g3(green gas for gird)环保气体(C_(4)F_(7)N/CO_(2)混合)作为SF_(6)最具潜力的新型环保绝缘替代气体,近几年来受到了广泛关注.通过分析g3气体绝缘组合开关设备中的分解组分来检测局部放电、过热等缺陷故障,对于电力设备运行状态的评...g3(green gas for gird)环保气体(C_(4)F_(7)N/CO_(2)混合)作为SF_(6)最具潜力的新型环保绝缘替代气体,近几年来受到了广泛关注.通过分析g3气体绝缘组合开关设备中的分解组分来检测局部放电、过热等缺陷故障,对于电力设备运行状态的评估和诊断具有重要作用.本文提出利用Si原子掺杂改性来提高MoS_(2)的气敏和吸附性能,并基于密度泛函理论(DFT)的计算方法,通过吸附能、电荷转移、态密度和局部态密度等参数指标,探究了本征MoS_(2)、Si改性MoS_(2)(Si-MoS_(2))对g3气体典型分解组分—COF_(2)、CF_(4)、CF_(3)CN的吸附气敏机理.分析表明Si原子在MoS_(2)表面具有稳定的掺杂结构,相比本征MoS_(2),Si原子改性之后的MoS_(2)的导电性得到了有效增强;Si-MoS_(2)对COF_(2)、CF_(4)气体表现出强化学吸附作用,对CF_(3)CN为弱物理吸附,吸附强度CF_(4)>COF_(2)>CF_(3)CN,且在吸附过程中Si-MoS_(2)总是作为电子供体,将电子转移到气体分子;Si改性MoS_(2)对g3气体分解组分具有选择吸附性,为检测CF_(4)、COF_(2)气体的MoS_(2)高性能气敏传感器的研制提供了理论上的基础;研究结果在减少温室气体的排放、提高GIS(Gas Insulated Switchgear)的运行稳定性等方面同样具有重要意义.展开更多
Due to the pristine interface of the 2D/3D face-tunneling heterostructure with an ultra-sharp doping profile, the 2D/3D tunneling field-effect transistor(TFET) is considered as one of the most promising low-power devi...Due to the pristine interface of the 2D/3D face-tunneling heterostructure with an ultra-sharp doping profile, the 2D/3D tunneling field-effect transistor(TFET) is considered as one of the most promising low-power devices that can simultaneously obtain low off-state current(IOFF), high on-state current(ION) and steep subthreshold swing(SS). As a key element for the 2D/3D TFET, the intensive exploration of the tunnel diode based on the 2D/3D heterostructure is in urgent need.The transfer technique composed of the exfoliation and the release process is currently the most common approach to fabricating the 2D/3D heterostructures. However, the well-established transfer technique of the 2D materials is still unavailable.Only a small part of the irregular films can usually be obtained by mechanical exfoliation, while the choice of the chemical exfoliation may lead to the contamination of the 2D material films by the ions in the chemical etchants. Moreover, the deformation of the 2D material in the transfer process due to its soft nature also leads to the nonuniformity of the transferred film,which is one of the main reasons for the presence of the wrinkles and the stacks in the transferred film. Thus, the large-scale fabrication of the high-quality 2D/3D tunnel diodes is limited. In this article, a comprehensive transfer technique that can mend up the shortages mentioned above with the aid of the water and the thermal release tape(TRT) is proposed. Based on the method we proposed, the MoS_(2)/Si tunnel diode is experimentally demonstrated and the transferred monolayer MoS_(2) film with the relatively high crystal quality is confirmed by atomic force microscopy(AFM), scanning electron microscopy(SEM), and Raman characterizations. Besides, the prominent negative differential resistance(NDR) effect is observed at room temperature, which verifies the relatively high quality of the MoS_(2)/Si heterojunction. The bilayer MoS_(2)/Si tunnel diode is also experimentally fabricated by repeating the transfer process we proposed, followed by the specific analysis of the electrical characteristics. This study shows the advantages of the transfer technique we proposed and indicates the great application foreground of the fabricated 2D/3D heterostructure for ultralow-power tunneling devices.展开更多
Phenylacetic acid(PAA)is a primary raw material for illegal Methamphetamine(MATM)synthesis under the strong precursor chemicals supervisions of safrole and isosafrole.Therefore,trace detection of PAA at ultra-low conc...Phenylacetic acid(PAA)is a primary raw material for illegal Methamphetamine(MATM)synthesis under the strong precursor chemicals supervisions of safrole and isosafrole.Therefore,trace detection of PAA at ultra-low concentration is a strategic technique and an urgent issue in the field of drug control.In this paper,trace determination of PAA at sub-nmol-L-1 concentration level is achieved by hydrogen bond adsorption and electrochemical catalysis through the prepared aminated SiO_(2)nanoparticles(SiO_(2)-NH_(2) NPs)and MoS_(2) nanosheets(NSs)modified glassy carbon electrode(GCE).The prepared MoS_(2) NS s/SiO_(2)-NH_(2) NPs modified electrode represents a detecting limit of 0.0989 nmol·L^(-1)and an obvious increasing linear range before the concentration increasement up to 60 nmol·L^(-1)in square wave voltammetry(SWV)responses of PAA.The SWV response of the modified electrode to PAA in the concentration range within 100 nmol·L^(-1)is higher than phenol,acetic acid(HOAc)and benzoic Acid(BEN).This electrochemical method for trace detection of PAA in aqueous solution with desired performance provides a feasible scheme for the detection of other drugs and aromatic precursor chemicals.展开更多
MoS_(2)is a promising electrocatalyst for hydrogen evolution reaction and a good candidate for cocatalyst to enhance the photoelectrochemical(PEC)performance of Si-based photoelectrode in aqueous electrolytes.The main...MoS_(2)is a promising electrocatalyst for hydrogen evolution reaction and a good candidate for cocatalyst to enhance the photoelectrochemical(PEC)performance of Si-based photoelectrode in aqueous electrolytes.The main challenge lies in the optimization of the microstructure of MoS_(2),to improve its catalytic activity and to construct a mechanically and chemically stable cocatalyst/Si photocathode.In this paper,a highly-ordered mesoporous MoS_(2)was synthesized and decorated onto a TiO_(2)protected p-silicon substrate.An additional TiO_(2)necking was introduced to strengthen the bonding between the MoS_(2)particles and the TiO_(2)layer.This meso-MoS_(2)/TiO_(2)/p-Si hybrid photocathode exhibited significantly enhanced PEC performance,where an onset potential of+0.06 V(versus RHE)and a current density of-1.8 mA/cm^(2)at 0 V(versus RHE)with a Faradaic efficiency close to 100%was achieved in 0.5 mol/L H_(2)SO_(4).Additionally,this meso-MoS_(2)/TiO_(2)/p-Si photocathode showed an excellent PEC ability and durability in alkaline media.This paper provides a promising strategy to enhance and protect the photocathode through high-performance surface cocatalysts.展开更多
文摘g3(green gas for gird)环保气体(C_(4)F_(7)N/CO_(2)混合)作为SF_(6)最具潜力的新型环保绝缘替代气体,近几年来受到了广泛关注.通过分析g3气体绝缘组合开关设备中的分解组分来检测局部放电、过热等缺陷故障,对于电力设备运行状态的评估和诊断具有重要作用.本文提出利用Si原子掺杂改性来提高MoS_(2)的气敏和吸附性能,并基于密度泛函理论(DFT)的计算方法,通过吸附能、电荷转移、态密度和局部态密度等参数指标,探究了本征MoS_(2)、Si改性MoS_(2)(Si-MoS_(2))对g3气体典型分解组分—COF_(2)、CF_(4)、CF_(3)CN的吸附气敏机理.分析表明Si原子在MoS_(2)表面具有稳定的掺杂结构,相比本征MoS_(2),Si原子改性之后的MoS_(2)的导电性得到了有效增强;Si-MoS_(2)对COF_(2)、CF_(4)气体表现出强化学吸附作用,对CF_(3)CN为弱物理吸附,吸附强度CF_(4)>COF_(2)>CF_(3)CN,且在吸附过程中Si-MoS_(2)总是作为电子供体,将电子转移到气体分子;Si改性MoS_(2)对g3气体分解组分具有选择吸附性,为检测CF_(4)、COF_(2)气体的MoS_(2)高性能气敏传感器的研制提供了理论上的基础;研究结果在减少温室气体的排放、提高GIS(Gas Insulated Switchgear)的运行稳定性等方面同样具有重要意义.
基金Project supported by the National Natural Science Foundation of China (Grant No.61851405)。
文摘Due to the pristine interface of the 2D/3D face-tunneling heterostructure with an ultra-sharp doping profile, the 2D/3D tunneling field-effect transistor(TFET) is considered as one of the most promising low-power devices that can simultaneously obtain low off-state current(IOFF), high on-state current(ION) and steep subthreshold swing(SS). As a key element for the 2D/3D TFET, the intensive exploration of the tunnel diode based on the 2D/3D heterostructure is in urgent need.The transfer technique composed of the exfoliation and the release process is currently the most common approach to fabricating the 2D/3D heterostructures. However, the well-established transfer technique of the 2D materials is still unavailable.Only a small part of the irregular films can usually be obtained by mechanical exfoliation, while the choice of the chemical exfoliation may lead to the contamination of the 2D material films by the ions in the chemical etchants. Moreover, the deformation of the 2D material in the transfer process due to its soft nature also leads to the nonuniformity of the transferred film,which is one of the main reasons for the presence of the wrinkles and the stacks in the transferred film. Thus, the large-scale fabrication of the high-quality 2D/3D tunnel diodes is limited. In this article, a comprehensive transfer technique that can mend up the shortages mentioned above with the aid of the water and the thermal release tape(TRT) is proposed. Based on the method we proposed, the MoS_(2)/Si tunnel diode is experimentally demonstrated and the transferred monolayer MoS_(2) film with the relatively high crystal quality is confirmed by atomic force microscopy(AFM), scanning electron microscopy(SEM), and Raman characterizations. Besides, the prominent negative differential resistance(NDR) effect is observed at room temperature, which verifies the relatively high quality of the MoS_(2)/Si heterojunction. The bilayer MoS_(2)/Si tunnel diode is also experimentally fabricated by repeating the transfer process we proposed, followed by the specific analysis of the electrical characteristics. This study shows the advantages of the transfer technique we proposed and indicates the great application foreground of the fabricated 2D/3D heterostructure for ultralow-power tunneling devices.
基金financially supported by the National Natural Science Foundation of China (Nos.62033002,62071112 and 61973058)the Program of the Ministry of Education of China for Introducing Talents of Discipline to Universities (No.B16009)+1 种基金the Fundamental Research Funds for the Central Universities in China (No.N2201008)Hebei Natural Science Foundation (No.F2020501040)。
文摘Phenylacetic acid(PAA)is a primary raw material for illegal Methamphetamine(MATM)synthesis under the strong precursor chemicals supervisions of safrole and isosafrole.Therefore,trace detection of PAA at ultra-low concentration is a strategic technique and an urgent issue in the field of drug control.In this paper,trace determination of PAA at sub-nmol-L-1 concentration level is achieved by hydrogen bond adsorption and electrochemical catalysis through the prepared aminated SiO_(2)nanoparticles(SiO_(2)-NH_(2) NPs)and MoS_(2) nanosheets(NSs)modified glassy carbon electrode(GCE).The prepared MoS_(2) NS s/SiO_(2)-NH_(2) NPs modified electrode represents a detecting limit of 0.0989 nmol·L^(-1)and an obvious increasing linear range before the concentration increasement up to 60 nmol·L^(-1)in square wave voltammetry(SWV)responses of PAA.The SWV response of the modified electrode to PAA in the concentration range within 100 nmol·L^(-1)is higher than phenol,acetic acid(HOAc)and benzoic Acid(BEN).This electrochemical method for trace detection of PAA in aqueous solution with desired performance provides a feasible scheme for the detection of other drugs and aromatic precursor chemicals.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51672174,51779139,51772190,and 51972210)the Advanced Energy Material and Technology Center of Shanghai Jiao Tong University,China.
文摘MoS_(2)is a promising electrocatalyst for hydrogen evolution reaction and a good candidate for cocatalyst to enhance the photoelectrochemical(PEC)performance of Si-based photoelectrode in aqueous electrolytes.The main challenge lies in the optimization of the microstructure of MoS_(2),to improve its catalytic activity and to construct a mechanically and chemically stable cocatalyst/Si photocathode.In this paper,a highly-ordered mesoporous MoS_(2)was synthesized and decorated onto a TiO_(2)protected p-silicon substrate.An additional TiO_(2)necking was introduced to strengthen the bonding between the MoS_(2)particles and the TiO_(2)layer.This meso-MoS_(2)/TiO_(2)/p-Si hybrid photocathode exhibited significantly enhanced PEC performance,where an onset potential of+0.06 V(versus RHE)and a current density of-1.8 mA/cm^(2)at 0 V(versus RHE)with a Faradaic efficiency close to 100%was achieved in 0.5 mol/L H_(2)SO_(4).Additionally,this meso-MoS_(2)/TiO_(2)/p-Si photocathode showed an excellent PEC ability and durability in alkaline media.This paper provides a promising strategy to enhance and protect the photocathode through high-performance surface cocatalysts.
