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 evolution of the surface oxide film along the depth direction of typical aluminum alloy under mediumtemperature brazing was investigated by means of X-ray photoelectron spectroscopy(XPS). For the alloy with Mg con...The evolution of the surface oxide film along the depth direction of typical aluminum alloy under mediumtemperature brazing was investigated by means of X-ray photoelectron spectroscopy(XPS). For the alloy with Mg content below 2.0wt%, whether under cold rolling condition or during medium-temperature brazing process, the enrichment of Mg element on the surface was not detected and the oxide film was pure Al2O3. However, the oxide film grew obviously during medium-temperature brazing process, and the thickness was about 80 nm. For the alloy with Mg content above 2.0wt%, under cold rolling condition, the original surface oxide film was pure Al2O3. However, the Mg element was significantly enriched on the outermost surface during medium-temperature brazing process, and MgO-based oxide film mixed with small amount of MgAl2O4 was formed with a thickness of about 130 nm. The alloying elements of Mn and Si were not enriched on the surface neither under cold rolling condition nor during mediumtemperature brazing process for all the selected aluminum alloy, and the surface oxide film was similar to that of pure aluminum, which was almost entire Al2O3.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Supported by National Natural Science Foundation of China(No.51005163 and No.51275351)Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China
文摘The evolution of the surface oxide film along the depth direction of typical aluminum alloy under mediumtemperature brazing was investigated by means of X-ray photoelectron spectroscopy(XPS). For the alloy with Mg content below 2.0wt%, whether under cold rolling condition or during medium-temperature brazing process, the enrichment of Mg element on the surface was not detected and the oxide film was pure Al2O3. However, the oxide film grew obviously during medium-temperature brazing process, and the thickness was about 80 nm. For the alloy with Mg content above 2.0wt%, under cold rolling condition, the original surface oxide film was pure Al2O3. However, the Mg element was significantly enriched on the outermost surface during medium-temperature brazing process, and MgO-based oxide film mixed with small amount of MgAl2O4 was formed with a thickness of about 130 nm. The alloying elements of Mn and Si were not enriched on the surface neither under cold rolling condition nor during mediumtemperature brazing process for all the selected aluminum alloy, and the surface oxide film was similar to that of pure aluminum, which was almost entire Al2O3.
