and small size nanostructure s are favorable to catalytical performance,but not to surface-enhanced Raman spectroscopy(SERS) applications.Integrating SERS and catalytic activity into the nanocrystals with both a...Alloy and small size nanostructure s are favorable to catalytical performance,but not to surface-enhanced Raman spectroscopy(SERS) applications.Integrating SERS and catalytic activity into the nanocrystals with both alloy and small size structures is of great interest in fabrication of SERS platform to in situ monitor catalytical reaction.Herein,we report a facile method to synthesize Au@AgPd trimetallic nanoflowers(Au@AgPd NFs) with both SERS and catalytic activities,through simultaneous selective growth of Ag and Pd on Au core to form highly-branched alloy shell.These nanocrystals have the properties of small sizes,defects abundance,and highly-dispersed alloy shell which offer superior catalytic activity,while the merits of monodisperse,excellent stability,and highly-branched shell and core/alloy-shell structure promise the enhanced SERS activity.We further studied their growth mechanisms,and found that the ratio of Ag to Pd,sizes of Au core,and surfactant cetyltrimethylammonium bromide together determine this special structure.Using this as-synthesized nanocrystals,a monolayer bifunctional platform with both SERS and catalytical activity was fabricated through selfassembly at air/water interface,and applied to in situ SERS monitoring the reaction process of Pdcatalyzed hydrogenation of 4-nitrothiophenol to 4-aminothio p henol.展开更多
Bi-functional electrocatalysts for acid overall water splitting reactions are crucial but still challenging to the development of proton exchange membrane water electrolysis.Herein,an efficient bi-functional catalyst ...Bi-functional electrocatalysts for acid overall water splitting reactions are crucial but still challenging to the development of proton exchange membrane water electrolysis.Herein,an efficient bi-functional catalyst of Ir/MoS_(2) nanoflowers(Ir/MoS_(2) NFs) catalyst was reported for acidic water electrolysis which can be constructed by coupling three-dimensionally interconnected MoS_(2) NFs with ultrafine Ir nanoparticles.A more suitable adsorption ability for the H* and *OOH intermediates was revealed,where the Ir sites were proposed as the main active center and MoS_(2) promoted the charge relocation to electronically modify the interfacial structure.The significant interfacial charge redistribution between the MoS_(2) NFs and the Ir active sites synergistically induced excellent catalytic activity and stability for the water electrolysis reaction.Specifically,the catalyst required overpotentials of 270 and 35 mV to reach a kinetic current density of 10 mA cm^(-2)for OER and HER,respectively,loading on the glass carbon electrode,with high catalytic kinetics,stability,and catalytic efficiency.A two-electrode system constructed by Ir/MoS_(2) NFs drove 10 mA cm^(-2)at a cell voltage of 1.55 V,about 70 mV lower than that of the commercial Pt/C||IrO_(2) system.In addition,partial surface oxidation of Ir nanoparticles to generate high-valent Ir species was also found significant to accelerate OER.The enhanced catalytic performance was attributed to the strong metal-support interaction in the Ir/MoS_(2) NFs catalyst system that changed the electronic structure of Ir metal and promoted the synergistic catalytic effect between Ir and MoS_(2) NFs.The work presented a novel platform of Ir-catalyst for proton exchange membrane water electrolysis.展开更多
In this study,we report the synthesis of novel palladium nanoflowers(Pd NFs)on amino-functionalized fullerene(C60-NH2)by hydrothermal self-assembly growth using ethylenediamine(EA)as a functional reagent.The successfu...In this study,we report the synthesis of novel palladium nanoflowers(Pd NFs)on amino-functionalized fullerene(C60-NH2)by hydrothermal self-assembly growth using ethylenediamine(EA)as a functional reagent.The successful formation of Pd nanoflowers supported amino-functionalized fullerene(C60-NH2/Pd NFs)is evidenced by UV-vis and powder X-ray diffraction(XRD).The morphology of Pd NFs over the C60-NH2 surface has been investigated by high-resolution transmission electron microscopy(TEM)and Fourier-transform infrared(FT-IR)techniques.The supported Pd nanoflowers(Pd NFs/C60-NH2)exhibit remarkably superior catalytic activity toward the reduction of 4-nitrophenol(4-NP).It exhibits remarkable UV-vis spectra response from 4-nitrophenol to 4-aminophenol(4-AP)(99%in 2.0 min)with a turnover frequency of 12.35 min^-1.Its excellent catalytic stability and durability offer the promising application in catalysis.展开更多
Considering the high filling ratios,high densities,and narrow absorbing bandwidths of the current electromagnetic wave(EMW) absorbers,in this work,we successfully synthesized a 3 D hierarchical NiCo_(2) O_(4) nanoflow...Considering the high filling ratios,high densities,and narrow absorbing bandwidths of the current electromagnetic wave(EMW) absorbers,in this work,we successfully synthesized a 3 D hierarchical NiCo_(2) O_(4) nanoflowers/reduced graphene oxide(NiCo_(2) O_(4)/RGO) composite foam by a simple method under gentle condition.The NiCo_(2) O_(4) nanoflowers and unique 3 D foam structure are beneficial to the refraction and scattering of EMW,which endows the prepared 3 D foam with highly efficient EMW absorption performance.When the ratio between NiCo_(2) O_(4) and RGO in the foam is 1:1,5% mass fraction of NiCo_(2) O_(4/)RGO foam in paraffin wax can reach a minimum reflection loss(RL_(min)) value of-52.2 dB with a thin thickness merely 2.6 mm.Simultaneously,the effective absorption bandwidth(EAB,RL exceeding-10 dB) is7.04 GHz that covers the whole Ku band(10.96-18 GHz).Moreover,the effects of the thickness of the absorber and the loading ratios of the foam in paraffin wax matrix on the EMW absorption properties are also carefully investigated.The results indicate that the optimum EMW absorption performance of NiCo_(2) O_(4/)RGO can be tuned in different bands.The EMW absorption mechanism is ascribed to the proper impedance matching and larger dielectric and magnetic loss produced by the synergy of NiCo_(2) O_(4) and RGO.Therefore,the NiCo_(2) O_(4/)RGO hybrid foam is ideal candidate to be used as high-efficient EMW absorbers with low filling ratio,light weight,and broad frequency bandwidths.展开更多
Flower like rutile TiO_2 films were decorated with green-photoluminescent graphene quantum dots（GQDs） and photovoltaic properties were investigated for water splitting application. Rutile TiO_2 nanoflowers（NFs） an...Flower like rutile TiO_2 films were decorated with green-photoluminescent graphene quantum dots（GQDs） and photovoltaic properties were investigated for water splitting application. Rutile TiO_2 nanoflowers（NFs） and GQDs（average width of^12 nm） synthesized separately using a hydrothermal method and TiO_2 NFs were decorated with various amounts of GQDs solution（x = 5, 10, 15 and 20 μL） by spin coating. Optical characterization reveals that GQDs are highly luminescent and absorb UV and visible light photons with wavelengths up to 700 nm. GQDs-x/TiO_2 electrode shows a photocurrent enhancement of ~95% compared to pristine TiO_2 NFs for the optimum sample（x = 15 μL） at an applied potential of P = 0 V using 1 M Na_2SO_4 solution as electrolyte.展开更多
In this paper,we reported that chiral gold nanoflowers with the concentration of 0.08 mM can enhance the specificity of polymerase chain reaction(PCR)and eliminate unspecific products,and the efficiency of PCR decline...In this paper,we reported that chiral gold nanoflowers with the concentration of 0.08 mM can enhance the specificity of polymerase chain reaction(PCR)and eliminate unspecific products,and the efficiency of PCR declines in some extent and the melt temperature of PCR products also raises slightly,which may be associated with the enhancement of the combining power of primers and ssDNA templates and the inner stability of dsDNA by chiral gold nanoflowers.The phenomena have great potential in applications such as ultrasensitive specific detection of DNA and SNPs.展开更多
The conversion of traditional polymolybdate-based metal-organic frameworks(POMOFs) crystals to wellaligned nanoarrays are highly attractive for electrocatalytic hydrogen evolution but remains significant challenge. He...The conversion of traditional polymolybdate-based metal-organic frameworks(POMOFs) crystals to wellaligned nanoarrays are highly attractive for electrocatalytic hydrogen evolution but remains significant challenge. Herein, we demonstrated that the POMOFs nanoarrays as self-supported electrode toward hydrogen evolution with high catalytic activity and stability. Single-crystal X-ray analysis reveal the {ε-PMoV8MoⅥ4O_(3)7Zn4}(Zn-ε-Keggin) serve as secondary building blocks and directly connected to BPB organic ligands(BPB = 1,4-bis(pyrid-4-yl)benzene) to obtain novel [ε-PMoV8MoⅥ4O_(3)7(OH)3Zn4][BPB]3(named as Zn Mo-POMOF). Particularly, Zn Mo-POMOF nanoflower arrays grown in-situ on a Ni foam substrate exhibiting excellent electrocatalytic hydrogen evolution performance of 180 m V at a current density of 10 m A/cm^(2)with the Tafel slope of 66 m V/dec, thus among one of the best POMOF-based electrocatalysts reported so far. DFT calculations reveal that the bridging oxygen active sites(Oa) significantly optimizes Gibbs free energy of H*adsorption for Zn-ε-Keggin polymolybdate units(-0.07 e V), thereby increasing the intrinsic activity of the Zn Mo-POMOF.展开更多
A highly selective and sensitive electrochemical method was developed for the detection of serotonin (5-hydroxytryptamine, 5-HT) at gold nanoflowers (Au NFs) and overoxidized polypyrrole (OPPy) modified carbon fiber m...A highly selective and sensitive electrochemical method was developed for the detection of serotonin (5-hydroxytryptamine, 5-HT) at gold nanoflowers (Au NFs) and overoxidized polypyrrole (OPPy) modified carbon fiber microelectrode (CFME). Carbon fiber was firstly modified with gold nanoflowers using electroless deposition method, and then modified with overoxidized polypyrrole using electrochemical polymerization and overoxidization to obtain OPPy/Au NFs/CFME. The obtained OPPy/Au NFs/CFME was characterized by field emission scanning electron microscopy and electrochemical techniques. It was found that the OPPy/Au NFs/CFME showed good sensitivity for the detection of 5-HT in the range of 10 nmol/L-7.0μmol/L with detection limit of 2.3 nmol/L, and negligible interferences from ascorbic acid, 5-hydroxyindole acetic acid and uric acid. The OPPy/Au NFs/CFME was successfully applied to the detection of 5-HT in human serum samples with good recovery. The work demonstrates that the electrochemical method, incorporating signal amplification of Au NFs with higher cation selection of OPPy, provides a promising tool for the detection of 5-HT in biological systems.展开更多
Two-dimensional(2D)MoS_(2) nanomaterials have been extensively studied due to their special structure and high theoretical capacity,but it is still a huge challenge to improve its cycle stability and achieve superior ...Two-dimensional(2D)MoS_(2) nanomaterials have been extensively studied due to their special structure and high theoretical capacity,but it is still a huge challenge to improve its cycle stability and achieve superior fast charge and discharge performance.Herein,a facile one-step hydrothermal method is proposed to synthetize an ordered and self-assembled MoS_(2) nanoflower(MoS_(2)/C NF)with expanded interlayer spacing via embedding a carbon layer into the interlayer.The carbon layer in the MoS_(2) interlayer can speed the transfer of electrons,while the nanoflower structure promotes the ions transport and improves the structural stability during the charging/discharging process.Therefore,MoS_(2)/C NF electrode exhibits exceptional rate performance(318.2 and 302.3 mA·h·g^(-1) at 5.0 and 10.0 A·g^(-1),respectively)and extraordinary cycle durability(98.8%retention after 300 cycles at a current density of 1.0 A·g^(-1)).This work provides a simple and feasible method for constructing high-performance anode composites for sodium ion batteries with excellent cycle durability and fast charge/discharge ability.展开更多
Two-dimensional(2D)semiconducting materials and transition-metal oxides are promising materials for nonvolatile memory and brain-inspired neuromorphic computing applications.However,it remains chal-lenging to obtain h...Two-dimensional(2D)semiconducting materials and transition-metal oxides are promising materials for nonvolatile memory and brain-inspired neuromorphic computing applications.However,it remains chal-lenging to obtain high-quality stacked 2D films with low energy consumptions(or drive currents)be-cause of their high interfacial resistance.In this study,we synthesized 2D Ti_(3)C_(2)T_(x)MXene-derived three-dimensional(3D)TiO_(2)nanoflowers(NFs)as a feasible resistive switching(RS)material with outstanding electronic properties and synaptic learning capabilities.The electrical and optical characteristics of the synthesized material were determined through density functional theory calculations.Electrical measure-ments of the Al/Ti_(3)C_(2)T_(x)-TiO_(2)NF/Pt memory device indicated the occurrence of forming-free switching phenomena with extremely low switching voltages(0.68-0.53 V),stable ON/OFF ratio(2.3×103),and retention greater than 105 s.The Holt-Winters exponential smoothing technique was used for mod-eling and predicting the switching voltages of the RS device.The mechanism underlying the reliable RS was confirmed by observing the dense conductive filaments through conductive atomic force mi-croscopy.Interestingly,the 2D Ti_(3)C_(2)T_(x)MXene-derived 3D TiO_(2)NF-based RS device mimicked the po-tentiation/depression and spike-time-dependent plasticity of a biological synapse.Finally,a convolutional neural network was implemented based on the observed synaptic weights of Al/Ti_(3)C_(2)T_(x)-TiO_(2)NF/Pt for image-edge detection.展开更多
基金National Natural Science Foundation of China(52171101)Fundamental Research Funds for the Central Universities(2024IAIS-QN009)National Key R&D Program of China(2021YFB3701100)。
文摘CuS-C50,the cathode materials for magnesium ion batteries,was synthesized by adding the surfactant cetyltrimethyl ammonium bromide(CTAB)and adjusting the percentage of ethylene glycol to 50vol%in hydrothermal synthesis process.Results show that CuS-C50 has the complete nanoflower structure.In aluminum chloride-pentamethylcydopentodiene/tetrahydrofuran(APC/THF)electrolyte,the CuS-C50 exhibits a high specific capacity of 331.19 mAh/g when the current density is 50 mA/g and still keeps a specific capacity of 136.92 mAh/g over 50 cycles when the current density is 200 mA/g.Results of morphology characterizations indicate that the complete nanoflower structure can provide more active sites and reduce the barriers for Mg^(2+)movement,eventually improving the charge and discharge performance of the CuS cathode materials for magnesium ion batteries.
基金supported by the National Key R&D Program of China(2021YFC2400500)Shanghai Committee of Science and Technology,China(20S31901200)+2 种基金the Fundamental Research Funds for the Central Universities(2022ZYGXZR042)Postdoctoral Science Foundation of China(2022M723288)GDPH Supporting Fund for Talent Program(KY0120220137).
文摘The rapid corrosion rate and limited biological functionality still pose challenges for magnesium(Mg)-based implants in the treatment of complicated bone-related diseases in clinic.Herein,a multifunctional biodegradable curcumin(herbal medicine)-ferrum(Cur-Fe)nanoflower was self-assembled on plasma electrolytic oxidation(PEO)-treated Mg alloy via a facile immersion process to realize differential biological function for anti-bacteria/tumor and bone regeneration.The results indicated that Cur-Fe nanoflower coating can promote protein adsorption,cell adhesion and proliferation,exhibiting excellent biocompatibility.The Cur-Fe nanoflower coating exhibits unique degradation characteristics,as curcumin gradually decomposes into ferulic acid,aromatic aldehyde and other antibacterial substances,and the coating spontaneously converts into FeOOH nanosheets,ensuring the corrosion resistance of Mg-based implants.Moreover,Cur-Fe coating exhibits remarkable narrow gap semiconductor characteristics,which can generate reactive oxygen species(ROS)and demonstrated excellent antibacterial effect under simulated sunlight(SSL)irradiation.Meanwhile,under NIR irradiation,Cur-Fe coating showed excellent chemotherapy/photodynamic/photothermal synergetic antitumor properties in vitro and in vivo due to the introduction of curcumin,and photocatalysis and photothermal conversion properties of coating.Furthermore,Cur-Fe nanoflower coating demonstrated great osteogenesis activity in vitro and in vivo due to unique micro/nano structure,surface chemical bond,and the release of Mg and Fe ions.
基金supported by Jiangsu Province Science and Technology Plan Special Fund(BZ2022053)National Natural Science Foundation of China(42476239)+1 种基金Natural Science Research Projects of Universities in Jiangsu Province(24KJD530004)the Dean/Opening Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2021K008)。
文摘The catalytic direct synthesis of dimethyl carbonate(DMC)from CO_(2)and methanol is a crucial approach to utilizing CO_(2)and producing high-value chemicals.However,the high stability of the CO_(2)molecule imposes thermodynamic limitations on this reaction pathway,along with challenges related to insufficient catalyst activity and stability.Currently,solutions primarily focus on developing efficient catalyst.Herein,La-doped CeO_(2)nanoflower catalysts(La_(x)CeO_(2))were synthesized via hydrothermal method.Characterization reveals that La doping optimizes the pore structure and enriched oxygen vacancies,thereby enhancing catalytic performance.Notably,La_(0.1)CeO_(2)exhibits the largest pore size and highest oxygen vacancy content,achieving a remarkable DMC productivity of 9.42 mmol/g under 140℃,4 MPa of CO_(2),and 3 h of reactio n,surpassing pure CeO_(2)nano flowers.Based on experimental findings and in-situ diffuse infrared Fourier transform analysis,a plausible reaction pathway was proposed.This work underscores the potential of La_(x)CeO_(2)nano flowers as efficient catalysts for sustainable CO_(2)conversion to DMC.
基金support provided by the Ministry of Higher Education Malaysia under the Fundamental Research Grant Scheme(FRGS)(No.FRGS/1/2024/TK08/XMU/02/1)supported by the PETRONAS-Academia Collaboration Dialogue(PACD 2023)grant,provided by PETRONAS Research Sdn.Bhd.(PRSB)+6 种基金the Ministry of Science,Technology and Innovation(MOSTI)Malaysia under the Strategic Research Fund(SRF)(S.22015)supported by the National Natural Science Foundation of China(No.22202168)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515111019)support from the State Key Laboratory of Physical Chemistry of Solid Surfaces,Xiamen University(No.2023X11)supported by the Embassy of the People's Republic of China in Malaysia(EENG/0045)funded by Xiamen University Malaysia Investigatorship Grant(No.IENG/0038)Xiamen University Malaysia Research Fund(ICOE/0001,XMUMRF/2021-C8/IENG/0041 and XMUMRF/2025-C15/IENG/0080).
文摘Despite advances in photocatalytic half-reduction reactions,challenges remain in effectively utilizing electron-hole pairs in concurrent redox processes.The present study involved the construction of a p-n junction Co_(3)O_(4)/Zn_(3)In_(2)S_(6)(CoZ)hybrid with a complementary band edge potential.The photocatalyst formed by the 2D assembled-nanostructure portrayed an optimal yield of 13.8(H_(2))and 13.1(benzaldehyde)mmol g^(-1)h^(-1)when exposed to light(λ>420 nm),surpassing 1%Pt-added ZIS(12.4(H_(2))and 10.71(benzaldehyde)mmol g^(-1)h^(-1)).Around 95%of the electron-hole utilization rate was achieved.The solar-to-hydrogen(STH)and apparent quantum yield(AQY)values of 0.466%and 4.96%(420nm)achieved by this system in the absence of sacrificial agents exceeded those of previous works.The exceptional performance was mostly ascribed to the synergistic development of adjoining p-n heterojunctions and the built-in electric field for effective charge separation.Moreover,scavenger studies elucidated the intricate mechanistic enigma of the dual-redox process,in which benzaldehyde was produced via O-H activation and subsequent C-H cleavage of benzyl alcohol over CoZ hybrids.Furthermore,the widespread use of the optimal 1-CoZ composites was confirmed in multiple photoredox systems.This work presents an innovative perspective on the construction of dual-functioning p-n heterojunctions for practical photoredox applications.
基金supported by Zhejiang Provincial Natural Science Foundation of China(No.LTGS23B030002)the National Natural Science Foundation of China(Nos.21978111 and 22278175)。
文摘Traditional photo-electcatalyst structures of small noble metal nanoparticles assembling into large-scale photoactive semiconductors still suffer from agglomeration of noble metal nanoparticles,insufficient charge transfer,undesirable photoresponse ability that restricted the photo-electrocatalytic performance.To this end,a novel design strategy is proposed in this work,namely integrating small-scale photoactive materials(doped graphene quantum dots,S,N-GQDs)with large-sized noble metal(Pd P)nanoflowers to form novel photo-electrocatalysts for high-efficient alcohol oxidation reaction.As expected,superior electrocatalytic performance of Pd P/S,N-GQDs for ethylene glycol oxidation is acquired,thanks to the nanoflower structure with larger specific surface area and abundant active sites.Furthermore,nonmetal P are demonstrated,especially optimizing the adsorption strength,enhancing the interfacial contact,reducing metal agglomeration,ensuring uniform and efficient doping of S,N-GQDs,and ultimately significantly boost the catalytic activity of photo-electrocatalysts.
基金supported by the National Natural Science Foundation of China(Nos.22278169 and 51973078)the Excellent Scientific Research and Innovation team of the Education Department of Anhui Province(No.2022AH010028)+2 种基金the Major projects of the Education Department of Anhui Province(No.2022AH040068)the Key Foundation of Educational Commission of Anhui Province(Nos.2022AH050396 and 2022AH050376)Anhui Provincial Quality Engineering Project(No.2022sx134).
文摘This study ingeniously synthesized a novel CdS/NiS hollow nanoflower sphere(HNS)using a one-step method to enhance photocatalytic hydrogen production activity.Compared to conventional preparation methods,this approach features seamlessly interfaced contact that facilitates efficient electron transfer across the interface.The internal hollow structure allows for multiple light reflections,maximizing light absorption,while the exterior shell and inner surfaces simultaneously offer active sites for reactions.The modification with non-noble metal NiS enables the extraction of electrons from CdS to the NiS surface,achieving rapid charge separation.Furthermore,adsorption-free energy calculations reveal that the NiS surface is more conducive to photocatalytic hydrogen generation,providing additional reaction active sites.The results demonstrate a hydrogen production rate of 2.18 mmol g^(-1)h^(-1)for CdS/NiS HNS,which is 9.48 times greater than that of pristine CdS.This work presents a novel approach for synthesizing seamlessly interfaced contacts between photocatalysts and cocatalysts,offering new insight into efficient one-step synthesis for enhanced photocatalytic performance.
基金Research Supporting Project(RefRSP-2021/160)King Saud University。
文摘In this work Gd/La@ZnO nanoflower photocatalyst was successfully synthesized by a co-precipitation method and applied for rhodamine B(Rh B)and tetracycline(TCN)degradation under direct sunlight irradiation.The doping of rare earth elements extends the optical absorption wavelength of ZnO from UV region(390 nm)to visible-light region(401 nm).In addition,the co-doped ZnO nanoflower exhibits a lower charge recombination efficiency which was confirmed by photoluminescence emission analysis.Moreover,the co-doped ZnO nanoflower exhibits the maximum degradation efficiency of 91%for Rh B and 74%for TCN under sunlight irradiation.The calculated synergistic index of co-doped ZnO is higher than that of the pure ZnO.Reactive radicals’production was confirmed by terephthalic acid(TA)and nitro-blue tetrazolium(NBT)tests.The holes and hydroxyl(·OH)radicals play the major role in degradation reaction and it was confirmed by scavenger’s test.Moreover,the recycling test confirms the stability of the photocatalyst.
基金The financial support of the Natural Science Foundation of Changsha,China(No.kq2202094)National Key R&D Program of China(No.2021YFB3701400)。
文摘Vertical MoS2nanosheets were controllably patterned onto graphene as nanoflowers through a two-step hydrothermal method. The interconnected network and intimate contact between MoS2nanosheets and graphene by vertical channels enabled a high mechanical integrity of electrode and cycling stability. In particular, MoS2/graphene nanoflowers anode delivered an ultrahigh specific capacity of 901.8 mA·h/g after 700 stable cycles at 1000 mA/g and a corresponding capacity retention as 98.9% from the second cycle onwards.
文摘A new amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase at the glassy carbon electrode modified with zinc oxide nanoflowers produced by electrodeposition onto multi-walled carbon nanotubes （MWNTs） film. The morphology of the MWNTs/nano-ZnO electrode has been investigated by scanning electron microscopy （SEM）, and the electrochemical performance of the electrode has also been studied by amperometric method. The resulting electrode offered an excellent detection for hydrogen peroxide at -0.11 V with a linear response range of 9.9×10^-7 to 2.9×10^-3 mol/L with a correlation coefficient of 0.991, and response time 〈5 s. The biosensor displays rapid response and expanded linear response range, and excellent stability.
基金supported by the National Natural Science Foundation of China(No.20977086,21076196,21177115)the Science and Technology Project of Zhejiang Province,China(No.2012C23026,2011C31041)
文摘A series of TiO2 with different crystal phases and morphologies was synthesized via a facile hydrothermal process using titanium nbutoxide and concentrated hydrochloric acid as raw materials. The photocatalytic activity of the samples was evaluated by degradation of Methyl Orange in aqueous solution under UV-Visible light irradiation. On the basis of detailed analysis of the characterizing results of high-resolution transmission electron microscopy, X-ray powder diffraction measurements, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller measurement, it was concluded that the photo-activity of the catalyst is related directly to the 3D morphology and the crystal phase composition. An excellent catalyst should have both a futile 3D flower-like structure and anatase granulous particles. The 3D flower-like structure could enhance light harvesting, as well as the transfer of reactant molecules from bulk solution to the reactive sites on TiO2. In addition, the optimum anatase/rutile phase ratio was found to be 80：20, which is beneficial to the effective separation of the photogenerated electron-hole pairs.
基金supported by the National Key R&D Program of China(No.2016YFA0203102)the National Natural Science Foundation of China(Nos.21620102008 and 21827815)。
文摘Alloy and small size nanostructure s are favorable to catalytical performance,but not to surface-enhanced Raman spectroscopy(SERS) applications.Integrating SERS and catalytic activity into the nanocrystals with both alloy and small size structures is of great interest in fabrication of SERS platform to in situ monitor catalytical reaction.Herein,we report a facile method to synthesize Au@AgPd trimetallic nanoflowers(Au@AgPd NFs) with both SERS and catalytic activities,through simultaneous selective growth of Ag and Pd on Au core to form highly-branched alloy shell.These nanocrystals have the properties of small sizes,defects abundance,and highly-dispersed alloy shell which offer superior catalytic activity,while the merits of monodisperse,excellent stability,and highly-branched shell and core/alloy-shell structure promise the enhanced SERS activity.We further studied their growth mechanisms,and found that the ratio of Ag to Pd,sizes of Au core,and surfactant cetyltrimethylammonium bromide together determine this special structure.Using this as-synthesized nanocrystals,a monolayer bifunctional platform with both SERS and catalytical activity was fabricated through selfassembly at air/water interface,and applied to in situ SERS monitoring the reaction process of Pdcatalyzed hydrogenation of 4-nitrothiophenol to 4-aminothio p henol.
基金supported by the National Natural Science Foundation of China (21972124, 22272148)the Priority Academic Program Development of Jiangsu Higher Education Institution。
文摘Bi-functional electrocatalysts for acid overall water splitting reactions are crucial but still challenging to the development of proton exchange membrane water electrolysis.Herein,an efficient bi-functional catalyst of Ir/MoS_(2) nanoflowers(Ir/MoS_(2) NFs) catalyst was reported for acidic water electrolysis which can be constructed by coupling three-dimensionally interconnected MoS_(2) NFs with ultrafine Ir nanoparticles.A more suitable adsorption ability for the H* and *OOH intermediates was revealed,where the Ir sites were proposed as the main active center and MoS_(2) promoted the charge relocation to electronically modify the interfacial structure.The significant interfacial charge redistribution between the MoS_(2) NFs and the Ir active sites synergistically induced excellent catalytic activity and stability for the water electrolysis reaction.Specifically,the catalyst required overpotentials of 270 and 35 mV to reach a kinetic current density of 10 mA cm^(-2)for OER and HER,respectively,loading on the glass carbon electrode,with high catalytic kinetics,stability,and catalytic efficiency.A two-electrode system constructed by Ir/MoS_(2) NFs drove 10 mA cm^(-2)at a cell voltage of 1.55 V,about 70 mV lower than that of the commercial Pt/C||IrO_(2) system.In addition,partial surface oxidation of Ir nanoparticles to generate high-valent Ir species was also found significant to accelerate OER.The enhanced catalytic performance was attributed to the strong metal-support interaction in the Ir/MoS_(2) NFs catalyst system that changed the electronic structure of Ir metal and promoted the synergistic catalytic effect between Ir and MoS_(2) NFs.The work presented a novel platform of Ir-catalyst for proton exchange membrane water electrolysis.
基金financially supported by the Natural Science Foundation of Shanxi Province,China(No.201801D121042)。
文摘In this study,we report the synthesis of novel palladium nanoflowers(Pd NFs)on amino-functionalized fullerene(C60-NH2)by hydrothermal self-assembly growth using ethylenediamine(EA)as a functional reagent.The successful formation of Pd nanoflowers supported amino-functionalized fullerene(C60-NH2/Pd NFs)is evidenced by UV-vis and powder X-ray diffraction(XRD).The morphology of Pd NFs over the C60-NH2 surface has been investigated by high-resolution transmission electron microscopy(TEM)and Fourier-transform infrared(FT-IR)techniques.The supported Pd nanoflowers(Pd NFs/C60-NH2)exhibit remarkably superior catalytic activity toward the reduction of 4-nitrophenol(4-NP).It exhibits remarkable UV-vis spectra response from 4-nitrophenol to 4-aminophenol(4-AP)(99%in 2.0 min)with a turnover frequency of 12.35 min^-1.Its excellent catalytic stability and durability offer the promising application in catalysis.
基金financially supported by the Fundamental Research Funds for the Central Universities (No. 202065001)the National Natural Science Foundation of China (No. 51572249)+1 种基金the National Natural Science Foundation Joint Fund (No. U1806223)the State Key Laboratory of Marine Coatings (GZ-19-0004)。
文摘Considering the high filling ratios,high densities,and narrow absorbing bandwidths of the current electromagnetic wave(EMW) absorbers,in this work,we successfully synthesized a 3 D hierarchical NiCo_(2) O_(4) nanoflowers/reduced graphene oxide(NiCo_(2) O_(4)/RGO) composite foam by a simple method under gentle condition.The NiCo_(2) O_(4) nanoflowers and unique 3 D foam structure are beneficial to the refraction and scattering of EMW,which endows the prepared 3 D foam with highly efficient EMW absorption performance.When the ratio between NiCo_(2) O_(4) and RGO in the foam is 1:1,5% mass fraction of NiCo_(2) O_(4/)RGO foam in paraffin wax can reach a minimum reflection loss(RL_(min)) value of-52.2 dB with a thin thickness merely 2.6 mm.Simultaneously,the effective absorption bandwidth(EAB,RL exceeding-10 dB) is7.04 GHz that covers the whole Ku band(10.96-18 GHz).Moreover,the effects of the thickness of the absorber and the loading ratios of the foam in paraffin wax matrix on the EMW absorption properties are also carefully investigated.The results indicate that the optimum EMW absorption performance of NiCo_(2) O_(4/)RGO can be tuned in different bands.The EMW absorption mechanism is ascribed to the proper impedance matching and larger dielectric and magnetic loss produced by the synergy of NiCo_(2) O_(4) and RGO.Therefore,the NiCo_(2) O_(4/)RGO hybrid foam is ideal candidate to be used as high-efficient EMW absorbers with low filling ratio,light weight,and broad frequency bandwidths.
基金Research Council of the Tarbiat Modares University for financial supports
文摘Flower like rutile TiO_2 films were decorated with green-photoluminescent graphene quantum dots（GQDs） and photovoltaic properties were investigated for water splitting application. Rutile TiO_2 nanoflowers（NFs） and GQDs（average width of^12 nm） synthesized separately using a hydrothermal method and TiO_2 NFs were decorated with various amounts of GQDs solution（x = 5, 10, 15 and 20 μL） by spin coating. Optical characterization reveals that GQDs are highly luminescent and absorb UV and visible light photons with wavelengths up to 700 nm. GQDs-x/TiO_2 electrode shows a photocurrent enhancement of ~95% compared to pristine TiO_2 NFs for the optimum sample（x = 15 μL） at an applied potential of P = 0 V using 1 M Na_2SO_4 solution as electrolyte.
基金supported by Chinese Key Basic Research Project(2010CB933901and 2011CB933100)863 Key Project(2007AA022004)+2 种基金New Century Excellent Talent of Ministry of Education of China(NCET-08-0350 and No.20070248050)National Major Scientific Projects for the Prevention and Control of HIV/AIDS and Viral Hepatitis of China(Nos.2009ZX10004-311)Shanghai Science and Technology Fund(10XD1406100 and 1052nm04100).
文摘In this paper,we reported that chiral gold nanoflowers with the concentration of 0.08 mM can enhance the specificity of polymerase chain reaction(PCR)and eliminate unspecific products,and the efficiency of PCR declines in some extent and the melt temperature of PCR products also raises slightly,which may be associated with the enhancement of the combining power of primers and ssDNA templates and the inner stability of dsDNA by chiral gold nanoflowers.The phenomena have great potential in applications such as ultrasensitive specific detection of DNA and SNPs.
基金supported by grants from the National Natural Science Foundation of China (Nos. 22071125 and 22071126)Natural Science Foundation of Shandong Province (No.ZR^(2)020QB140)。
文摘The conversion of traditional polymolybdate-based metal-organic frameworks(POMOFs) crystals to wellaligned nanoarrays are highly attractive for electrocatalytic hydrogen evolution but remains significant challenge. Herein, we demonstrated that the POMOFs nanoarrays as self-supported electrode toward hydrogen evolution with high catalytic activity and stability. Single-crystal X-ray analysis reveal the {ε-PMoV8MoⅥ4O_(3)7Zn4}(Zn-ε-Keggin) serve as secondary building blocks and directly connected to BPB organic ligands(BPB = 1,4-bis(pyrid-4-yl)benzene) to obtain novel [ε-PMoV8MoⅥ4O_(3)7(OH)3Zn4][BPB]3(named as Zn Mo-POMOF). Particularly, Zn Mo-POMOF nanoflower arrays grown in-situ on a Ni foam substrate exhibiting excellent electrocatalytic hydrogen evolution performance of 180 m V at a current density of 10 m A/cm^(2)with the Tafel slope of 66 m V/dec, thus among one of the best POMOF-based electrocatalysts reported so far. DFT calculations reveal that the bridging oxygen active sites(Oa) significantly optimizes Gibbs free energy of H*adsorption for Zn-ε-Keggin polymolybdate units(-0.07 e V), thereby increasing the intrinsic activity of the Zn Mo-POMOF.
基金the National Natural Science Foundation of China (Nos. 21775097 and 21804106)the China Postdoctoral Science Foundation (No. 2017M620444)the Fundamental Research Funds for the Central Universities (Nos. XJJ2018247 and GK201801006)
文摘A highly selective and sensitive electrochemical method was developed for the detection of serotonin (5-hydroxytryptamine, 5-HT) at gold nanoflowers (Au NFs) and overoxidized polypyrrole (OPPy) modified carbon fiber microelectrode (CFME). Carbon fiber was firstly modified with gold nanoflowers using electroless deposition method, and then modified with overoxidized polypyrrole using electrochemical polymerization and overoxidization to obtain OPPy/Au NFs/CFME. The obtained OPPy/Au NFs/CFME was characterized by field emission scanning electron microscopy and electrochemical techniques. It was found that the OPPy/Au NFs/CFME showed good sensitivity for the detection of 5-HT in the range of 10 nmol/L-7.0μmol/L with detection limit of 2.3 nmol/L, and negligible interferences from ascorbic acid, 5-hydroxyindole acetic acid and uric acid. The OPPy/Au NFs/CFME was successfully applied to the detection of 5-HT in human serum samples with good recovery. The work demonstrates that the electrochemical method, incorporating signal amplification of Au NFs with higher cation selection of OPPy, provides a promising tool for the detection of 5-HT in biological systems.
基金National Natural Science Foundation of China(51874142)Pearl River S&T Nova Program of Guangzhou(201806010031)+3 种基金the Fundamental Research Funds for the Central Universities(2019JQ09)Guangdong Innovative and Entrepreneurial Research Team Program(2016ZT06N569)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2019TQ05L903)Young Elite Scientists Sponsorship Program by CAST(2019QNRC001).
文摘Two-dimensional(2D)MoS_(2) nanomaterials have been extensively studied due to their special structure and high theoretical capacity,but it is still a huge challenge to improve its cycle stability and achieve superior fast charge and discharge performance.Herein,a facile one-step hydrothermal method is proposed to synthetize an ordered and self-assembled MoS_(2) nanoflower(MoS_(2)/C NF)with expanded interlayer spacing via embedding a carbon layer into the interlayer.The carbon layer in the MoS_(2) interlayer can speed the transfer of electrons,while the nanoflower structure promotes the ions transport and improves the structural stability during the charging/discharging process.Therefore,MoS_(2)/C NF electrode exhibits exceptional rate performance(318.2 and 302.3 mA·h·g^(-1) at 5.0 and 10.0 A·g^(-1),respectively)and extraordinary cycle durability(98.8%retention after 300 cycles at a current density of 1.0 A·g^(-1)).This work provides a simple and feasible method for constructing high-performance anode composites for sodium ion batteries with excellent cycle durability and fast charge/discharge ability.
基金supported by the National Research Foundation of Korea (NRF)grant funded by the Korean government (No.2016R1A3B 1908249)the Samsung Semiconductor Research Center at Korea University for their support (No.IO201211-08116-01).
文摘Two-dimensional(2D)semiconducting materials and transition-metal oxides are promising materials for nonvolatile memory and brain-inspired neuromorphic computing applications.However,it remains chal-lenging to obtain high-quality stacked 2D films with low energy consumptions(or drive currents)be-cause of their high interfacial resistance.In this study,we synthesized 2D Ti_(3)C_(2)T_(x)MXene-derived three-dimensional(3D)TiO_(2)nanoflowers(NFs)as a feasible resistive switching(RS)material with outstanding electronic properties and synaptic learning capabilities.The electrical and optical characteristics of the synthesized material were determined through density functional theory calculations.Electrical measure-ments of the Al/Ti_(3)C_(2)T_(x)-TiO_(2)NF/Pt memory device indicated the occurrence of forming-free switching phenomena with extremely low switching voltages(0.68-0.53 V),stable ON/OFF ratio(2.3×103),and retention greater than 105 s.The Holt-Winters exponential smoothing technique was used for mod-eling and predicting the switching voltages of the RS device.The mechanism underlying the reliable RS was confirmed by observing the dense conductive filaments through conductive atomic force mi-croscopy.Interestingly,the 2D Ti_(3)C_(2)T_(x)MXene-derived 3D TiO_(2)NF-based RS device mimicked the po-tentiation/depression and spike-time-dependent plasticity of a biological synapse.Finally,a convolutional neural network was implemented based on the observed synaptic weights of Al/Ti_(3)C_(2)T_(x)-TiO_(2)NF/Pt for image-edge detection.
