66188 - Analysis of Surfaces and X-Ray Spectroscopies

Course Unit Page

SDGs

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.

Quality education Affordable and clean energy

Academic Year 2021/2022

Learning outcomes

The course provides educational experiences which challenge students to: be aware of the characteristics of X-ray methods of analysis (X-ray absorption and emission spectroscopy, microscopy) as a strong structural tool: advantages, disadvantages, and applicability in the applied chemistry; be aware of the electronic information contained in the XAFS spectrum and its applicability; perform a preliminary XAS data reduction; be aware of the most recent core-level spectroscopy analytical techniques for solid and solutions; to design spectroscopic in-situ experiments.

Course contents

Introduction to surface analysis and electron microscopy.

X-rays: origin and generation. X-ray absorption coefficient and mass absorption coefficient. Calculations and examples on mass absorption coefficient. Decay of the core-hole: x-ray Fluorescence and Auger effect. Analytical application of Absorption.

X-ray absorption spectroscopy and the acronyms XANES, EXAFS, SEXAFS, NEXAFS, … Experimental methods: absorption and fluorescence. Synchrotron radiation. XAS Spectroelectrochemistry and cells for in-situ measurements. Applications: Examples in the field of solution chemistry, surfaces, catalysis, batteries, inorganic and biological materials.

X-ray fluorescence. instruments and applications. The matrix effect in x-ray fluorescence.

Main surface electron-probe techniques: ESCA and Auger. Instruments and characteristics, resolution and sampling depth. Chemical shifts.

Data Analysis. XANES calculations ad EXAFS fittings. Primary data reduction: extraction of the (k) and Fourier Transformation. Data analysis using fitting approach. Chemometry for spectroscopy. Use of Multivariate Curve Resolution - Alternating Least Square (MCR-ALS) algorithm for the analysis of operando data collection.

Readings/Bibliography

Willard, Merrit, Dean, Settle, "Instrumental methods of analysis" WADSWORTH PUBLISHING COMPANY

G. Bunker, “Introduction to XAFS” Cambridge University Press, 2010.

Marco Giorgetti (2013). "A Review on the Structural Studies of Batteries and Host Materials by X-Ray Absorption Spectroscopy". Free download at: https://www.hindawi.com/journals/isrn/2013/938625/cta/

Marco Giorgetti and Lorenzo Stievano (2017). "X-Ray Absorption Spectroscopy Study of Battery Materials". Free download at: https://www.intechopen.com/chapter/pdf-download/53744

Dino Tonti, Mara Olivares-Marín, Andrea Sorrentino and Eva Pereiro (2017). "Studies of Lithium-Oxygen Battery Electrodes by Energy- Dependent Full-Field Transmission Soft X-Ray Microscopy". Free download at: https://www.intechopen.com/chapter/pdf-download/53739

Other specific material will be given by the teacher.

Teaching methods

The course describes the potentiality of both X-Ray Absorption and X-Ray Emission as an electronic and structural tools for the study of the condensed, crystalline, solution and amorphous phases. Front lectures and exercitation will be the offered with several examples concerning basic data analysis and interpretation of spectra.

Assessment methods

The final examination will determine the level reached by the student in the objectives set out in the "Learning outcomes”. The assessment of the learning consists in an oral presentation on a selected topics learned during the course with a maximum of 15 slides (according to lectures and/or materials from scientific papers).

During the oral exam, the student explains the science behind the topic/article. Then a discussion follows on the presented concepts and the theme of the article inspires to discuss the basic concepts common to all the topics covered in class.

The final assessment takes into account both the exposure (15 points) and the ability to discuss the general concepts (18 points). The honor (cum laude) is reached with 33 points.

The duration of the oral examination is about 30-40 minutes.

Teaching tools

Slides relating to lectures and other material useful for exam preparation is made available to the student electronically. To get the teaching material the student must be register to the course through the site virtuale.unibo.it.

Office hours

See the website of Marco Giorgetti