Abstract
We report a new method to probe the solid-liquid interface through the use of a thin liquid layer on a solid surface. An ambient pressure XPS (AP-XPS) endstation that is capable of detecting high kinetic energy photoelectrons (7 keV) at a pressure up to 110 Torr has been constructed and commissioned. Additionally, we have deployed a “dip & pull” method to create a stable nanometers-thick aqueous electrolyte on platinum working electrode surface. Combining the newly constructed AP-XPS system, “dip & pull” approach, with a “tender” X-ray synchrotron source (2 keV–7 keV), we are able to access the interface between liquid and solid dense phases with photoelectrons and directly probe important phenomena occurring at the narrow solid-liquid interface region in an electrochemical system. Using this approach, we have performed electrochemical oxidation of the Pt electrode at an oxygen evolution reaction (OER) potential. Under this potential, we observe the formation of both Pt2+ and Pt4+ interfacial species on the Pt working electrode in situ. We believe this thin-film approach and the use of “tender” AP-XPS highlighted in this study is an innovative new approach to probe this key solid-liquid interface region of electrochemistry.
Highlights
To apply XPS, known as ESCA (Electron Spectroscopy for Chemical Analysis), to liquid and gas phases, Siegbahn et al pioneered the methodology of ambient pressure XPS (AP-XPS) by using a laboratory-based X-ray source in near ambient pressure conditions[2,3]
We report a new method to probe the solid-liquid interface through the use of a thin liquid layer on a solid surface
We will introduce a “dip & pull” method to create a stable nanometers thick thin liquid film on a platinum electrode utilizing a customized three-electrode electrochemistry apparatus. Using this “solid-thin liquid film” system we show experimental evidence validating the thickness of this liquid film and demonstrate this “solid-thin liquid film” system can be used for operando electrochemistry studies by probing Pt oxidation in 6 M KF electrolyte and discover the formation of Pt2+ and Pt4+ interfacial species during oxygen evolution reaction (OER)
Summary
Combining the newly constructed AP-XPS system, “dip & pull” approach, with a “tender” X-ray synchrotron source (2 keV–7 keV), we are able to access the interface between liquid and solid dense phases with photoelectrons and directly probe important phenomena occurring at the narrow solid-liquid interface region in an electrochemical system Using this approach, we have performed electrochemical oxidation of the Pt electrode at an oxygen evolution reaction (OER) potential. We have constructed a new AP-XPS system equipped with a Scienta HiPP-2 electron analyzer and a three-electrode in situ electrochemistry apparatus Combining this new system with a “tender” X-ray synchrotron source (an X-ray region 2 keV to
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
