The objective of this research is to prepare specially designed surface texture on hard steel surface by electrochemical micromachining (EM) and to incorporate electroless plated Ag/MoS2 solid lubricant coating into t...The objective of this research is to prepare specially designed surface texture on hard steel surface by electrochemical micromachining (EM) and to incorporate electroless plated Ag/MoS2 solid lubricant coating into the dimples of EM textured steel surface to effectively reduce friction and wear of steel-steel contacts. The friction and wear behavior of the Ag/MoS2 solid lubricant coating on EM textured steel surface was evaluated in relation to the size and spacing of the dimples thereon. The microstructure of as-plated Ag/MoS2 solid lubricant coating and the morphology and elemental composition of the worn coating surface and counterface steel surface were analyzed by means of optical microscopy, scanning electron microscopy, and energy dispersive spectrometry. It is found that electroless plated Ag/MoS2 coating is able to greatly reduce the friction and wear of the EM textured steel disc coupled with GCr15 steel ring, mainly because of the formation of solid self-lubricating layer on the EM textured steel surface and of transferred lubricating film on counterface steel surface. The diameter and spacing of the dimples are suggested as 500 μm for acquiring the best wear resistance of the hard steel discs after electrochemical micromachining treatment and electroless plating of Ag/MoS2 solid lubricating coating.展开更多
Highly efficient Ag3PO4/MoS2 nanocomposite photocatalyst was synthe- sized using a wet chemical route with a low weight percentage of highly exfoliated MoS2 （0.1 wt.%） and monodispersed Ag3PO4 nanoparticles （-5.4 n...Highly efficient Ag3PO4/MoS2 nanocomposite photocatalyst was synthe- sized using a wet chemical route with a low weight percentage of highly exfoliated MoS2 （0.1 wt.%） and monodispersed Ag3PO4 nanoparticles （-5.4 nm）. The structural and optical properties of the nanocomposite were studied using various characterization techniques, such as XRD, TEM, Raman and absorption spectroscopy. The composite exhibits markedly enhanced photocatalytic activity with a low lamp power （60 W）. Using this composite, a high kinetic rate constant （k） value of 0.244 min^-1 was found. It was observed that -97.6% of dye degrade over the surface of nanocomposite catalyst within 15 min of illumination. The improved photocatalytic activity of Ag3PO4/MoS2 nanocomposite is attributed to the efficient interfacial charge separation, which was supported by the PL results. Large surface area of MoS2 nanosheets incorporated with well dispersed Ag3PO4 nanoparticles further increases charge separation, contributing to enhanced degradation efficiency. A possible mechanism for charge separation is also discussed.展开更多
Developing well-defined nanostructures with superior surface-enhanced Raman scattering （SERS） performance is a critical and highly desirable goal for the practical applications of SERS in sensing and analysis. Here,...Developing well-defined nanostructures with superior surface-enhanced Raman scattering （SERS） performance is a critical and highly desirable goal for the practical applications of SERS in sensing and analysis. Here, a SERS-active substrate was fabricated by decorating a MoS2 monolayer with Ag nanowire （NW） and nanoparticle （NP） structures, using a spin-coating method. Both experimental and theoretical results indicate that strong SERS signals of rhodamine 6G （R6G） molecules can be achieved at ＂hotspots＂ formed in the Ag NW-Ag NP-MoS2 hybrid structure, with an enhancement factor of 106. The SERS enhancement is found to be strongly polarization dependent. The fabricated SERS substrate also exhibits ultrasensitive detection capabilities with a detection limit of 10-11 M, as well as reliable reproducibility and good stability.展开更多
Semiconductoremetal nanocomposites have been widely investigated to modify the intrinsic properties of materials used for optoelectronic devices and sensing applications.In this study,a method for rapid synthesis of M...Semiconductoremetal nanocomposites have been widely investigated to modify the intrinsic properties of materials used for optoelectronic devices and sensing applications.In this study,a method for rapid synthesis of MoS_(2)-Ag nanocomposites via laser-assisted photoreduction was proposed.For the photoreduction process,we used AgNO_(3)solution as a metal source.Under laser irradiation,Ag ions were easily reduced on MoS_(2)by photo-generated electrons from MoS_(2).The optical properties of MoS_(2)-Ag nanocomposites were easily controlled by simple adjustment of the photoreduction time.To investigate the surface-enhanced Raman scattering(SERS)effect of the MoS_(2)-Ag nanocomposites,the SERS spectra of methylene blue(MB)on MoS_(2)-Ag nanocomposites were measured,and the nanocomposites were found to enhance the Raman scattering intensity of MB up to~106.Therefore,the laser-assisted photoreduction method has great potential for rapid synthesis and optical tuning of semiconductoremetal nanocomposites.展开更多
基金supported by the the National NaturalScience Foundation of China(No.51205001)Foundation for Young Talents in College of Anhui Province(No.2012SQRL083ZD)the Talent Innovation Fund of An-hui Polytechnic University(No.S05305)
文摘The objective of this research is to prepare specially designed surface texture on hard steel surface by electrochemical micromachining (EM) and to incorporate electroless plated Ag/MoS2 solid lubricant coating into the dimples of EM textured steel surface to effectively reduce friction and wear of steel-steel contacts. The friction and wear behavior of the Ag/MoS2 solid lubricant coating on EM textured steel surface was evaluated in relation to the size and spacing of the dimples thereon. The microstructure of as-plated Ag/MoS2 solid lubricant coating and the morphology and elemental composition of the worn coating surface and counterface steel surface were analyzed by means of optical microscopy, scanning electron microscopy, and energy dispersive spectrometry. It is found that electroless plated Ag/MoS2 coating is able to greatly reduce the friction and wear of the EM textured steel disc coupled with GCr15 steel ring, mainly because of the formation of solid self-lubricating layer on the EM textured steel surface and of transferred lubricating film on counterface steel surface. The diameter and spacing of the dimples are suggested as 500 μm for acquiring the best wear resistance of the hard steel discs after electrochemical micromachining treatment and electroless plating of Ag/MoS2 solid lubricating coating.
文摘Highly efficient Ag3PO4/MoS2 nanocomposite photocatalyst was synthe- sized using a wet chemical route with a low weight percentage of highly exfoliated MoS2 （0.1 wt.%） and monodispersed Ag3PO4 nanoparticles （-5.4 nm）. The structural and optical properties of the nanocomposite were studied using various characterization techniques, such as XRD, TEM, Raman and absorption spectroscopy. The composite exhibits markedly enhanced photocatalytic activity with a low lamp power （60 W）. Using this composite, a high kinetic rate constant （k） value of 0.244 min^-1 was found. It was observed that -97.6% of dye degrade over the surface of nanocomposite catalyst within 15 min of illumination. The improved photocatalytic activity of Ag3PO4/MoS2 nanocomposite is attributed to the efficient interfacial charge separation, which was supported by the PL results. Large surface area of MoS2 nanosheets incorporated with well dispersed Ag3PO4 nanoparticles further increases charge separation, contributing to enhanced degradation efficiency. A possible mechanism for charge separation is also discussed.
基金This work was supported by the National Natural Science Foundation of China （No. 11274,395）, the Program for Changjiang Scholars and Innovative Research Team in University （No. IRT13042） and the Open Fund of the Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications （Jinan University）.
文摘Developing well-defined nanostructures with superior surface-enhanced Raman scattering （SERS） performance is a critical and highly desirable goal for the practical applications of SERS in sensing and analysis. Here, a SERS-active substrate was fabricated by decorating a MoS2 monolayer with Ag nanowire （NW） and nanoparticle （NP） structures, using a spin-coating method. Both experimental and theoretical results indicate that strong SERS signals of rhodamine 6G （R6G） molecules can be achieved at ＂hotspots＂ formed in the Ag NW-Ag NP-MoS2 hybrid structure, with an enhancement factor of 106. The SERS enhancement is found to be strongly polarization dependent. The fabricated SERS substrate also exhibits ultrasensitive detection capabilities with a detection limit of 10-11 M, as well as reliable reproducibility and good stability.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT).(NRF-2020R1A2C4002557)It was also supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education.(NRF-2021R1A6A3A13045573)Miri Choi at the KBSI(Chuncheon)is thanked for technical assistance with the FE-TEM analysis.
文摘Semiconductoremetal nanocomposites have been widely investigated to modify the intrinsic properties of materials used for optoelectronic devices and sensing applications.In this study,a method for rapid synthesis of MoS_(2)-Ag nanocomposites via laser-assisted photoreduction was proposed.For the photoreduction process,we used AgNO_(3)solution as a metal source.Under laser irradiation,Ag ions were easily reduced on MoS_(2)by photo-generated electrons from MoS_(2).The optical properties of MoS_(2)-Ag nanocomposites were easily controlled by simple adjustment of the photoreduction time.To investigate the surface-enhanced Raman scattering(SERS)effect of the MoS_(2)-Ag nanocomposites,the SERS spectra of methylene blue(MB)on MoS_(2)-Ag nanocomposites were measured,and the nanocomposites were found to enhance the Raman scattering intensity of MB up to~106.Therefore,the laser-assisted photoreduction method has great potential for rapid synthesis and optical tuning of semiconductoremetal nanocomposites.
