Layout of the In Situ XPS Measurement System
A research group led by Prof. Dr. Kohei Uosaki, Research Manager of the Batteries and Fuel Cells Field at the Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN) of the National Institute for Materials Science (NIMS) and Dr. Takuya Masuda, Researcher of the Precursory Research for Embryonic Science and Technology (PRESTO) program at the Japan Science and Technology Agency (JST), in collaboration with NIMS International Center for Materials Nanoarchitectonics (WPI-MANA) and the Synchrotron X-ray Station at SPring-8, developed a new measurement system using high-energy X-rays of SPring-8 and a silicon (Si) thin-membrane window. Through this achievement, the group succeeded for the first time in the world in tracking electrochemical reactions at solid/liquid interfaces in situ by X-ray photoelectron spectroscopy (XPS), which could only be used for measurement in a vacuum in the past.
A solid/liquid interface is an important part that converts and uses energy in familiar energy devices, such as fuel cells and solar cells. Recent research and development which aims to maximize the efficiency of energy use faces the need to break away from materials development dependent on empirical rules and to adopt clear evaluation methods that enable strategic materials design. Accordingly, there has been a strong desire for methods to directly observe and measure the dynamic behavior of reactions at solid/liquid interfaces in the environment where the reactions are taking place (in situ). Meanwhile, XPS is a method to investigate the surface species and oxidation states of the surface of a substance by irradiating the substance with X-rays and analyzing the energy of the photoelectrons emitted from the elements on the surface. Conventionally, XPS could only be used for measurement in a vacuum, and could not be used to directly observe the reactions at solid/liquid interfaces in situ.
The research group succeeded in observing the electrochemical reactions at a solid/liquid interface in a non-vacuum environment in situ by having high-energy synchrotron X-rays of SPring-8 penetrate through a thin Si membrane window with a thickness of 15 nm. Specifically, the group developed a measurement system that uses a thin Si membrane as a window for transmitting X-rays and photoelectrons, as a barrier separating a vacuum and a liquid, and as an electrode for electrochemical reactions, and uses the high-energy synchrotron X-rays of SPring-8 to detect, on the vacuum side (through the thin membrane), the photoelectrons that have been emitted at the interface between the thin Si membrane window (solid) and the liquid. With this system, the group succeeded in in situ observation of potential-induced Si oxide growth in water.
The research results are expected to further elucidate the process at solid/liquid interfaces of major energy devices such as rechargeable batteries and fuel cells. At the same time, they are expected to contribute to the development and better performance of important parts such as cell electrodes and catalyst materials as a result of clarifying the reaction mechanism and problems in existing materials. In particular, quantitative investigation of the composition and oxidation states of interfaces, which was difficult in the past, becomes possible, which helps illuminate the deterioration mechanism of electrodes and electrolytes through identification of side reactions and the products of the reactions. Also, since XPS has been used for materials design and development in diverse fields including the industrial field and the medical field, the research results are expected to contribute to elucidating the mechanism of a broad range of phenomena in which interface reactions play an important role in those fields.
This research was conducted as part of the “Program for Development of Environmental Technology using Nanotechnology” entrusted by the Ministry of Education, Culture, Sports, Science and Technology, and as part of the “Phase Interfaces for Highly Efficient Energy Utilization” research domain (Research Supervisor: Nobuhide Kasagi) of Individual Type Research (PRESTO) of the JST Strategic Basic Research Program, and the research results were published in the online preliminary edition of Applied Physics Letters, an applied physics journal published by the American Institute of Physics, at 3:00 a.m., September 13, 2013 (JST).
Mikiko Tanifuji | Research asia research news
Further reports about: > Materials Science > NIMS > Photoelectron > Synchrotron > X-ray microscopy > X-ray photoelectron spectroscopy > X-rays > chemical reaction > electrochemical reaction > energy devices > information technology > liquid interfaces > materials design > photoelectron spectroscopy > solar cell > spectroscopy
Superconductivity research reveals potential new state of matter
17.08.2017 | DOE/Los Alamos National Laboratory
Spray-on electric rainbows: Making safer electrochromic inks
17.08.2017 | Georgia Institute of Technology
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
17.08.2017 | Physics and Astronomy
17.08.2017 | Earth Sciences
17.08.2017 | Physics and Astronomy