The effects of Pb^2+concentration,current density,deposition time and temperature on Pb deposit structure were investigated.In lower Pb^2+concentration(~0.15 mol/L),carambola-like 3D-Pb structure was constructed,while...The effects of Pb^2+concentration,current density,deposition time and temperature on Pb deposit structure were investigated.In lower Pb^2+concentration(~0.15 mol/L),carambola-like 3D-Pb structure was constructed,while in higher Pb2+concentration(≥0.30 mol/L),Pb deposits exhibited pyramid-like structure.Furthermore,the oxide layer and anodic potential of carambola-shaped 3D-Pb(Cara-Pb)and pyramid-shaped 3D-Pb(Pyra-Pb)anodes were investigated and compared with those of fresh Pb anode.After 72 h galvanostatic electrolysis(50 mA/cm2)in 160 g/L H2SO4 solution,the oxide layer on Pyra-Pb was much thicker than that on Cara-Pb and Pb anodes,which remarkably relieved intercrystalline corrosion of the metallic substrate.Additionally,the oxide layer on Pyra-Pb anode presented a larger surface area and higher PbO2 content.Hence,Pyra-Pb anode showed a 40 m V lower anodic potential compared to Cara-Pb and Pb anodes.In sum,Pyra-Pb anode had a potential to decrease energy consumption and prolong the life span of traditional Pb anode.展开更多
Television as one of the popular culture media plays an important role in the development of students' personality and knowledge because it provides countless information and entertainment that can enhance their know...Television as one of the popular culture media plays an important role in the development of students' personality and knowledge because it provides countless information and entertainment that can enhance their knowledge as the viewers. This study was conducted to give an idea whether television viewing and parental attention can assist students to take a decision of choosing major at the senior high school. This study used descriptive method which analyzed the correlation among television viewing, parental attention, and the students' motivation to choose a major. The sample of this study consisted of 100 students of the state senior high school in Malang, East Java. The finding shows that there is no correlation among television viewing, parental attention, and the students' motivation to choose major at the senior high school. In other words, the possibility of choosing the major can be attributed to some other factors such as interest, talent, aspiration, and other expectation to achieve their goals展开更多
Interfaces play critical roles in electronic devices and provide great diversity of film morphology and device performance.We retrospect the substrate mediated vacuum film growth of benchmark high mobility material 2,...Interfaces play critical roles in electronic devices and provide great diversity of film morphology and device performance.We retrospect the substrate mediated vacuum film growth of benchmark high mobility material 2,7-dioctyl[1]benzothieno[3,2-b]benzothiophene(C8-BTBT)and the interface electronic structures.The film growth of C8-BTBT molecules is diversified depending on the substrate-molecule and molecule-molecule interactions.On atomic smooth substrates C8-BTBT film grows in layer-by-layer mode while on coarse substrate it grows in islands mode.The initial molecular layer at dielectric,semiconductor and conductive substrates displays slight different lattice structure.The initial molecule orientation depends on the substrate and will gradually change to standing up configuration as in bulk phase.C8-BTBT behaves as electron donor when contacting with dielectric and stable conductive materials.This usually induces a dipole layer pointing to C8-BTBT and an upward bend bending in C8-BTBT side toward the interface.Although it is air stable,C8-BTBT is chemically reactive with some transition metals and compounds.The orientation change from lying down to standing up in the film usually leads to decrease of ionization potential.The article provides insights to the interface physical and chemical processes and suggestions for optimal design and fabrication of C8-BTBT based devices.展开更多
Photodegradation of organic pollutants over semiconductor catalysts is considered to be a viable method for wastewater treatment.Of the different semiconductor photocatalysts,ZnO has been widely used for the photodegr...Photodegradation of organic pollutants over semiconductor catalysts is considered to be a viable method for wastewater treatment.Of the different semiconductor photocatalysts,ZnO has been widely used for the photodegradation of organic pollutants.Meanwhile,graphene is being actively investigated as a cocatalyst for such processes.The high carrier transport rate of graphene can favor the transfer of photoexcited electrons,while the increased specific surface area provides adsorption sites for the organic effluent molecules,thereby improving overall photocatalytic activity.Therefore,in this study,Pt–ZnO–reduced graphene oxide(RGO)rods with different RGO contents are synthesize during a novel Pt-induced electrochemical method,where ZnjZnO acts as the anode and PtjH2OjH2acts as the cathode.The photocatalytic degradation activity of the Pt–ZnO–RGO rods is remarkably improved under UV–visible light irradiation,with the optimum loading RGO content of 1 wt%.展开更多
We present a study of the electric field effect on electrochemically grown ultrathin, straight platinum nanowires with minimum diameter of 15 nm and length in the micrometer range, synthesized on a silicon oxide subst...We present a study of the electric field effect on electrochemically grown ultrathin, straight platinum nanowires with minimum diameter of 15 nm and length in the micrometer range, synthesized on a silicon oxide substrate between metal electrodes in H2PtC16 solution. The influence of the concentration of the platinum- containing acid and the frequency of the applied voltage on the diameter of the nanowires is discussed with a corresponding theoretical analysis. We demonstrate for the first time that the electric field profile, provided by the specific geometry of the metal electrodes, dramatically influences the growth and morphology of the nanowires. Finally, we provide guidelines for the controlled fabrication and contacting of straight, ultrathin metal wires, eliminating branching and dendritic growth, which is one of the main shortcomings of the current bottom-up nanotechnology. The proposed concept of self-assembly of thin nanowires, influenced by the electric field, potentially represents a new route for guided nanocontacting via smart design of the electrode geometry. The possible applications reach from nanoelectronics to gas sensors and biosensors.展开更多
Synthesis of shape-controlled Pt nanocrystals is substantial and important for enhancing chemical and electrochemical reactions.However,the removal of capping agents,shape-controlling chemicals,on Pt surfaces is essen...Synthesis of shape-controlled Pt nanocrystals is substantial and important for enhancing chemical and electrochemical reactions.However,the removal of capping agents,shape-controlling chemicals,on Pt surfaces is essential prior to conducting the catalytic reactions.Here we report a facile one-pot synthesis of Pt nanocubes directly grown on carbon supports(Pt nanocubes/C) with modulating the kinetic reaction factors for shaping the nanocrystals,but without adding any capping agents for preserving the clean Pt surfaces.Well-dispersed Pt nanocubes/C shows enhanced activity and long-term stability toward methanol oxidation reaction compared to the commercial Pt/C catalyst.展开更多
Laser was coupled into an optical fiber,on which covered a layer of well-aligned carbon nanotubes(CNTs)serving as cathode,to tune the field emission of the cathode.CNT arrays as field emission cathode were synthesized...Laser was coupled into an optical fiber,on which covered a layer of well-aligned carbon nanotubes(CNTs)serving as cathode,to tune the field emission of the cathode.CNT arrays as field emission cathode were synthesized by chemical vapor deposition(CVD)on a naked fiber core.When the laser was coupled into the fiber,the turn-on voltage(Vto at a current density of 1 mA cm?2)decreased from 1.0 to 0.9 kV and the emission current density increased from 0.83 mA cm?2(at a 1 kV bias voltage)to3.04 mA cm?2 on 40μm diameter fiber.A photon absorption mechanism is attributed to the field emission improvement.The estimated effective work function of CNT arrays on the optical fiber decrease from 4.89 to 4.29 eV.The results show the possibility of constructing a waveguide type laser modulated field emission cathode.展开更多
Large-scale single crystals have potential applications in many fields,such as in ferroelectric and photoelectric energy conversion devices.Perovskite oxynitrides have also attracted attention in photoelectrochemical ...Large-scale single crystals have potential applications in many fields,such as in ferroelectric and photoelectric energy conversion devices.Perovskite oxynitrides have also attracted attention in photoelectrochemical water splitting systems because of their high theoretical solar-to-hydrogen efficiencies.Nevertheless,the synthesis of perovskite oxynitride single crystals requires the coupling of cation exchange and ammonization processes,which is exceptionally challenging.The present study demonstrates an inorganic vapor method that provides,for the first time ever,high-quality epitaxial perovskite SrTaO_(2)N single crystals on the centimeter scale.Assessments using Raman spectroscopy,crystal structure analysis and density functional theory determined that the conversion mechanism followed a topotactic transition mode.Compared with conventional SrTaO_(2)N particle-assembled films,the SrTaO_(2)N single crystals made in this work were free of interparticle interfaces and grain boundaries,which exhibited extremely high performance during photoelectrochemical water oxidation.In particular,these SrTaO_(2)N single crystals showed the highest photocurrent density at 0.6 V vs.RHE(1.20 mA cm^(−2)) and the highest photocurrent filling factor(47.6%)reported to date,together with a low onset potential(0.35 V vs.RHE).This onset potential was 200 mV less than that of the reported in situ SrTaO_(2)N film,and the photocurrent fill factor was improved by 2 to 3 times.展开更多
Controllable growth of high-quality hybrid nanostructures is highly desirable for the fabrication of hierarchical, complex and multifunctional devices. Here, PdAg alloys have been controllably grown at different locat...Controllable growth of high-quality hybrid nanostructures is highly desirable for the fabrication of hierarchical, complex and multifunctional devices. Here, PdAg alloys have been controllably grown at different locations on gold nanorods, producing dumbbell-like nanostructures with PdAg at the ends of the gold nanorods or branched nanostructures with PdAg grown almost perpendicular to the gold nanorods. The nucleation sites of PdAg alloys on the gold nanorods can be effectively tuned by varying the concentrations of H2PdC14, AgNO3 and cetyltrimethylammonium bromide (CTAB). The dumbbell-like and branched nanostructures were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), line-scanning energy-dispersive X-ray spectros-copy (EDS), X-ray photoelectron spectroscopy (XPS) and UV-Vis absorption spectroscopy. Their electrocatalytic performance was evaluated using ethanol oxidation as a probe reaction. The dumbbelMike nanostructures show a better anti-poisoning performance, but a worse electrochemical activity than the branched ones. The results provide guidelines for the controlled growth of complicated nanostructures for either fundamental studies or potential applications.展开更多
Cd3As2 was recently identified as a novel three-dimensional (3D) topological semimetal hosting the long-pursuing 3D Dirac Fermion. Crystals of Cd3As2 grown preferentially along the [100] and [112] directions were ob...Cd3As2 was recently identified as a novel three-dimensional (3D) topological semimetal hosting the long-pursuing 3D Dirac Fermion. Crystals of Cd3As2 grown preferentially along the [100] and [112] directions were obtained through the modified chemical vapor transfer growth method, thus allowing the examination of transport anisotropy. The resistivity and magnetore- sistance (MR) are basically linear with respect to magnetic field (H) in the measured temperature range of 2-300 K irrespective of the directions. The linear resistivity and MR are significantly anisotropic not only along [100] and [112] directions but also with respect to tilt angle between the growth directions and H, thus providing transport signatures of the 3D Dirac Fermion as well as the possible linear and anisotropic change of Weyl Fermi surface in H. Very large MR along the [100] direction is observed, even approaching 3100% at 2 K and 14 kOe (10e = 79.5775 A m^-l). The results would be helpful in renewing interest in studying emergent phenomena arising from bulk 3D Dirac Fermion as well as in paving the way for Cd3As2 to be used in magnetoelectronic sensors.展开更多
基金National Natural Science Foundation of China(No.10647105,No.60676059)Key Project of National Natural Science Foundation of China(No.60336020,No.50532050)+1 种基金"973"Program(No.2006CB604906)CAS Innovation Program,the National Natural Science Foundation of China(No.60429403,No.60506014,No.50402016,No.10674133)
基金Project(51704130)supported by the National Natural Science Foundation of ChinaProject(GK-201905)supported by the Research Fund of State Key Laboratory of Rare Metals Separation and Comprehensive Utilization,ChinaProject(jxxjbs16026)supported by the Doctoral Scientific Research Foundation of Jiangxi University of Science and Technology,China
文摘The effects of Pb^2+concentration,current density,deposition time and temperature on Pb deposit structure were investigated.In lower Pb^2+concentration(~0.15 mol/L),carambola-like 3D-Pb structure was constructed,while in higher Pb2+concentration(≥0.30 mol/L),Pb deposits exhibited pyramid-like structure.Furthermore,the oxide layer and anodic potential of carambola-shaped 3D-Pb(Cara-Pb)and pyramid-shaped 3D-Pb(Pyra-Pb)anodes were investigated and compared with those of fresh Pb anode.After 72 h galvanostatic electrolysis(50 mA/cm2)in 160 g/L H2SO4 solution,the oxide layer on Pyra-Pb was much thicker than that on Cara-Pb and Pb anodes,which remarkably relieved intercrystalline corrosion of the metallic substrate.Additionally,the oxide layer on Pyra-Pb anode presented a larger surface area and higher PbO2 content.Hence,Pyra-Pb anode showed a 40 m V lower anodic potential compared to Cara-Pb and Pb anodes.In sum,Pyra-Pb anode had a potential to decrease energy consumption and prolong the life span of traditional Pb anode.
文摘Television as one of the popular culture media plays an important role in the development of students' personality and knowledge because it provides countless information and entertainment that can enhance their knowledge as the viewers. This study was conducted to give an idea whether television viewing and parental attention can assist students to take a decision of choosing major at the senior high school. This study used descriptive method which analyzed the correlation among television viewing, parental attention, and the students' motivation to choose a major. The sample of this study consisted of 100 students of the state senior high school in Malang, East Java. The finding shows that there is no correlation among television viewing, parental attention, and the students' motivation to choose major at the senior high school. In other words, the possibility of choosing the major can be attributed to some other factors such as interest, talent, aspiration, and other expectation to achieve their goals
基金Project(2017YFA0206602)supported in part by the National Key Research and Development Program of China。
文摘Interfaces play critical roles in electronic devices and provide great diversity of film morphology and device performance.We retrospect the substrate mediated vacuum film growth of benchmark high mobility material 2,7-dioctyl[1]benzothieno[3,2-b]benzothiophene(C8-BTBT)and the interface electronic structures.The film growth of C8-BTBT molecules is diversified depending on the substrate-molecule and molecule-molecule interactions.On atomic smooth substrates C8-BTBT film grows in layer-by-layer mode while on coarse substrate it grows in islands mode.The initial molecular layer at dielectric,semiconductor and conductive substrates displays slight different lattice structure.The initial molecule orientation depends on the substrate and will gradually change to standing up configuration as in bulk phase.C8-BTBT behaves as electron donor when contacting with dielectric and stable conductive materials.This usually induces a dipole layer pointing to C8-BTBT and an upward bend bending in C8-BTBT side toward the interface.Although it is air stable,C8-BTBT is chemically reactive with some transition metals and compounds.The orientation change from lying down to standing up in the film usually leads to decrease of ionization potential.The article provides insights to the interface physical and chemical processes and suggestions for optimal design and fabrication of C8-BTBT based devices.
基金supported by the National Natural Science Foundation of China (51202105,21203088,21263016)Science and Technology Project of Education Department of Jiangxi Province (GJJ12046)+1 种基金the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure (SKL201205SIC)support from the Institute of Metal Research,Chinese Academy of Sciences
文摘Photodegradation of organic pollutants over semiconductor catalysts is considered to be a viable method for wastewater treatment.Of the different semiconductor photocatalysts,ZnO has been widely used for the photodegradation of organic pollutants.Meanwhile,graphene is being actively investigated as a cocatalyst for such processes.The high carrier transport rate of graphene can favor the transfer of photoexcited electrons,while the increased specific surface area provides adsorption sites for the organic effluent molecules,thereby improving overall photocatalytic activity.Therefore,in this study,Pt–ZnO–reduced graphene oxide(RGO)rods with different RGO contents are synthesize during a novel Pt-induced electrochemical method,where ZnjZnO acts as the anode and PtjH2OjH2acts as the cathode.The photocatalytic degradation activity of the Pt–ZnO–RGO rods is remarkably improved under UV–visible light irradiation,with the optimum loading RGO content of 1 wt%.
文摘We present a study of the electric field effect on electrochemically grown ultrathin, straight platinum nanowires with minimum diameter of 15 nm and length in the micrometer range, synthesized on a silicon oxide substrate between metal electrodes in H2PtC16 solution. The influence of the concentration of the platinum- containing acid and the frequency of the applied voltage on the diameter of the nanowires is discussed with a corresponding theoretical analysis. We demonstrate for the first time that the electric field profile, provided by the specific geometry of the metal electrodes, dramatically influences the growth and morphology of the nanowires. Finally, we provide guidelines for the controlled fabrication and contacting of straight, ultrathin metal wires, eliminating branching and dendritic growth, which is one of the main shortcomings of the current bottom-up nanotechnology. The proposed concept of self-assembly of thin nanowires, influenced by the electric field, potentially represents a new route for guided nanocontacting via smart design of the electrode geometry. The possible applications reach from nanoelectronics to gas sensors and biosensors.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2015R1D1A3A01019467,NRF2017R1D1A1B03031892) and KBSI(D37614)
文摘Synthesis of shape-controlled Pt nanocrystals is substantial and important for enhancing chemical and electrochemical reactions.However,the removal of capping agents,shape-controlling chemicals,on Pt surfaces is essential prior to conducting the catalytic reactions.Here we report a facile one-pot synthesis of Pt nanocubes directly grown on carbon supports(Pt nanocubes/C) with modulating the kinetic reaction factors for shaping the nanocrystals,but without adding any capping agents for preserving the clean Pt surfaces.Well-dispersed Pt nanocubes/C shows enhanced activity and long-term stability toward methanol oxidation reaction compared to the commercial Pt/C catalyst.
基金supported by the National Natural Science Foundation of China(Grant Nos.91123018,61172041,61172040,50975226,and 60801022)the National Hi-Tech Research and Development Program of China("863"Project)(Grant No.2008AA03A314)the Fundamental Research Funds for the Central Universities
文摘Laser was coupled into an optical fiber,on which covered a layer of well-aligned carbon nanotubes(CNTs)serving as cathode,to tune the field emission of the cathode.CNT arrays as field emission cathode were synthesized by chemical vapor deposition(CVD)on a naked fiber core.When the laser was coupled into the fiber,the turn-on voltage(Vto at a current density of 1 mA cm?2)decreased from 1.0 to 0.9 kV and the emission current density increased from 0.83 mA cm?2(at a 1 kV bias voltage)to3.04 mA cm?2 on 40μm diameter fiber.A photon absorption mechanism is attributed to the field emission improvement.The estimated effective work function of CNT arrays on the optical fiber decrease from 4.89 to 4.29 eV.The results show the possibility of constructing a waveguide type laser modulated field emission cathode.
基金supported by the National Key Research and Development Program of China(2018YFA0209303)the National Natural Science Foundation of China(22025202 and 51972165)Natural Science Foundation of Jiangsu Province(BK20202003)。
文摘Large-scale single crystals have potential applications in many fields,such as in ferroelectric and photoelectric energy conversion devices.Perovskite oxynitrides have also attracted attention in photoelectrochemical water splitting systems because of their high theoretical solar-to-hydrogen efficiencies.Nevertheless,the synthesis of perovskite oxynitride single crystals requires the coupling of cation exchange and ammonization processes,which is exceptionally challenging.The present study demonstrates an inorganic vapor method that provides,for the first time ever,high-quality epitaxial perovskite SrTaO_(2)N single crystals on the centimeter scale.Assessments using Raman spectroscopy,crystal structure analysis and density functional theory determined that the conversion mechanism followed a topotactic transition mode.Compared with conventional SrTaO_(2)N particle-assembled films,the SrTaO_(2)N single crystals made in this work were free of interparticle interfaces and grain boundaries,which exhibited extremely high performance during photoelectrochemical water oxidation.In particular,these SrTaO_(2)N single crystals showed the highest photocurrent density at 0.6 V vs.RHE(1.20 mA cm^(−2)) and the highest photocurrent filling factor(47.6%)reported to date,together with a low onset potential(0.35 V vs.RHE).This onset potential was 200 mV less than that of the reported in situ SrTaO_(2)N film,and the photocurrent fill factor was improved by 2 to 3 times.
基金This work was supported by the Natural Science Foundation of China (Nos. 20801019, 21071055, 21172076), New Century Excellent Talents in University (No. NCET-10-0369), Shandong Provincial Natural Science Foundation for Distinguished Young Scholar (No. JQ201205), Independent Innovation Foundations of Shandong University (No. 2012 ZD007), new-faculty start-up funding in Shandong University and Key Laboratory of Fuel Cell Technology of Guangdong Province.
文摘Controllable growth of high-quality hybrid nanostructures is highly desirable for the fabrication of hierarchical, complex and multifunctional devices. Here, PdAg alloys have been controllably grown at different locations on gold nanorods, producing dumbbell-like nanostructures with PdAg at the ends of the gold nanorods or branched nanostructures with PdAg grown almost perpendicular to the gold nanorods. The nucleation sites of PdAg alloys on the gold nanorods can be effectively tuned by varying the concentrations of H2PdC14, AgNO3 and cetyltrimethylammonium bromide (CTAB). The dumbbell-like and branched nanostructures were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), line-scanning energy-dispersive X-ray spectros-copy (EDS), X-ray photoelectron spectroscopy (XPS) and UV-Vis absorption spectroscopy. Their electrocatalytic performance was evaluated using ethanol oxidation as a probe reaction. The dumbbelMike nanostructures show a better anti-poisoning performance, but a worse electrochemical activity than the branched ones. The results provide guidelines for the controlled growth of complicated nanostructures for either fundamental studies or potential applications.
基金supported by the Ministry of Science and Technology of China(Grant Nos.2011CBA00110 and 2010CB923001)the National Natural Science Foundation of China(Grant Nos.11274367 and 61274017)Zhejiang SciTech Univeristy 521 talent project and Chinese Academy of Sciences
文摘Cd3As2 was recently identified as a novel three-dimensional (3D) topological semimetal hosting the long-pursuing 3D Dirac Fermion. Crystals of Cd3As2 grown preferentially along the [100] and [112] directions were obtained through the modified chemical vapor transfer growth method, thus allowing the examination of transport anisotropy. The resistivity and magnetore- sistance (MR) are basically linear with respect to magnetic field (H) in the measured temperature range of 2-300 K irrespective of the directions. The linear resistivity and MR are significantly anisotropic not only along [100] and [112] directions but also with respect to tilt angle between the growth directions and H, thus providing transport signatures of the 3D Dirac Fermion as well as the possible linear and anisotropic change of Weyl Fermi surface in H. Very large MR along the [100] direction is observed, even approaching 3100% at 2 K and 14 kOe (10e = 79.5775 A m^-l). The results would be helpful in renewing interest in studying emergent phenomena arising from bulk 3D Dirac Fermion as well as in paving the way for Cd3As2 to be used in magnetoelectronic sensors.