FisMat2017 - Submission - View

Abstract's title: Scanning Photoemission Imaging and Spectromicroscopy, a powerful tool for in situ and in operando characterization of Fuel Cell components
Submitting author: Matteo Amati
Affiliation: Elettra - Sincrotrone Trieste S.C.p.A. di interesse nazionale
Affiliation Address: Strada Statale 14 - km 163.5 in AREA Science Park, 34149 Basovizza, Trieste, ITALY
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Hikmet Sezen (Elettra - Sincrotrone Trieste S.C.p.A. di interesse nazionale, Strada Statale 14 - km 163.5 in AREA Science Park, 34149 Basovizza, Trieste, ITALY) , Mohamed Al-Hada (Elettra - Sincrotrone Trieste S.C.p.A. di interesse nazionale, Strada Statale 14 - km 163.5 in AREA Science Park, 34149 Basovizza, Trieste, ITALY),Benedetto Bozzini (Dipartimento di Ingegneria dell'Innovazione, Università del Salento, via Monteroni, 73100 Lecce, ITALY.), Luca Gregoratti (Elettra - Sincrotrone Trieste S.C.p.A. di interesse nazionale, Strada Statale 14 - km 163.5 in AREA Science Park, 34149 Basovizza, Trieste, ITALY)
Abstract

Fuel cells are electrochemical devices providing efficient and environmentally-friendly production of electricity directly converting the electrons exchanged in a redox reaction (such as a combustion) into electric current. One of the still unresolved issues that impedes their widespread applications is related to the limited durability of crucial components and mass transport events that deteriorate the performance.

The Scanning PhotoEmission Microscope (SPEM), hosted at the ESCAmicroscopy beamline at the Elettra synchrotron light source, uses a direct approach to characterize chemically surfaces and interfaces at the submicron scale i.e. the use of a small focused x-ray photon probe to illuminate the sample. The focusing of the x-ray beam is performed by using a Zone Plate (ZP) which is a Fresnel type lens. The SPEM can operate in two modes: imaging and spectroscopy. In the first mode the sample surface is mapped by synchronized–scanning  the sample with respect to the focused photon beam and collecting photoelectrons with a selected energy. The second mode is X-ray Photoelectron Spectroscopy (XPS) from a microspot. The X-ray beam can be downsized to a diameter of 120 nm which allows imaging resolution of less than 50 nm. The overall energy resolution is better than 200 meV [1].

Recent achievements in the chemical and electronic characterization of fuel cell components will be presented providing an overview of the capabilities of this powerful technique:

1)   In situcharacterization of novel non-noble metal catalysts for the Oxygen Reduction Reaction (ORR), i.e manganese/polypyrrole (Mn/PPy) nanocomposites. In this study, see reference [2],the pyrolysis process has been monitored in situ.

2)   Characterization of a Self-Driven Single Chamber SOFC in operando condition. In reference [3] we followed in-operando the evolution of chemical state and local potential at the electrodes of a Ni/YSZ/Mn self-driven cell resulting from the current flow.

The requirement for high-vacuum conditions in photoelectron spectroscopy and microscopy is a strong limiting factor for the characterization of fuel cell in realistic conditions. Only recently the development of electron energy analyzers with differentially pumped lens systems allowed to perform in situ XPS measurements up to few mBar (near ambient pressure). Results of innovative and cheap solutions developed at Elettra for photoemission microscopes, which can be potentially used to address the “pressure gap” in any XPS system, will be also presented and discussed [4].

[1] https://www.elettra.eu/elettra-beamlines/escamicroscopy.html

[2] B. Bozzini et al.  J. Mater. Chem. A, 2015, 3, 19155-19167

[3] B. Bozzini et al. Scientific Report  3, 2848, 2013

[4] Sezen H et al. ChemCatChem, Vol. 7 - 22, pp. 3665-3673 (2015)