The hydrogen evolution reaction performance of semiconducting 2H-phase molybdenum disulfide(2H-MoS_(2))presents a significant hurdle in realizing its full potential applications.Here,we utilize theoretical calculation...The hydrogen evolution reaction performance of semiconducting 2H-phase molybdenum disulfide(2H-MoS_(2))presents a significant hurdle in realizing its full potential applications.Here,we utilize theoretical calculations to predict possible functionalized graphene quantum dots(GQDs),which can enhance HER activity of bulk MoS_(2).Subsequently,we design a functionalized GQD-induced in-situ bottom-up strategy to fabricate near atom-layer 2H-MoS_(2) nanosheets mediated with GQDs(ALQD)by modulating the concentration of electron withdrawing/donating functional groups.Experimental results reveal that the introduction of a series of functionalized GQDs during the synthesis of ALQD plays a crucial role.Notably,the higher the concentration and strength of electron-withdrawing functional groups on GQDs,the thinner and more active the resulting ALQD are.Remarkably,the synthesized near atom-layer ALQD-SO_(3)demonstrate significantly improved HER performance.Our GQD-induced strategy provides a simple and efficient approach for expanding the catalytic application of MoS_(2).Furthermore,it holds substantial potential for developing nanosheets in other transition-metal dichalcogenide materials.展开更多
MoS2/C composites are considered to have great application potential in sodium-ion batteries(SIBs).It is a challenging and meaningful subject that developing high-performance anode materials via combining MoS2 and car...MoS2/C composites are considered to have great application potential in sodium-ion batteries(SIBs).It is a challenging and meaningful subject that developing high-performance anode materials via combining MoS2 and carbon effectively to give free rein to their advantages in sodium ion storage.In this work,a novel MoS2-C material was designed by using cellulose nanocrystals(CNCs)as low-cost and green carbon source.3 D hierarchical microspheres(200-250 nm)constructed by ultrathin MoS2-C nanosheets were synthesized by synchronizing the pre-carbonization of CNCs with the formation of MoS2 in hydrothermal reaction and subsequent pyrolysis process.It is found that the ultrathin MoS2-C nanosheets were composed of CNCs-derived short-range ordered carbon and few-layered MoS2.Benefiting from the unique structure and robust combination of MoS2 and CNCs-derived carbon,the ultrathin MoS2-C nanosheets composite was proved to have excellent cycling stability and superior rate performance in sodium-ion half-cell test and have high first reversible specific capacity of 397.9 m Ah/g in full-cell test.This work provides a significant and effective pathway to prepare MoS2-C materials with excellent electrochemical performance for the application in large-scale energy storage systems.展开更多
Ultrathin small MoS2nanosheets exhibit a higher electrocatalytic activity for the hydrogen evolution reaction.However,strong interactions between MoS2layers may result in aggregation;together with the low conductivity...Ultrathin small MoS2nanosheets exhibit a higher electrocatalytic activity for the hydrogen evolution reaction.However,strong interactions between MoS2layers may result in aggregation;together with the low conductivity of MoS2,this may lower its electrocatalytic activity.In this paper we present a method that we developed to directly produce solid S,N co‐doped carbon(SNC)with a graphite structure and multiple surface groups through a hydrothermal route.When Na2MoO4was added to the reaction,polymolybdate could be anchored into the carbon materials via a chemical interaction that helps polymolybdate disperse uniformly into the SNC.After a high temperature treatment,polymolybdate transformed into MoS2at800°C for6h in a N2atmosphere at a heating rate of5°C/min,owing to S2?being released from the SNC during the treatment(denoted as MoS2/SNC‐800‐6h).The SNC effectively prevents MoS2from aggregating into large particles,and we successfully prepared highly dispersed MoS2in the SNC matrix.Electrochemical characterizations indicate that MoS2/SNC‐900‐12h exhibits a low onset potential of115mV and a low overpotential of237mV at a current density of10mA/cm2.Furthermore,MoS2/SNC‐900‐12h also had an excellent stability with only^2.6%decay at a current density of10mA/cm2after5000test cycles.展开更多
We obtain molybdenum disulfide (MoS2) nanosheets (NSs) with edge sizes of 18μm by direct sulfuration of MoO3 powder spread on the SiO2/Si substrates. However, the undesirable MoO3 nanoparticles (NPs) left on th...We obtain molybdenum disulfide (MoS2) nanosheets (NSs) with edge sizes of 18μm by direct sulfuration of MoO3 powder spread on the SiO2/Si substrates. However, the undesirable MoO3 nanoparticles (NPs) left on the surface of MoS22 NSs poison the MoO3 precursor. Introducing Te vapors to react with MoS2 to form low melting point intermediate MoSxTe2-x, the evaporations of MoO3 precursor recover and MoO3 NPs disappear. Thus Te vapor is effective to suppress poisoning of the MoO3 precursor. Selecting the appropriate amount of Te vapor, we fabricate monolayer MoS22 NSs up to 70μm in edge length. This finding can be significant to understand the role of Te in the Te-assisted chemical vapor deposition growth process of layered chalcogenide materials.展开更多
Carbon and few-layer MoS2 nanosheets co- modified TiO2 nanocomposites (defined as MoS2-C@TiO2) were prepared through a facile one-step pyrolysis reaction technique. In this unique nanostructure, the TiO2 nanosh- eet...Carbon and few-layer MoS2 nanosheets co- modified TiO2 nanocomposites (defined as MoS2-C@TiO2) were prepared through a facile one-step pyrolysis reaction technique. In this unique nanostructure, the TiO2 nanosh- eets with stable structure serve as the backbones, and carbon coating and few-layer MoS2 tightly adhere onto the surface of the TiO2. It needs to be pointed out that the carbon coating improves the overall electronic conductivity and the few-layer MoS2 facilitates the diffusion of lithium ions and offers more active sites for lithium-ion storage. As a result, when evaluated as lithium-ion battery anodes, the MoS2-C@TiO2 nanocomposites exhibit markedly enhanced lithium storage capability compared with pure TiO2. A high specific capacity of 180 mA.h.g-1 has been achieved during the preliminary cycles, and the specific capacity can maintain 160 mA.h.g-1 at a high current density of 1C (1C=167 mA.g-1) even after 300 discharge/ charge cycles, indicating the great potential of the MoS2- C@TiO2 on energy storage.展开更多
Due to its unique physical,chemical and surface electronic properties,molybdenum disulfide(MoS_(2))nanosheets open up a new avenue for nitrogen dioxide(NO2)detection at room temperature.Nevertheless,the gas sensing pr...Due to its unique physical,chemical and surface electronic properties,molybdenum disulfide(MoS_(2))nanosheets open up a new avenue for nitrogen dioxide(NO2)detection at room temperature.Nevertheless,the gas sensing properties of pure MoS_(2) nanosheets are inevitably degenerated by the adsorption of atmospheric oxygen,which results in weak stability for MoS_(2)-based gas sensors.Reducing surface defects and constructing heterojunctions may be effective strategies to improve the gas sensing properties of MoS_(2) nanosheets.In this work,we design a novel nanocomposite based on MoS_(2) nanosheets decorated with tin disulfide(SnS_(2))nanoparticles(MoS_(2)/SnS_(2))via combining the mechanical exfoliation method with the facile hydrothermal method.The experimental results indicate that,after surfaces decoration with SnS_(2) nanoparticles,the as-prepared gas sensor based on MoS_(2)/SnS_(2) nanocomposites exhibits reliable long-term stability with the maximum response value drift of less than 3%at room temperature.Moreover,the MoS_(2)/SnS_(2) sensor also possesses desirable gas sensing properties upon NO_(2) at room temperature,such as high sensitivity,rapid response/recovery speed(28 s/3 s,5×10^(-6) NO_(2)),satisfactory selectivity,favorable repeatability and reversibility.The improved gas sensing properties of MoS_(2)/SnS_(2) nanocomposites can be attributed to the unique electronic properties of MoS 2 nanosheets with the fewer layers structure and the competitive adsorption effect of SnS_(2) nanoparticles.This work elucidates that SnS_(2) nanoparticles serving as an effective antioxidative decoration can promote the stability of MoS_(2) nanosheets,providing a promising approach to achieve high-stability NO2 gas sensors at room temperature.展开更多
Developing low-cost and high-efficiency photocatalysts for hydrogen production from solar water splitting is intriguing but challenging. In this study, unique one-dimensional (1D) multi-node MoS2/CdS hetero-nanowir...Developing low-cost and high-efficiency photocatalysts for hydrogen production from solar water splitting is intriguing but challenging. In this study, unique one-dimensional (1D) multi-node MoS2/CdS hetero-nanowires (NWs) for efficient visible-light photocatalytic H2 evolution are synthesized via a facile hydrothermal method. Flower-like sheaths are assembled from numerous_ defect-rich O-incorporated {0001} MoS2 facet surrounded CdS NW stems are ultrathin nanosheets (NSs), and {1120}- grown preferentially along the c-axis. Interestingly, the defects in the MoS2 NSs provide additional active S atoms on the exposed edge sites, and the incorporation of O reduces the energy barrier for H2 evolution and increases the electric conductivity of the MoS2 NSs. Moreover, the recombination of photoinduced charge carriers is significantly inhibited by the heterojunction formed between the MoS2 NSs and CdS NWs. Therefore, in the absence of noble metals as co-catalysts, the 1D MoS2 NS/CdS NW hybrids exhibit an excellent H2-generation rate of 10.85 mmol·g^-1·h^-1 and a quantum yield of 22.0% at ,λ = 475 nm, which is far better than those of Pt/CdS NWs, pure MoS2 NSs, and CdS NWs as well as their physical mixtures. Our results contribute to the rational construction of highly reactive nanostructures for various catalytic applications.展开更多
Layered molybdenum disulfide (MoS2) has received much attention as one of the most promising energy-storage and conversion materials for Li/Na ion batteries. Here, a simple and effective approach is proposed for the...Layered molybdenum disulfide (MoS2) has received much attention as one of the most promising energy-storage and conversion materials for Li/Na ion batteries. Here, a simple and effective approach is proposed for the rational design and preparation of hierarchical three-d imensional (3D) amorphous N-doped carbon nanotube@MoS2 nanosheets (3D-ANCNT@MoS2) via a simple hydrothermal method, followed by an annealing process. With such a unique nanoarchitecture, ultrathin MoS2 nanosheets grown on the external surfaces of polypyrrole-derived ANCNTs are assembled to form a hierarchical 3D nanoarchitecture, where the adopted ANCNTs serve not only as the template and continuous conductive matrix, but can also prevent MoS2 from aggregating and restacking, and help to buffer the volumetric expansion of MoS2 during cycling. More importantly, when evaluated as an anode material for lithium-ion batteries, the 3D-ANCNT@MoS2 composite exhibits excellent cycling stability, superior rate performance, and reversible specific capacity as high as 893.4 mAh·g^-1 at 0.2 A·g^-1 after 200 cycles in a half battery, and 669.4 mAh·g^-1 at 0.2 A·g^-1 after 100 cycles in the 3D-ANCNT@Mo2//LiCoO2 full battery. With respect to sodium-ion batteries, the outstanding reversible capacity, excellent rate behavior, and good cycling performance of 3D-ANCNT@MoS2 composites are also achieved.展开更多
MoS2,acting as a promising gas sensing material,has shown huge potential in monitoring of toxic and harmful gases at room temperature.However,MoS2-based gas sensors still suffer from poor gas sensing performance such ...MoS2,acting as a promising gas sensing material,has shown huge potential in monitoring of toxic and harmful gases at room temperature.However,MoS2-based gas sensors still suffer from poor gas sensing performance such as poor sensitivity,long response time.Constructing the hete ro structure is an effective approach to improve gas-sensing performance of MoS2.Herein,PbS@MoS2 composites synthesized by mechanical exfoliation combining with wet-chemical precipitation are used to investigate its performance in detecting NO2 at room temperature.The response value of PbS@MoS2 gas sensor against NO2 is significantly improved compared with the pure MoS2 gas sensor.At the same time,the modification with PbS also accelerates the response speed of MoS2,and the response time is almost reduced by two orders of magnitude,from hundreds of seconds to less than ten seconds.The enhanced response value and fast response time are mainly benefited from the modulation effect of NO2 to PbS@MoS2 heterostructure and the mechanically exfoliated MoS2 surface with few defects.This work can be expected to provide useful guidance for designing composite materials with excellent gas sensing properties.展开更多
To better understand the mechanisms of hydrogen peroxide(H_(2)O_(2))’s decomposition and reactive oxygen species(ROS)’s formation on the catalyst’s surface is always a critical issue for the environmental applicati...To better understand the mechanisms of hydrogen peroxide(H_(2)O_(2))’s decomposition and reactive oxygen species(ROS)’s formation on the catalyst’s surface is always a critical issue for the environmental application of Fenton/Fenton-like reaction.We here report a new approach to activate H_(2)O_(2) in a co-catalytic Fenton system with oxygen incorporated MoS2,namely MoS_(2−x) O_(x) nanosheets.The MoS_(2−x) O_(x) nanosheets assisted co-catalytic Fenton system exhibited superior degradation activity of emerging antibiotic contaminants(e.g.,sulfamethoxazole).Combining density functional theory(DFT)calculation and experimental investigation,we demonstrated that oxygen incorporation could improve the intrinsic conductivity of MoS_(2−x) O_(x) nanosheets and accelerate surface/interfacial charge transfer,which further leads to the efficacious activation of H_(2)O_(2).Moreover,by tuning the oxygen proportion in MoS_(2−x) O_(x) nanosheets,we are able to modulate the generation of ROS and further direct the oriented-conversion of H_(2)O_(2) to surface-bounded superoxide radical(·O_(2−surface)).It sheds light on the generation and transformation of ROS in the engineered system(e.g.,Fenton,Fenton-like reaction)for efficient degradation of persistent pollutants.展开更多
MoS2-based nanocomposites are emerging as novel versatile materials.Here,uniform Pt3Au1 nanoparticles (NPs) decorated few-layer MoS2 nanosheets were fabricated as novel enzyme mimics.Compared to pure MoS2 nanosheets...MoS2-based nanocomposites are emerging as novel versatile materials.Here,uniform Pt3Au1 nanoparticles (NPs) decorated few-layer MoS2 nanosheets were fabricated as novel enzyme mimics.Compared to pure MoS2 nanosheets,the as-prepared MoS2-Pt3Au1 nanocomposites displayed enhanced peroxidase-like activity.The nanocomposites also possessed well dispersibility and high stability in water.With these findings,a simple,fast and low-cost colorimetric detection of phenol with high sensitivity and selectivity is developed,which is based on oxidative coupling reaction of phenol and 4-aminoantipyine in the presence of H2O2 as an oxidant to form pink color products.This work provides a type of MoS2-NP composites as enzyme mimics for many potential applications in catalysis.展开更多
Liquid-phase exfoliation (LPE) is an attractive method for the scaling-up of exfoliated MoS2 sheets compared to chemical vapor deposition and mechanical cleavage. However, the MoS2 nanosheet yield from LPE is too sm...Liquid-phase exfoliation (LPE) is an attractive method for the scaling-up of exfoliated MoS2 sheets compared to chemical vapor deposition and mechanical cleavage. However, the MoS2 nanosheet yield from LPE is too small for practical applications. We report a facile method for the scaling-up of exfoliated MoS2 nanosheets using freeze-dried silk fibroin powders. Compared to MoS2 dispersion in the absence of silk fibroin powder, sonicated MoS2 dispersions with silk fibroin powder (MoSJSilk dispersion) show noticeably higher exfoliated MoS2 nanosheet yields, with suspended MoS2 concentrations in MoS2/Silk dispersions sonicated for 2 and 5 h of 1.03 and 1.39 mg.mL-1, respectively. The MoS2 concentration in the MoS2/Silk dispersion after centrifugation above 10,000 rpm is more than four times that without the silk fibroin. The size of the dispersed silk fibroin is controlled by the change of centrifugation rate, showing the removal of silk fibroin above tens of micrometers in size after centrifugation at 2,000 rpm. Size-controlled silk fibroin biomolecules combined with MoS2 nanosheets are expected to increase the practical use of such materials in fields related to tissue engineering, biosensors and electrochemical electrodes. Atomic force microscopy and Raman spectroscopy provide the height of the MoS2 nanosheets spin-cast from MoS2/Silk dispersions, showing thicknesses of 3--6 nm. X-ray photoelectron spectroscopy and X-ray diffraction indicate that the outermost surface layer of the hydrophobic MoS2 crystals interact with oxygen-containing functional groups that exist in the hydrophobic part of silk fibroins. The amphiphilic properties of silk fibroin combined with the MoS2 nanosheets stabilize dispersions by enhancing solvent-material interactions. The large quantities of exfoliated MoS2 nanosheets suspended in the as-synthesized dispersions can be utilized for the fabrication of vapor and electrochemical devices requiring high MoS2 nanosheets contents.展开更多
In this work,molybdenum disulfide quantum dots(MoS2 QDs) were firstly prepared by hydrothermal method using sodium molybdate and glutathione as precursors,and applied in ascorbic acid detection.When joining MnO2 nan...In this work,molybdenum disulfide quantum dots(MoS2 QDs) were firstly prepared by hydrothermal method using sodium molybdate and glutathione as precursors,and applied in ascorbic acid detection.When joining MnO2 nanosheets into MoS2 QDs solution,they produced an obvious fluorescence quenching,which should be due to inner filter effect(IFE).Meanwhile,the fluorescent probe was formed,Interestingly,we found that this quenching phenomenon disappeared with the addition of ascorbic acid,In other words,the fluorescence gradually restored.This recovery phenomenon is mainly due to the reduction effect of ascorbic acid for MnO2 nanosheets.Under the optimum conditions,the limit of detection(LOD) of 39 nmol/L for ascorbic acid was achieved with a linear range of 0.33-5.00 μmol/L.The repeatability was better than 5.0% for ascorbic acid in both standard and fruit samples(n = 3).Moreover,the as-fabricated fluorescent sensing system was successfully employed to detect the ascorbic acid levels in hawthorn and jujube with satisfactory results.展开更多
High efficiency microwave absorption(MA)materials with tunable electromagnetic(EM)features have been highly sought.However,it is still a challenge to achieve multi-bands absorption performance by simple optimizing the...High efficiency microwave absorption(MA)materials with tunable electromagnetic(EM)features have been highly sought.However,it is still a challenge to achieve multi-bands absorption performance by simple optimizing the chemical composition of MA materials.Herein,a simple solvothermal method was used to embed magnetic Fe_(3)O_(4) nanodusters on MoS2 nanosheets,in which magnetic nanodusters weme quantitatively customized More importantly,the MA frequency and MA properties of the material are highly tailored,and multi-bands absorption is achieved.The minimum reflection loss(RL)of Fe_(3)O_(4)/MoS_(2) composite reaches-87.24 dB and is about 4 times more than pure MoS_(2) nanosheets.The effective ab-sorption bandwidth reaches 5.52 GHz(≤-10 dB).These desirable properties result from the introduction of appropriate magnetic Fe_(3)O_(4) nanoclusters,which provide optimal synegistic effect of dielectric and magnetic losses.This result provides a feasible idea for designing high efficiency MA materials with tunable EM features in the future.展开更多
基金This research was supported by Shanghai Pujiang Program(21PJD022)National Natural Science Foundation of China(21901154).
文摘The hydrogen evolution reaction performance of semiconducting 2H-phase molybdenum disulfide(2H-MoS_(2))presents a significant hurdle in realizing its full potential applications.Here,we utilize theoretical calculations to predict possible functionalized graphene quantum dots(GQDs),which can enhance HER activity of bulk MoS_(2).Subsequently,we design a functionalized GQD-induced in-situ bottom-up strategy to fabricate near atom-layer 2H-MoS_(2) nanosheets mediated with GQDs(ALQD)by modulating the concentration of electron withdrawing/donating functional groups.Experimental results reveal that the introduction of a series of functionalized GQDs during the synthesis of ALQD plays a crucial role.Notably,the higher the concentration and strength of electron-withdrawing functional groups on GQDs,the thinner and more active the resulting ALQD are.Remarkably,the synthesized near atom-layer ALQD-SO_(3)demonstrate significantly improved HER performance.Our GQD-induced strategy provides a simple and efficient approach for expanding the catalytic application of MoS_(2).Furthermore,it holds substantial potential for developing nanosheets in other transition-metal dichalcogenide materials.
基金supported by the National Natural Science Foundation of China(Grant No.51974114,51672075,and 21908049)Natural Science Foundation of Hunan Province and the Fundamental Research Funds for the Central Universities。
文摘MoS2/C composites are considered to have great application potential in sodium-ion batteries(SIBs).It is a challenging and meaningful subject that developing high-performance anode materials via combining MoS2 and carbon effectively to give free rein to their advantages in sodium ion storage.In this work,a novel MoS2-C material was designed by using cellulose nanocrystals(CNCs)as low-cost and green carbon source.3 D hierarchical microspheres(200-250 nm)constructed by ultrathin MoS2-C nanosheets were synthesized by synchronizing the pre-carbonization of CNCs with the formation of MoS2 in hydrothermal reaction and subsequent pyrolysis process.It is found that the ultrathin MoS2-C nanosheets were composed of CNCs-derived short-range ordered carbon and few-layered MoS2.Benefiting from the unique structure and robust combination of MoS2 and CNCs-derived carbon,the ultrathin MoS2-C nanosheets composite was proved to have excellent cycling stability and superior rate performance in sodium-ion half-cell test and have high first reversible specific capacity of 397.9 m Ah/g in full-cell test.This work provides a significant and effective pathway to prepare MoS2-C materials with excellent electrochemical performance for the application in large-scale energy storage systems.
基金supported by the National Natural Science Foundation of China(21671011)Beijing High-Level Talent program~~
文摘Ultrathin small MoS2nanosheets exhibit a higher electrocatalytic activity for the hydrogen evolution reaction.However,strong interactions between MoS2layers may result in aggregation;together with the low conductivity of MoS2,this may lower its electrocatalytic activity.In this paper we present a method that we developed to directly produce solid S,N co‐doped carbon(SNC)with a graphite structure and multiple surface groups through a hydrothermal route.When Na2MoO4was added to the reaction,polymolybdate could be anchored into the carbon materials via a chemical interaction that helps polymolybdate disperse uniformly into the SNC.After a high temperature treatment,polymolybdate transformed into MoS2at800°C for6h in a N2atmosphere at a heating rate of5°C/min,owing to S2?being released from the SNC during the treatment(denoted as MoS2/SNC‐800‐6h).The SNC effectively prevents MoS2from aggregating into large particles,and we successfully prepared highly dispersed MoS2in the SNC matrix.Electrochemical characterizations indicate that MoS2/SNC‐900‐12h exhibits a low onset potential of115mV and a low overpotential of237mV at a current density of10mA/cm2.Furthermore,MoS2/SNC‐900‐12h also had an excellent stability with only^2.6%decay at a current density of10mA/cm2after5000test cycles.
基金Supported by the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China under Grant No 14XNLQ07
文摘We obtain molybdenum disulfide (MoS2) nanosheets (NSs) with edge sizes of 18μm by direct sulfuration of MoO3 powder spread on the SiO2/Si substrates. However, the undesirable MoO3 nanoparticles (NPs) left on the surface of MoS22 NSs poison the MoO3 precursor. Introducing Te vapors to react with MoS2 to form low melting point intermediate MoSxTe2-x, the evaporations of MoO3 precursor recover and MoO3 NPs disappear. Thus Te vapor is effective to suppress poisoning of the MoO3 precursor. Selecting the appropriate amount of Te vapor, we fabricate monolayer MoS22 NSs up to 70μm in edge length. This finding can be significant to understand the role of Te in the Te-assisted chemical vapor deposition growth process of layered chalcogenide materials.
基金financially supported by the National Natural Science Foundation of China(No.51472177)the China-EU Science and Technology Cooperation Project(No.SQ2013ZOA100006)
文摘Carbon and few-layer MoS2 nanosheets co- modified TiO2 nanocomposites (defined as MoS2-C@TiO2) were prepared through a facile one-step pyrolysis reaction technique. In this unique nanostructure, the TiO2 nanosh- eets with stable structure serve as the backbones, and carbon coating and few-layer MoS2 tightly adhere onto the surface of the TiO2. It needs to be pointed out that the carbon coating improves the overall electronic conductivity and the few-layer MoS2 facilitates the diffusion of lithium ions and offers more active sites for lithium-ion storage. As a result, when evaluated as lithium-ion battery anodes, the MoS2-C@TiO2 nanocomposites exhibit markedly enhanced lithium storage capability compared with pure TiO2. A high specific capacity of 180 mA.h.g-1 has been achieved during the preliminary cycles, and the specific capacity can maintain 160 mA.h.g-1 at a high current density of 1C (1C=167 mA.g-1) even after 300 discharge/ charge cycles, indicating the great potential of the MoS2- C@TiO2 on energy storage.
基金financially supported by Hunan Provincial Natural Science Foundation of China(No.2018JJ2404)the Scientific Research Foundation of Hunan Provincial Education Department(Nos.19A475 and 19C1739)Hunan Science and Technology Plan Program(No.2019RS1056)。
文摘Due to its unique physical,chemical and surface electronic properties,molybdenum disulfide(MoS_(2))nanosheets open up a new avenue for nitrogen dioxide(NO2)detection at room temperature.Nevertheless,the gas sensing properties of pure MoS_(2) nanosheets are inevitably degenerated by the adsorption of atmospheric oxygen,which results in weak stability for MoS_(2)-based gas sensors.Reducing surface defects and constructing heterojunctions may be effective strategies to improve the gas sensing properties of MoS_(2) nanosheets.In this work,we design a novel nanocomposite based on MoS_(2) nanosheets decorated with tin disulfide(SnS_(2))nanoparticles(MoS_(2)/SnS_(2))via combining the mechanical exfoliation method with the facile hydrothermal method.The experimental results indicate that,after surfaces decoration with SnS_(2) nanoparticles,the as-prepared gas sensor based on MoS_(2)/SnS_(2) nanocomposites exhibits reliable long-term stability with the maximum response value drift of less than 3%at room temperature.Moreover,the MoS_(2)/SnS_(2) sensor also possesses desirable gas sensing properties upon NO_(2) at room temperature,such as high sensitivity,rapid response/recovery speed(28 s/3 s,5×10^(-6) NO_(2)),satisfactory selectivity,favorable repeatability and reversibility.The improved gas sensing properties of MoS_(2)/SnS_(2) nanocomposites can be attributed to the unique electronic properties of MoS 2 nanosheets with the fewer layers structure and the competitive adsorption effect of SnS_(2) nanoparticles.This work elucidates that SnS_(2) nanoparticles serving as an effective antioxidative decoration can promote the stability of MoS_(2) nanosheets,providing a promising approach to achieve high-stability NO2 gas sensors at room temperature.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China (Nos. 21431003 and 21521091) and China Ministry of Science and Technology (No. 2016YFA0202801). We also thank Dr. Lina Zhang and Ms. Xiaohua Gu for their kind help with the TEM measurements.
文摘Developing low-cost and high-efficiency photocatalysts for hydrogen production from solar water splitting is intriguing but challenging. In this study, unique one-dimensional (1D) multi-node MoS2/CdS hetero-nanowires (NWs) for efficient visible-light photocatalytic H2 evolution are synthesized via a facile hydrothermal method. Flower-like sheaths are assembled from numerous_ defect-rich O-incorporated {0001} MoS2 facet surrounded CdS NW stems are ultrathin nanosheets (NSs), and {1120}- grown preferentially along the c-axis. Interestingly, the defects in the MoS2 NSs provide additional active S atoms on the exposed edge sites, and the incorporation of O reduces the energy barrier for H2 evolution and increases the electric conductivity of the MoS2 NSs. Moreover, the recombination of photoinduced charge carriers is significantly inhibited by the heterojunction formed between the MoS2 NSs and CdS NWs. Therefore, in the absence of noble metals as co-catalysts, the 1D MoS2 NS/CdS NW hybrids exhibit an excellent H2-generation rate of 10.85 mmol·g^-1·h^-1 and a quantum yield of 22.0% at ,λ = 475 nm, which is far better than those of Pt/CdS NWs, pure MoS2 NSs, and CdS NWs as well as their physical mixtures. Our results contribute to the rational construction of highly reactive nanostructures for various catalytic applications.
基金This work was supported by the National Natural Science Foundation of China (No. 51672213) and the Natural Science Foundation of Shaanxi Province (Nos. 2017ZDCXL-GY-08-01 and 2017JM2025).
文摘Layered molybdenum disulfide (MoS2) has received much attention as one of the most promising energy-storage and conversion materials for Li/Na ion batteries. Here, a simple and effective approach is proposed for the rational design and preparation of hierarchical three-d imensional (3D) amorphous N-doped carbon nanotube@MoS2 nanosheets (3D-ANCNT@MoS2) via a simple hydrothermal method, followed by an annealing process. With such a unique nanoarchitecture, ultrathin MoS2 nanosheets grown on the external surfaces of polypyrrole-derived ANCNTs are assembled to form a hierarchical 3D nanoarchitecture, where the adopted ANCNTs serve not only as the template and continuous conductive matrix, but can also prevent MoS2 from aggregating and restacking, and help to buffer the volumetric expansion of MoS2 during cycling. More importantly, when evaluated as an anode material for lithium-ion batteries, the 3D-ANCNT@MoS2 composite exhibits excellent cycling stability, superior rate performance, and reversible specific capacity as high as 893.4 mAh·g^-1 at 0.2 A·g^-1 after 200 cycles in a half battery, and 669.4 mAh·g^-1 at 0.2 A·g^-1 after 100 cycles in the 3D-ANCNT@Mo2//LiCoO2 full battery. With respect to sodium-ion batteries, the outstanding reversible capacity, excellent rate behavior, and good cycling performance of 3D-ANCNT@MoS2 composites are also achieved.
基金supported by Hunan Provincial Natural Science Foundation of China(No.2018JJ2404)Scientific Research Foundation of Hunan Provincial Education Department(Nos.19A475,19C1739)Hunan Science and Technology Plan Program(No.2019RS1056)。
文摘MoS2,acting as a promising gas sensing material,has shown huge potential in monitoring of toxic and harmful gases at room temperature.However,MoS2-based gas sensors still suffer from poor gas sensing performance such as poor sensitivity,long response time.Constructing the hete ro structure is an effective approach to improve gas-sensing performance of MoS2.Herein,PbS@MoS2 composites synthesized by mechanical exfoliation combining with wet-chemical precipitation are used to investigate its performance in detecting NO2 at room temperature.The response value of PbS@MoS2 gas sensor against NO2 is significantly improved compared with the pure MoS2 gas sensor.At the same time,the modification with PbS also accelerates the response speed of MoS2,and the response time is almost reduced by two orders of magnitude,from hundreds of seconds to less than ten seconds.The enhanced response value and fast response time are mainly benefited from the modulation effect of NO2 to PbS@MoS2 heterostructure and the mechanically exfoliated MoS2 surface with few defects.This work can be expected to provide useful guidance for designing composite materials with excellent gas sensing properties.
基金the National Natural Science Foundation of China(Nos.42077293 and 22006088)Natural Science Foundation of Guangdong Province(Nos.2019A1515011692 and 2019QN01L797)+2 种基金Shenzhen Municipal Science and Technology Innovation Committee(Nos.JCYJ20190809181413713 and WDZC20200817103015002)Y.X.H.also thanks the financial support from Overseas Cooperation Research Fund of Tsinghua Shenzhen International Graduate School(Nos.HW2020002 and QD2021010N)This work was also supported by the China Postdoctoral Science Foundation(No.2019M66067).
文摘To better understand the mechanisms of hydrogen peroxide(H_(2)O_(2))’s decomposition and reactive oxygen species(ROS)’s formation on the catalyst’s surface is always a critical issue for the environmental application of Fenton/Fenton-like reaction.We here report a new approach to activate H_(2)O_(2) in a co-catalytic Fenton system with oxygen incorporated MoS2,namely MoS_(2−x) O_(x) nanosheets.The MoS_(2−x) O_(x) nanosheets assisted co-catalytic Fenton system exhibited superior degradation activity of emerging antibiotic contaminants(e.g.,sulfamethoxazole).Combining density functional theory(DFT)calculation and experimental investigation,we demonstrated that oxygen incorporation could improve the intrinsic conductivity of MoS_(2−x) O_(x) nanosheets and accelerate surface/interfacial charge transfer,which further leads to the efficacious activation of H_(2)O_(2).Moreover,by tuning the oxygen proportion in MoS_(2−x) O_(x) nanosheets,we are able to modulate the generation of ROS and further direct the oriented-conversion of H_(2)O_(2) to surface-bounded superoxide radical(·O_(2−surface)).It sheds light on the generation and transformation of ROS in the engineered system(e.g.,Fenton,Fenton-like reaction)for efficient degradation of persistent pollutants.
文摘MoS2-based nanocomposites are emerging as novel versatile materials.Here,uniform Pt3Au1 nanoparticles (NPs) decorated few-layer MoS2 nanosheets were fabricated as novel enzyme mimics.Compared to pure MoS2 nanosheets,the as-prepared MoS2-Pt3Au1 nanocomposites displayed enhanced peroxidase-like activity.The nanocomposites also possessed well dispersibility and high stability in water.With these findings,a simple,fast and low-cost colorimetric detection of phenol with high sensitivity and selectivity is developed,which is based on oxidative coupling reaction of phenol and 4-aminoantipyine in the presence of H2O2 as an oxidant to form pink color products.This work provides a type of MoS2-NP composites as enzyme mimics for many potential applications in catalysis.
文摘Liquid-phase exfoliation (LPE) is an attractive method for the scaling-up of exfoliated MoS2 sheets compared to chemical vapor deposition and mechanical cleavage. However, the MoS2 nanosheet yield from LPE is too small for practical applications. We report a facile method for the scaling-up of exfoliated MoS2 nanosheets using freeze-dried silk fibroin powders. Compared to MoS2 dispersion in the absence of silk fibroin powder, sonicated MoS2 dispersions with silk fibroin powder (MoSJSilk dispersion) show noticeably higher exfoliated MoS2 nanosheet yields, with suspended MoS2 concentrations in MoS2/Silk dispersions sonicated for 2 and 5 h of 1.03 and 1.39 mg.mL-1, respectively. The MoS2 concentration in the MoS2/Silk dispersion after centrifugation above 10,000 rpm is more than four times that without the silk fibroin. The size of the dispersed silk fibroin is controlled by the change of centrifugation rate, showing the removal of silk fibroin above tens of micrometers in size after centrifugation at 2,000 rpm. Size-controlled silk fibroin biomolecules combined with MoS2 nanosheets are expected to increase the practical use of such materials in fields related to tissue engineering, biosensors and electrochemical electrodes. Atomic force microscopy and Raman spectroscopy provide the height of the MoS2 nanosheets spin-cast from MoS2/Silk dispersions, showing thicknesses of 3--6 nm. X-ray photoelectron spectroscopy and X-ray diffraction indicate that the outermost surface layer of the hydrophobic MoS2 crystals interact with oxygen-containing functional groups that exist in the hydrophobic part of silk fibroins. The amphiphilic properties of silk fibroin combined with the MoS2 nanosheets stabilize dispersions by enhancing solvent-material interactions. The large quantities of exfoliated MoS2 nanosheets suspended in the as-synthesized dispersions can be utilized for the fabrication of vapor and electrochemical devices requiring high MoS2 nanosheets contents.
基金financially supported by National Nature Science Foundation of China (No. 21475053)
文摘In this work,molybdenum disulfide quantum dots(MoS2 QDs) were firstly prepared by hydrothermal method using sodium molybdate and glutathione as precursors,and applied in ascorbic acid detection.When joining MnO2 nanosheets into MoS2 QDs solution,they produced an obvious fluorescence quenching,which should be due to inner filter effect(IFE).Meanwhile,the fluorescent probe was formed,Interestingly,we found that this quenching phenomenon disappeared with the addition of ascorbic acid,In other words,the fluorescence gradually restored.This recovery phenomenon is mainly due to the reduction effect of ascorbic acid for MnO2 nanosheets.Under the optimum conditions,the limit of detection(LOD) of 39 nmol/L for ascorbic acid was achieved with a linear range of 0.33-5.00 μmol/L.The repeatability was better than 5.0% for ascorbic acid in both standard and fruit samples(n = 3).Moreover,the as-fabricated fluorescent sensing system was successfully employed to detect the ascorbic acid levels in hawthorn and jujube with satisfactory results.
基金The financial support comes from the National Natural Science Foundation of China(Nos.12074095,52177014,51977009,11774027)The 2020 Central Government's plan to support the Talent Training Project of the Reform and Development Fund of Local Universities(Grant No.2020YQ02).
文摘High efficiency microwave absorption(MA)materials with tunable electromagnetic(EM)features have been highly sought.However,it is still a challenge to achieve multi-bands absorption performance by simple optimizing the chemical composition of MA materials.Herein,a simple solvothermal method was used to embed magnetic Fe_(3)O_(4) nanodusters on MoS2 nanosheets,in which magnetic nanodusters weme quantitatively customized More importantly,the MA frequency and MA properties of the material are highly tailored,and multi-bands absorption is achieved.The minimum reflection loss(RL)of Fe_(3)O_(4)/MoS_(2) composite reaches-87.24 dB and is about 4 times more than pure MoS_(2) nanosheets.The effective ab-sorption bandwidth reaches 5.52 GHz(≤-10 dB).These desirable properties result from the introduction of appropriate magnetic Fe_(3)O_(4) nanoclusters,which provide optimal synegistic effect of dielectric and magnetic losses.This result provides a feasible idea for designing high efficiency MA materials with tunable EM features in the future.