Electrocatalysis is key to improving energy efficiency,reducing carbon emissions,and providing a sustainable way of meeting global energy needs.Therefore,elucidating electrochemical reaction mechanisms at the electrol...Electrocatalysis is key to improving energy efficiency,reducing carbon emissions,and providing a sustainable way of meeting global energy needs.Therefore,elucidating electrochemical reaction mechanisms at the electrolyte/electrode interfaces is essential for developing advanced renewable energy technologies.However,the direct probing of real-time interfacial changes,i.e.,the surface intermediates,chemical environment,and electronic structure,under operating conditions is challenging and necessitates the use of in situ methods.Herein,we present a new lab-based instrument commissioned to perform in situ chemical analysis at liquid/solid interfaces using ambient pressure X-ray photoelectron spectroscopy(APXPS).This setup takes advantage of a chromium source of tender X-rays and is designed to study liquid/solid interfaces by the“dip and pull”method.Each of the main components was carefully described,and the results of performance tests are presented.Using a three-electrode setup,the system can probe the intermediate species and potential shifts across the liquid electrolyte/solid electrode interface.In addition,we demonstrate how this system allows the study of interfacial changes at gas/solid interfaces using a case study:a sodium–oxygen model battery.However,the use of APXPS in electrochemical studies is still in the early stages,so we summarize the current challenges and some developmental frontiers.Despite the challenges,we expect that joint efforts to improve instruments and the electrochemical setup will enable us to obtain a better understanding of the composition–reactivity relationship at electrochemical interfaces under realistic reaction conditions.展开更多
The effects of a pulsed magnetic field on the solidified microstructure of an AZ31 magnesium alloy were investigated.The experimental results show that the remarkable microstructural refinement is achieved when the pu...The effects of a pulsed magnetic field on the solidified microstructure of an AZ31 magnesium alloy were investigated.The experimental results show that the remarkable microstructural refinement is achieved when the pulsed magnetic field is applied to the solidification of the AZ31 alloy.The average grain size of the as-cast microstructure of the AZ31 alloy is refined to 107 μm.By quenching the AZ31 alloy, the different primary α-Mg microstructures are preserved during the course of solidification.The microstructure evolution reveals that the primary α-Mg generates and grows in globular shape with pulsed magnetic field, contrast with the dendritic shape without pulsed magnetic field.The pulsed magnetic field causes melt convection during solidification, which makes the temperature of the whole melt homogenized, and produces an undercooling zone in front of the liquid/solid interface, which makes the nucleation rate increased and big dendrites prohibited.In addition, the Joule heat effect induced in the melt also strengthens the grain refinement effect and spheroidization of dendrite arms.展开更多
The molecular scales behavior of interracial water at the solid/liquid interfaces is of a fundamental significance in a diverse set of technical and scientific contexts, ranging from the efficiency of oil mining to th...The molecular scales behavior of interracial water at the solid/liquid interfaces is of a fundamental significance in a diverse set of technical and scientific contexts, ranging from the efficiency of oil mining to the activity of biological molecules. Recently, it has become recognized that, both the physical interactions and the surface morphology have significant impact on the behavior of inter- facial water, including the water structures as well as the wetting properties of the surface. In this review, we summarize some of recent advances in the atom-level pictures of the interfacial water, which exhibits the ordered character on various solid surfaces at room or cryogenic temperature. Special focus has been devoted to the wetting phenomenon of ＂ordered water monolayer that does not completely wet water＂ and the underlying mechanism on model and some real solid surfaces at room temperature. The possible applications of this phenomenon are also discussed.展开更多
文摘Electrocatalysis is key to improving energy efficiency,reducing carbon emissions,and providing a sustainable way of meeting global energy needs.Therefore,elucidating electrochemical reaction mechanisms at the electrolyte/electrode interfaces is essential for developing advanced renewable energy technologies.However,the direct probing of real-time interfacial changes,i.e.,the surface intermediates,chemical environment,and electronic structure,under operating conditions is challenging and necessitates the use of in situ methods.Herein,we present a new lab-based instrument commissioned to perform in situ chemical analysis at liquid/solid interfaces using ambient pressure X-ray photoelectron spectroscopy(APXPS).This setup takes advantage of a chromium source of tender X-rays and is designed to study liquid/solid interfaces by the“dip and pull”method.Each of the main components was carefully described,and the results of performance tests are presented.Using a three-electrode setup,the system can probe the intermediate species and potential shifts across the liquid electrolyte/solid electrode interface.In addition,we demonstrate how this system allows the study of interfacial changes at gas/solid interfaces using a case study:a sodium–oxygen model battery.However,the use of APXPS in electrochemical studies is still in the early stages,so we summarize the current challenges and some developmental frontiers.Despite the challenges,we expect that joint efforts to improve instruments and the electrochemical setup will enable us to obtain a better understanding of the composition–reactivity relationship at electrochemical interfaces under realistic reaction conditions.
基金Project(ZC304009103) supported by the Doctoral Fund of Zhejiang Normal University,ChinaProject(KYJ06Y09157) supported by School-level Project of Zhejiang Normal University,China
文摘The effects of a pulsed magnetic field on the solidified microstructure of an AZ31 magnesium alloy were investigated.The experimental results show that the remarkable microstructural refinement is achieved when the pulsed magnetic field is applied to the solidification of the AZ31 alloy.The average grain size of the as-cast microstructure of the AZ31 alloy is refined to 107 μm.By quenching the AZ31 alloy, the different primary α-Mg microstructures are preserved during the course of solidification.The microstructure evolution reveals that the primary α-Mg generates and grows in globular shape with pulsed magnetic field, contrast with the dendritic shape without pulsed magnetic field.The pulsed magnetic field causes melt convection during solidification, which makes the temperature of the whole melt homogenized, and produces an undercooling zone in front of the liquid/solid interface, which makes the nucleation rate increased and big dendrites prohibited.In addition, the Joule heat effect induced in the melt also strengthens the grain refinement effect and spheroidization of dendrite arms.
基金supported by the National Natural Science Foundation of China (Nos. 11290164 and 11204341)the Knowledge Innovation Program of SINAP+1 种基金the Knowledge Innovation Program of the Chinese Academy of Sciences,Shanghai Supercomputer Center of ChinaSupercomputing Center of Chinese Academy of Sciences
文摘The molecular scales behavior of interracial water at the solid/liquid interfaces is of a fundamental significance in a diverse set of technical and scientific contexts, ranging from the efficiency of oil mining to the activity of biological molecules. Recently, it has become recognized that, both the physical interactions and the surface morphology have significant impact on the behavior of inter- facial water, including the water structures as well as the wetting properties of the surface. In this review, we summarize some of recent advances in the atom-level pictures of the interfacial water, which exhibits the ordered character on various solid surfaces at room or cryogenic temperature. Special focus has been devoted to the wetting phenomenon of ＂ordered water monolayer that does not completely wet water＂ and the underlying mechanism on model and some real solid surfaces at room temperature. The possible applications of this phenomenon are also discussed.
