ESCA applied to liquids

Siegbahn, Hans; Siegbahn, Kai

doi:10.1016/0368-2048(73)80023-4

Cited by 473 publications

(508 citation statements)

References 2 publications

Supporting

Mentioning

479

Contrasting

Unclassified

Order By: Relevance

“…This problem is overcome in ambient pressure XPS (AP-XPS), which allows measurement in the Torr range or above. [18][19] A typical instrument (Figure 1) consists of a highpressure cell/chamber, separated from the electron analyzer-which remains in high vacuum-by a differentially pumped electrostatic lens system and series of apertures. [20][21] Such instruments are found at synchrotrons around the world [22][23][24][25][26][27] and are being increasingly used with lab X-ray sources as well, which will further empower the field in the years to come.…”

Section: Ambient Pressure X-ray Photoelectron Spectroscopymentioning

confidence: 99%

Insights into Electrochemical Reactions from Ambient Pressure Photoelectron Spectroscopy

et al. 2015

View full text Add to dashboard Cite

ConspectusThe understanding of fundamental processes in the bulk and at the interfaces of electrochemical devices is a prerequisite for the development of new technologies with higher efficiency and improved performance. One energy storage scheme of great interest is splitting water to form hydrogen and oxygen gas, and converting back to electrical energy by their subsequent recombination with only water as a by-product. However, kinetic limitations to the rate of oxygen-based electrochemical reactions hamper the efficiency in technologies such as solar fuels, fuel cells, and electrolyzers. For these reactions, the use of metal oxides as electrocatalysts is prevalent due to their stability, low cost, and ability to store oxygen within the lattice. However, due to the inherently convoluted nature of electrochemical and chemical processes in electrochemical systems, it is difficult to isolate and study individual electrochemical processes in a complex system. Therefore in situ characterization tools are required for observing related physical and chemical processes directly at the places where and while they occur, and can help elucidate the mechanisms of charge separation and charge transfer at electrochemical interfaces.X-ray photoelectron spectroscopy (XPS), also known as ESCA (electron spectroscopy for chemical analysis) has been used as a quantitative spectroscopic technique that measures the elemental composition, as well as chemical and electronic state of a material. Building from extensive ex situ characterization of electrochemical systems, initial in situ studies were conducted at (near) UHV conditions (≤10 −6 Torr) to probe solid-state electrochemical systems. However through the integration of differential-pumping stages, XPS can now operate at pressures in the Torr range, comprising a technique called ambient pressure XPS (AP-XPS).In this Account, we briefly review the working principles and current status of AP-XPS. We use several recent in situ studies on model electrochemical components as well as operando studies performed by our groups at the Advanced Light Source (ALS) at Lawrence Berkeley National Lab to illustrate that AP-XPS is both a chemically and electrically specific tool since photoelectrons carry information on both the local chemistry and electrical potentials. The applications of AP-XPS to oxygen electrocatalysis shown in this Account span well defined studies of (1) the oxide/oxygen gas interface, (2) the oxide/water vapor interface, and (3) operando measurements of half and full electrochemical cells. Using 2 specially designed model devices, we can expose and isolate the electrode or interface of interest to the incident X-ray beam and AP-XPS analyzer to relate the electrical potentials to the composition/chemical state of the key components and interfaces. We conclude with an outlook on new developments of AP-XPS endstations, which may provide significant improvement in the observation of dynamics over a wide range of time scale, higher spatial resolution, and improved characteri...

show abstract

Section: Ambient Pressure X-ray Photoelectron Spectroscopymentioning

confidence: 99%

Insights into Electrochemical Reactions from Ambient Pressure Photoelectron Spectroscopy

et al. 2015

View full text Add to dashboard Cite

show abstract

“…In most cases the core levels of the gas phase species are shifted by several eV to higher BE compared to peaks from the condensed species 18 , and therefore gas phase peaks usually do not interfere with the observation of the spectrum from the surface. In cases were gas phase peaks overlap with the signal of the surface the gas phase peaks can be shifted away from the surface peaks by applying a negative bias to the sample, as described in Ref.…”

Section: The Role Of the Gas Phase In Appes Measurementsmentioning

confidence: 99%

Photoelectron spectroscopy under ambient pressure and temperature conditions

Ogletree

Bluhm

Hebenstreit

et al. 2009

Nuclear Instruments and Methods in Physics Research Section A:

238

222

View full text Add to dashboard Cite

We describe the development and applications of novel instrumentation for photoemission spectroscopy of solid or liquid surfaces in the presence of gases under ambient conditions or pressure and temperature. The new instrument overcomes the strong scattering of electrons in gases by the use of an aperture close to the surface followed by a differentially-pumped electrostatic lens system. In addition to the scattering problem, experiments in the presence of condensed water or other liquids require the development of special sample holders to provide localized cooling. We discuss the first two

show abstract

“…Once the electrons pass the plane of the aperture, scattering by gas molecules is greatly reduced. This approach has been used, beginning with Hans Siegbahn and coworkers early designs in the 1970's 10,11,12 , in all ambient pressure XPS instruments that have been designed to date. 13,14,15,16,17,18,19,20,21 A similar approach has been taken in the application of meta-stable impact electron spectroscopy (MIES) 22,23 for the study of surfaces, including liquids, at elevated pressures.…”

Section: Introductionmentioning

confidence: 99%

A combined droplet train and ambient pressure photoemission spectrometer for the investigation of liquid/vapor interfaces

Starr

Wong

Worsnop

et al. 2008

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

We describe a combined ambient pressure photoelectron spectroscopy/droplet train apparatus for investigating the nature and heterogeneous chemistry of liquid/vapor interfaces. In this instrument a liquid droplet train with typical droplet diameters from 50…150 µm is produced by a vibrating orifice aerosol generator (VOAG). The droplets are irradiated by soft X-rays (100…1500 eV) in front of the entrance aperture of a differentially pumped electrostatic lens system that transfers the emitted electrons into a conventional hemispherical electron analyzer.The photoemission experiments are performed at background pressures of up to several Torr, which allows the study of environmentally important liquid/vapor interfaces, in particular aqueous solutions, under equilibrium conditions. The exposure time of the droplet surface to the background gases prior to the XPS measurement can be varied, which will allow future kinetic

show abstract

ESCA applied to liquids

Cited by 473 publications

References 2 publications

Insights into Electrochemical Reactions from Ambient Pressure Photoelectron Spectroscopy

Insights into Electrochemical Reactions from Ambient Pressure Photoelectron Spectroscopy

Photoelectron spectroscopy under ambient pressure and temperature conditions

A combined droplet train and ambient pressure photoemission spectrometer for the investigation of liquid/vapor interfaces

Contact Info

Product

Resources

About