Semarang, September 9, 2025 — The Department of Physics, Faculty of Science and Mathematics (FSM), Diponegoro University successfully hosted an International Guest Lecture featuring distinguished speaker Prof. Takahsi Yamamoto from Tokushima University, Japan.
The event, held online, was attended by students and faculty members from the Physics Study Program of FSM Undip. Prof. Yamamoto delivered a lecture on the topic “Analysis of Solid Catalysts and Environmental Samples using a Lab-Based XAFS Spectrometer.”
In his lecture, Prof. Yamamoto provided an in-depth explanation of X-ray Absorption Spectroscopy (XAS)—a highly sensitive and element-selective technique for analyzing atomic structures. XAS encompasses two main approaches: XANES (X-ray Absorption Near Edge Structure) and EXAFS (Extended X-ray Absorption Fine Structure).
Through XANES, researchers can obtain detailed information about an element’s oxidation state and local coordination geometry, while EXAFS enables the quantitative analysis of interatomic distances, types of neighboring atoms, and coordination numbers.
One of the major advantages of XAS, as highlighted by Prof. Yamamoto, is its ability to analyze materials without requiring high crystallinity, making it ideal for the characterization of amorphous materials, nanomaterials, and biological systems. The technique operates by measuring the amount of X-ray absorbed by an element as the X-ray energy is increased beyond the ionization threshold of its inner-shell electrons.
This interaction produces a characteristic absorption spectrum, where the XANES region reveals information about valence and local symmetry, while the EXAFS region discloses interatomic distances and local coordination structures.
During the presentation, Prof. Yamamoto also emphasized the wide-ranging applications of XAS in cutting-edge research fields, including:
Heterogeneous catalysis, for identifying active sites on catalyst surfaces,
Energy storage and conversion, such as in batteries and fuel cells,
Environmental science, including heavy metal speciation analysis, and
Biochemistry, to study metal structures in enzymes and proteins.
The capability of XAS to perform in-situ and operando analysis makes it an indispensable tool for investigating functional materials and complex modern systems. It can also be applied to study surface atomic structures and electronic changes in metal and oxide nanoparticles, which play a crucial role in the development of nanomaterial technologies.
In addition to explaining the fundamental principles and applications of XAS, Prof. Yamamoto introduced the concept and advantages of the lab-based XAFS spectrometer, which allows researchers to perform XAS measurements without relying on synchrotron facilities.
This innovation provides new opportunities for universities and laboratories worldwide to conduct advanced material research more efficiently and affordably.
The lecture received enthusiastic responses from FSM Undip’s students and faculty. Participants actively engaged in discussions and asked questions regarding the implementation of XAS in catalyst and energy material research.
“This lecture provides new insights for students on atomic structure analysis techniques that are essential for modern materials research,” said Prof. Eko Hidayanto, a lecturer in spectroscopy at FSM Undip.
“We hope that academic collaboration between Undip and Tokushima University will continue to grow, especially in the field of functional materials research.”
Through this event, the Department of Physics, FSM Undip reaffirms its commitment to organizing international academic activities that enrich student knowledge, strengthen global research collaboration, and enhance the quality of education and research in material physics and modern spectroscopy.