一般財団法人材料科学技術振興財団　MST List of Products and Services

The electrodes of fuel cells have a structure in which Pt particles, serving as the catalyst, are supported on a carbon carrier. For the evaluation of Pt, XPS analysis is effective for state analysis, while TEM observation is useful for morphological observation. These methods can also be used to assess the degradation of Pt catalysts, such as oxidation (poisoning) and aggregation (decrease in specific surface area). By reconstructing images taken from different angles, a three-dimensional image of the Pt particles is obtained.

The electrodes of fuel cells are supported by Pt particles or Pt alloy (such as PtRu) particles on carbon. Due to the fine structure of these catalyst particles, which are on the order of a few nanometers, SEM and TEM analyses are used for morphological observation and compositional analysis. In addition to evaluations in the initial state, degradation after current application has been reported, including modulation of alloy composition, Ru leaching, and an increase in catalyst particle size; high spatial resolution HAADF observation and EDX analysis are very effective for these evaluations. Furthermore, SEM observation allows for the confirmation of the shape of the carbon support and the state of the catalyst particles.

The electrodes of fuel cells are supported by Pt particles or Pt alloy (such as PtRu) particles as catalysts on carbon. Due to the fine structure of these catalyst particles, which are on the order of a few nanometers, SEM and TEM analyses are used for morphological observation and compositional analysis. In addition to evaluations in the initial state, degradation after current application has been reported, including modulation of alloy composition, leaching of Ru, and an increase in the diameter of catalyst particles; HAADF observation and high-resolution EDX analysis are very effective for these evaluations. Furthermore, multi-field observation and analysis enable the assessment of particle size and compositional distribution.

The electrodes of fuel cells have a structure in which catalyst particles are supported on a carbon carrier. Evaluating the state of the carrier and catalyst particles is essential for understanding degradation mechanisms and considering design guidelines. XPS analysis is effective for assessing the state of catalyst poisoning (oxidation). Additionally, SEM and TEM observations are effective for evaluating catalyst agglomeration and particle growth. By combining multiple analytical methods, we propose a multifaceted evaluation.

Solid polymer fuel cells (PEFC) are attracting attention for their high output at room temperature, making them suitable for automotive applications, home cogeneration, and mobile use. This time, we will introduce examples of molecular structure evaluation using TOF-SIMS, bonding state analysis using XPS, and quantitative evaluation of solid polymer electrolyte membranes. Additionally, MST allows for comprehensive evaluation of battery materials using various analytical methods under controlled atmospheric conditions.

Solid polymer electrolyte fuel cells (PEFC) are attracting attention for their high output at room temperature, making them suitable for automotive applications, home cogeneration, and mobile use. In this study, we simulated the degradation of solid polymer electrolyte membranes using Fenton's reagent (a solution of hydrogen peroxide and iron ions) and investigated the degradation byproducts in the solution. Composition information of the degradation byproducts was obtained using LC/MS, while information on the eluted ions was acquired using IC.

In XPS analysis, the binding state evaluation of the material surface is conducted by observing the energy of photoelectrons obtained through X-ray irradiation. It allows for the assessment of whether metal elements are in an oxidized state, and for elements with significant energy shifts (chemical shifts) due to oxidation, it also enables the evaluation of the presence and proportion of multiple valences. Below are the main metal elements and oxides for which multiple valence evaluations are possible.

The electron diffraction method using an electron microscope is classified into three types based on the way the electron beam is incident on the sample. The characteristics of each type and examples of data are presented. It is necessary to choose the appropriate method according to the size of the evaluation object and the analysis purpose.

In-situ XAFS allows for the evaluation of the chemical bonding state and local atomic structure of a sample under controlled conditions, focusing on the gas atmosphere and temperature surrounding the sample. Therefore, it is suitable for cases where state evaluation in special environments, such as catalysts, is necessary. This document presents a case where RuO2 powder was heated from room temperature to 400°C under a reducing atmosphere using in-situ XAFS, capturing the changes in the state of RuO2. From the shape of the spectrum, it was confirmed that RuO2 is reduced to Ru between 100°C and 200°C.

Carbon-supported PtRu (PtRu/C) catalysts are used as anode (fuel electrode) catalysts in fuel cells. There is a demand for reducing the amount of Pt used in order to lower costs, and active research and development is underway. To evaluate the state of the catalyst under fuel cell operating conditions, in-situ XAFS, which allows for observation in the same environment while controlling the gas atmosphere and temperature of the sample, is effective. This document presents a case study where the valence states of Pt and Ru in PtRu/C catalysts were evaluated using in-situ XAFS in an environment controlled to the gas atmosphere and temperature actually used in fuel cells.

Carbon materials with nitrogen (N) atoms introduced as substitutes for platinum (Pt), the electrode catalyst in fuel cells, are attracting attention, and the catalytic activity is significantly related to the substitution positions of N within the carbon materials. XPS analysis allows for the evaluation of the N1s spectrum, where chemical shifts occur due to differences in bonding states and substitution positions of N, enabling the identification and quantitative separation of which C positions have been substituted by N.

Carbon nanotubes are lightweight nanomaterials with high strength and flexibility, and their excellent properties are expected to lead to applications in various fields. On the other hand, changes in physical properties associated with shape changes are also known, and evaluations of deformation and strain in response to external forces are required. This document introduces a case study of bending deformation simulations of single-walled carbon nanotubes using molecular dynamics calculations. By conducting simulations, it is possible to observe shape changes at the atomic level, which are difficult to evaluate from actual measurements, and to calculate strain energy.

Nuclear Magnetic Resonance Spectroscopy (NMR) is an analytical method that can obtain various information about molecular structure, intermolecular interactions, and molecular mobility, targeting various compounds including organic substances. This document presents examples of measurements conducted with a super low-temperature probe, which achieved higher sensitivity compared to a general-purpose room temperature probe.

In HAXPES, hard X-rays (Ga radiation) are used for excitation, which results in different positions of the Auger peaks compared to the Al and Mg radiation typically used in standard XPS measurements. Therefore, even in samples where the photoelectron peaks and Auger peaks overlap in Al and Mg measurements, this overlap can be avoided in Ga measurements, allowing for a detailed evaluation of the bonding states. This document presents the spectra of Kovar (an alloy of Fe, Ni, and Co) and GaN measured using Ga radiation (equipped with HAXPES) and Al and Mg radiation (equipped with XPS).

Carbon nanotubes (CNTs) are lightweight and possess excellent mechanical properties (high strength and high elasticity), making them suitable for various applications and environments. In particular, the deformation behavior of CNTs is related to flexibility and energy absorption characteristics, which are important in sensor and nano-device design. This document presents a case study that simulates the bending and recovery deformation of single-walled CNTs using molecular dynamics calculations. The simulation allows for the observation of structural changes at the atomic level due to environmental changes (pressure and temperature), enabling the analysis of deformation behavior based on the changes in strain energy associated with these structural changes.

We have launched a new service using XPS/HAXPES starting in June! For increasingly complex materials and fine structure samples, we can evaluate the composition and chemical bonding states from the surface to the interior of the material (up to ~30nm) at the same location and in a non-destructive manner. - Depending on the elements of interest and the analysis area and depth, we can select the appropriate X-ray source (Al Kα/Mg Kα/Ga Kα/Cr Kα) to achieve evaluation under suitable measurement conditions. - Non-exposure measurements to the atmosphere, Ar monomer/GCIB sputter etching, and heating pretreatment can be combined. - It is possible to evaluate the electronic states of semiconductor samples using UPS/LEIPS (ionization potential/electron affinity/band gap).