Nuclear Magnetic Resonance Spectrometer (Responsible: Janez Plavec)

The Slovenian NMR Centre offers instruments and expertise for liquid- and solid-state NMR spectroscopy. Research at the NMR centre includes data acquisition and interpretation for those who apply NMR in basic and applied research projects. In situ NMR applications for surface electrochemistry allow the investigation, for instance, of the electrochemical oxidation of methanol and CO on the platinum cathode employing 13C and 195Pt NMR. NMR cells are designed to allow the complete integration of the fuel cell into the NMR probe, thus permitting operando studies.

Watch our videos about Liquid-State and Solid-State Nuclear Magnetic Resonance.

Electron Paramagnetic Resonance (Responsible: Mariana Stefan)

The EPR/ESR facility allows the investigation of physical phenomena in nanometric particles and the characterisation of bulk and nanostructured semiconductor and dielectric materials. Several examples of operando EPR on fuel cells are described in the literature (Niemöller, Jakes et al. 2016). Such a technique has also been employed to examine the degradation of polymer membrane in PEMFCs (Panchenko, Dilger et al. 2004) or studying AEMFCs (Wierzbicki, Douglin et al. 2020). Among its applications, it’s also included research on new catalysts.

High-Resolution Transmission Electron Microscopy, HRTEM (Responsible: Corneliu Ghica)

HRTEM is a multifunctional tool designed for the characterisation of advanced materials. This instrument allows for conventional transmission electron microscopy, high-resolution electron microscopy, electron tomography, in situ electron microscopy at high or cryogenic temperatures, energy dispersive X-ray spectroscopy, and elemental chemical mapping modes. HRTEM is actively employed for electrode investigations for fuel cell applications.

Watch our introduction video about HRTEM and EPR.

At the laboratory for ion-beam interactions (LIBI) are available proton beams ranging from 0,4 to 8 MeV, as well as most other heavy ions. The ion beam and the nuclear microanalysis activities based at LIBI are focused on three main areas:

• Element and isotope analysis with MeV ion beams
• Characterisation (i.e. crystal structure, morphology, density, charge transport) with MeV single ions
• Material modification by irradiation

Such analytical methods can address both elements (PIXE, RBS, ERDA) and isotopes (PIGE, NRA). Ion beam analysis methods can be applied to characterise hydrogen and other elements employed in fuel cell materials.

Applications of techniques like PIXE include the 2D mapping of dissolved and reprecipitated metallic components of electrocatalysts metals in the ionomeric membrane of PEMFCs. Furthermore, elastic recoil detection analysis (ERDA, RBS, and STIM) can be employed to determine the depth and density distribution of fuel cell components. Different types of measurements have been realised for the most diverse types of fuel cells, including Polymer Electrolyte Membrane FCs (PEMFC), Solid Oxide Fuel Cells (SOFC), and Molten Carbonate FCs (MCFC).

Available ion-based techniques are:

Nuclear Microprobe, NMICRO (Responsible: Milko Jakšić)

This technique is dedicated to ion-beam experiments with a high lateral spatial resolution down to 250 nm beam spot size. A flexible choice of ions and energies is allowed at this instrument. Three-dimensional hydrogen investigations can be realised in microprobe mode.

Particle-Inducted X-ray Emission and Rutherford Backscattering, PIXE/RBS (Responsible: Milko Jakšić)

The beamline is fed with a proton beam of typically 2 MeV with a circular spot size that can be adjusted in the range of 3-8 mm. A charger allows for the automatic loading of 16 samples. The instrument is equipped with two semiconductor PIXE detectors dedicated to lighter and heavier elements, respectively, and an RBS detector. PIXE detects ion-beam-induced X-rays, while RBS and ERDA analyse backscattered and recoiling ions. RBS and PIXE are complementary techniques, with RBS more sensitive to light elements. RBS is also employed for elemental depth profiling with near-surface sensitivity.

Time-of-Flight Elastic Recoil Detection Analysis, ToF-ERDA (Responsible: Milko Jakšić)

ERDA exploits elastic nuclear interaction between the ions of the beam and the atoms of the sample to perform quantitative elemental analysis for a wide range of elements, from hydrogen to rare-earth elements. The elemental analysis, especially for low-Z elements (such as Li, Be, B, C, N, O, F, Na, Mg, and Al), can also be performed by detecting particles or gamma-rays generated by nuclear reactions caused by ions penetrating the nucleus. This instrument enables the separation of all elements by energy and mass, allowing for depth profiling based on the energy distribution of heavy recoiled ions, with depth resolution down to 5 nm for C, N and O. Since forward recoil requires grazing incidence and Ultra-High Vacuum (UHV) conditions, only sample with low roughness (~10 nm) are eligible for analysis.

Neutron-based techniques are available at the Budapest Neutron Centre (BNC), where is located a 10 MW BWR tank-type reactor cooled and moderated with light water. The reactor is fuelled with 20% enriched uranium, yielding a thermal flux of 104 n cm-2. BNC expertise is focused on neutron diffraction and scattering, elemental analyses, and imaging. Neutron scattering methods are particularly relevant for FC studies since the kinetic energy of the neutrons allows the study of protons diffusion processes at the nanometre length scale. At the same time, the significant neutron penetration through materials allows operando observations in functional materials.

Available neutron-based techniques are:

Material test diffractometer, MTEST (Responsible: Alex Szakál, Tamás Veres)

MTEST is a general-purpose instrument routinely employed for a wide range of solid (powder), liquid and amorphous total diffraction samples in the Bragg and diffuse scattering modes. Neutron powder diffraction conveys information on the long-range structure of well-crystallised materials. It can be simultaneously operated with SANS, thus covering atomic to mesoscopic length scales in one experiment with the unique advantage that structural data can be obtained on the same sample under the same conditions. The sample environments allow for cryogenic (down to 77 K) and high temperature (up to 1273,15 K) tests. The MTEST staff is willing to test specialised FC sample environments developed by users.

Neutron Activation Analysis, NAA (Responsible: Katalin Gméling)

NAA is a general-purpose instrument for elemental analysis where the samples are irradiated in the reactor’s core. Therefore, the sample needs to be discarded after the investigation. This technique allows the quantitative composition analysis of chemical elements based on nuclear reactions, including trace impurities. This method is complementary to PGAA, and joint studies are possible. This instrument’s setup is adequate for ex situ compositional analyses of FC materials, particularly electrocatalysts. Ultra-precise quantification of the metal content of fuel cell cathodes and anodes is possible as the organic matrix does not produce any background.

Neutron imaging based on radiography and tomography, RAD (Responsible: Kis Zoltán):

RAD is a combined neutron/X-ray radiography/tomography instrument. The end station design enables static and dynamic imaging at a video rate. Specific sample stages are dedicated to small and large samples up to 250 kg. A classical approach for FC imaging by neutron radiography and tomography is the visualisation of water distribution in operating PEMFCs.

Neutron Reflectometry, GINA (Responsible: Dániel G. Merkel)

Neutron Reflectometry delivers a collimated and polarised beam onto the sample surface and measures the reflected intensity as a function of angle and neutron wavelength. The reflectivity profile reveals information about the structure of the surface, including thickness, density, roughness and dynamics of thin films in multi-layered samples. The current setup fits well the scales relevant for electrocatalytic studies. The brightness of the neutron source is not optimised for fast time-dependent studies, samples smaller than 1 cm2, and off-specular scattering.

Prompt Gamma Activation Analysis, PGAA (Responsible: Szentmiklósi László)

At PGAA, samples are irradiated with thermal neutrons. PGAA is one of the few techniques capable of directly quantifying hydrogen in situ. Therefore, it’s a perfect fit for FC studies. Instrument scientists already have expertise in measuring the composition of a Nafion membrane and the platinum content of commercial FC anode and cathode materials.

Watch the video about Prompt Gamma Activation Analysis.

Small-Angle Neutron Scattering, SANS (Responsible: Almásy László, Len Adèl)

Small-Angle Neutron Scattering detects the structure of materials at length scales in the range from nano- to micro-meters and is typically employed to estimate the size and shape of nano-sized materials. It enables various analyses, including defects in materials, multiphasic alloys, magnetic materials, polymers, and more. Past experiences include investigating polymers in fuel cells (Kulvelis, 2015; Kulvelis, 2016), the in situ and ex situ analysis of the behaviour of condensed water at different length scales, the operando study of water management in running fuel cells (Morin, 2016; Martinez, 2017), and more. The combination of neutron scattering and imaging allows for the joint investigation of water content at macro- and micro-scales in operating FCs (Iwate, 2019) and membrane swelling between ribs and channels (Martinez, 2019). The temperature control of samples allows for tests at high temperatures up to 363 K and cryogenic down to 10 K.

Watch our introduction video to Small-Angle Neutron Scattering.

Thermal Neutron Three–Axis Spectrometer and Neutron Holographic Instrument, TAST/HOLO (Responsible: Szakál Alex)

Inelastic Neutron Scattering measurement detect inelastically scattered neutrons at energies close to the Bragg peak, yielding information about the lattice dynamics. The detection can be performed both in neutron or gamma-ray modes. Fuel cell-related activities include the measurement of phonon and magnon dispersion in single crystals and analysing the phonon density in hydrogen-containing materials.

Time-Of-Flight Neutron Diffractometer, ToF-ND (Responsible: Káli György)

TOF-ND is a high-resolution time-of-flight powder diffractometer. The data acquisition system is optimised for time-dependent experiments. Current fuel cell/electrolysis studies include:

• Structure determination and refinement.
• Peak profile analysis.
• Phase and texture analysis of crystalline materials.
• Diffraction in liquids.

Deep X-ray Lithography, DXLR (Responsible: Benedetta Marmiroli)

DXLR is a manufacturing process in which a material exposed through an X-ray mask to synchrotron radiation in a liquid solvent changes its dissolution rate. In such a way, the mask pattern gets transferred onto the material. DXLR enables the fabrication of microstructures with a high spatial resolution (200 nm for a wall thickness of 100 um), high aspect ratios (up to 40), great structural heights (up to 3 mm), and parallel edges. Materials like plastics, metals, alloys, and ceramics can be manufactured in various shapes, filling the gap between the nano/micro scale and the macroscale. Microfabrication of FC devices and microfluidic fuel cells are topics that could be successfully investigated with this instrument. Such features can significantly impact fuel cell research and industrial applications.

Watch our introduction video about Deep X-ray Lithography.

Electron spectroscopy for chemical analysis, ESCA microscopy (Responsible: Luca Gregoratti)

ESCAmicroscopy beamline hosts a Scanning Photoelectron Microscope (SPEM). The high flux of the third-generation X-ray source feeding the line enables space-dependent quantitative and qualitative chemical characterisation of complex materials with micrometre spatial resolution. SPEM can operate in both spectroscopy and imaging mode. In spectroscopy mode, photoelectrons emitted by a micro spot defined down to 120 nm are analysed. In imaging mode, the sample is scanned across by a focused photon beam and only photoelectrons with selected kinetic energy are collected. Typical experiments include chemical and electrochemical reactions, mass-transport processes, morphology and electronic properties of materials. SPEM techniques are well established in the FC field and have proved to be one of the workhorses in determining the spatial inhomogeneities of fuel cell materials. This instrument allows chemical and electronic surface characterisations at submicron scales in ex situ, in situ, and operando modes at near ambient pressure conditions.

Field Emission Scanning Electron Microscope, FESEM (Responsible: Iva Matolínová, Vladimir Matolin)

Compared to a conventional Scanning Electron Microscope, FESEM produces a clearer and less electrostatically distorted image with a spatial resolution down to 1 nm. Besides the open access machine, a set of other supporting experimental setups are available to the users. The list includes FIB-SEM, electrochemical AFM, a fuel cell testing laboratory with ten test benches, two RDEs with bi-potentiostats, two magnetron sputtering systems for catalyst deposition, laser cutter, and an ultrasonic spray deposition system for CCM and CCGDL preparation. FESEM is designed for high-vacuum (HV) operations and is rigged with detectors allowing electron back-scattering spectroscopy (EBS) and energy dispersion X-ray spectroscopy (EDX) for chemical element mapping of surfaces with sub-micron resolution. The combination of SEM with EDX and FIB techniques is widely employed for the characterisation of various materials, including catalysts and membranes for hydrogen fuel cells and water electrolysers (Kúš, Ostroverkh et al. 2019; Yakovlev, Nováková et al. 2019; Hrbek, Kúš et al. 2020; Khalakhan, Supik et al. 2020; Nováková, Dubau et al. 2020).

High-Resolution Core-level Photoemission Spectroscopy, SuperESCA (Responsible: Luciano Lizzit)

SuperESCa beamline implements high-resolution core-level photoemission spectroscopy (HR-XPS). This method allows for in-depth investigations of the electronic and structural properties of different types of samples ranging from single crystals to thin films and nanostructured materials. SuperESCA combines high-resolution capabilities with a high flux of linearly polarised photons in the 90 – 1500 eV range, thus allowing to obtain high-resolution spectra, also in low-density systems, and to follow surface processes and reactions in real-time. This instrument is well suited for the ex situ characterisation of FC materials.

Inelastic UltraViolet Scattering, IUVS (Responsible: Barbara Rossi)

IUVS beamline is dedicated to the study of inelastic scattering with ultraviolet radiation in a time-space domain not accessible at present by other facilities. IUVS beamline delivers photons with incident energy between 5 and 11 eV. Incident photons inelastically diffused by the sample can be analysed by exploiting the two different and complementary experimental setups available at the beamline, UV Brillouin and UV Resonant Raman scattering. This setup allows acquiring information about the structure and dynamics of the constituent matter over different length scales through the analysis of its collective and molecular vibrations. SR-UVRR techniques are helpful for fuel cell, electrolysis and CO2 electro-reduction studies.

Laboratory Small-Angle X-ray Scattering, Lab-SAXS (Responsible: Manfred Kriechbaum):

The Lab-SAXS facility consists of a sealed tube X-ray generator with three opening ports and shutters with three SAXS cameras, one of which also allows grazing incidence SAXS (GISAXS) studies. Several sample holders for liquid and solid samples are available with thermostated sample holder stages. Both SAXS, SWAXS and continuous SWAXS are available at this instrument. SAXS is routinely employed for ex situ morphological characterisation of catalysts materials and membranes.

Materials Characterisation by X–ray Diffraction, MCX (Responsible: Jasper Rikkert Plasier)

MCX beamline is a general-purpose X-ray diffraction beamline with significant useful energy spanning from 6 to 20 keV. Many systems can be investigated, including organic and inorganic thin films, polymers, catalysts, and more. This instrument is ideally positioned to investigate model catalyst surfaces and is perfectly complementary to other CERIC-ERIC techniques and instruments such as XPS and SAXS. Bundling such techniques would provide a considerable added value to the FC community. Furthermore, standard powder diffraction experiments are also possible.

Material Sciences Beamline, MSB (Responsible: Nataliya Tsud, Tomas Skala)

Materials Science Beamline is a versatile beamline where classical UPS and XPS with high energy resolution and tunable excitation energy are available. This beamline also allows for resonant photoemission (RESPES) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopies in TEY mode. The sample can be rotated on two axes for angle-resolved photoemission studies. An electrochemical cell developed in cooperation with the NAP-XPS lab is available to the user community. At Materials Science Beamline, the research activity on (electro-)catalysis is active and lively.

Don’t miss our video about the Materials Science Beamline.

Nanospectroscopy, NASP (Responsible: Andrea Locatelli)

Nanospectroscopy beamline operates state-of-the-art spectroscopic photoemission and low energy electron microscope (SPELEEM). A small preparation chamber allows for simple treatments such as annealing and gas exposure. This technique allows for the characterisation of surface chemistry at various reaction stages in a sample fuel cell.

Near Ambient Pressure X–ray Photoelectron Spectroscopy (Responsible: Vladimir Matolin)

X-ray photoelectron spectroscopy (XPS) is a surface-sensitive quantitative spectroscopic technique. It allows the measurement of the elemental composition, empirical formula, chemical state, and electronic state of approximately the top 10 nm of a material. Differently from conventional XPS, which needs UHV conditions, Near-ambient Pressure XPS (NAP-XPS) can operate at a few tens of millibar, allowing to study the chemical interactions at the atomic level for vapour-solid interfaces. NAP-XPS also enables the investigations of small organic molecules’ electronic and structural properties. This facility closely cooperates with the Materials Science Beamline at the Elettra synchrotron. Various setups are available for CERIC users working on fuel cell research, including an electrochemical cell equipped with a Pt wire as a counter electrode and AgCl as a reference. This instrument is employed by various high-profile groups focusing on model (electro-) catalyst surfaces and materials for SOFCs. Such collaborations resulted in several high-impact publications (Faisal, Stumm et al. 2018; Bozzini, Previdi et al. 2019; Brummel, Lykhach et al. 2019).

Watch our video about the NAP-XPS technique.

Soft X–ray Transmission and Emission Microscope, TwinMic (Responsible: Alessandra Gianoncelli)

TwinMic is a soft X-ray microscope integrating the advantages of scanning and full-field imaging modes into a single instrument. The end station of TwinMic has the unique capability to operate both as a transmission X-ray microscope (TXM) and as a scanning TXM (STXM). TwinMic has been hosting users and collaborating on projects on energy research for over a decade. A considerable emphasis is put on battery research, fuel cells, electrocatalysis, corrosion and deposition. An example is given by the use of in situ X-ray imaging and spectro-microscopy to study metal corrosion products in PEMFCs (Bozzini, Gianoncelli et al. 2011). Other examples include in situ and operando studies examining the electrodeposition dynamics and morphology (Bozzini, Kourousias et al. 2017; Bozzini, Kourousias et al. 2017), as well as the speciation and morphology of reaction and corrosion products in FCs (Bozzini, Abyaneh et al. 2012; Bozzini, Gianoncelli et al. 2013).

Watch our video about TwinMic beamline.

Spectromicroscopy, SPEM (Responsible: Alexey Barinov)

This beamline houses a unique microscope designed to study the local band structure of materials. A low photon energy beam (below 100 eV) is focused into a sub-micrometre spot, and electrons arising from the photoemission process are collected and analysed in terms of their angular and energy distributions (ARPES). The sample can be measured in the temperature range of 40-460 K. This beamline works in Ultra High Vacuum (UHV) environment, thus limiting operando studies on fuel cells. However, flat-surfaced solid samples can be potentially studied. This setup allows for surface studies of model electrodes as a function of potential without the use of electrolytes.

Synchrotron Infrared Source for Spectroscopy and Imaging, SISSI (Responsible: Lisa Vaccari, Giovanni Birarda)

SISSI infrared beamline at Elettra extracts the IR and visible components of synchrotron emission to perform spectroscopy, microspectroscopy, and imaging. It is divided into the Chemical and Life Sciences branch line (SISSI-Bio) and the Materials Science branch line (SISSI-Mat). The materials Science branch line is equipped with a spectrometer for spectroscopy and spectromicroscopy measurement over a broad spectrum. This branch line is also equipped with cryostats and diamond anvil cells, allowing to explore the behaviour of matter under extreme conditions. The application of infrared radiation to fuel cell research would be of great interest for investigating the electrocatalytic activity of catalysts towards the relevant reactions taking place in fuel cell electrolysers.

Synchrotron Small-Angle X-ray Scattering, SAXS (Responsible: Heinz Amenitsch)

The SAXS beamline at the Elettra synchrotron allows for time-resolved studies on fast structural transitions in the sub-millisecond time region with a SAXS resolution of 1 to 140 nm in real space. GISAXS measurements for the structural investigation of thin films and the self-assembly process on surfaces are also available. The sample stage is located on an optical table allowing for the versatile optimisation of the measurement conditions and the implementation of users’ specialised equipment. On this beamline was developed an electrochemical cell suitable for studying the degradation of fuel cell catalysts (Bogar, Khalakhan, et al. 2020). The combination of (GI)SAXS and (GI)WAXS techniques is one of the workhorses in FC research and allows the study of electrocatalysts and other FC materials on the nanoscale. This instrument is very well placed for in situ and operando studies in this field. Joint complementary studies with electron and X-ray spectroscopy instruments within the CERIC-ERIC portfolio are possible.

Watch our video about the SAXS technique.

X–ray Absorption Fine Structure, XAFS (Responsible: Giuliana Aquilanti)

XAFS beamline is dedicated to X-ray Absorption Spectroscopy. This technique can provide information on the electronic structure and the local environment of the absorbing atom. Transmitted photons are measured using three ionisation chambers in series, simultaneously recording the XAS spectrum from both the sample and a reference. Several sample environments are available, including furnace, liquid-N2 cryostat, and cells for liquid samples. Different collection modes are as well available. The combination of such features meets the needs of various investigations. The beamline is very active in various topics, including catalysis and battery research. XAFS technique is suitable for state-of-the-art operando electrocatalysis and electrolysis studies on transition metal catalysts in liquid environments.

X–ray Photoelectron Diffraction, XPD (Responsible: Kateřina Veltruská)

XPD is a crystallographic technique combining information on morphology, electronic structure and chemical composition of the material. This technique provides a direct structure determination tool that best suits applications on periodic surfaces due to its sensitivity to the surface structural details on the local scale. XPD analysis can also be performed on systems lacking long-range periodicity. Suitable samples must be electrically conducting, ultra-high vacuum compatible, and with negligible roughness. For this purpose, in situ sample preparation is mandatory. XPD allows for the ex situ characterisation of FC materials.

X–ray Absorption Spectroscopy, LISA@ESRF (Responsible: Francesco d’Acapito)

Lisa is a bending magnet beamline installed on the ESRF-EBS (Extremely Brilliant Source) ring. LISA consists of three lead hutches: the Optical Hutch (OH) containing the main optical elements, the first Experimental Hutch (EH1) with the instrumentation for experiments with a non-focused beam, and a second Experimental Hutch (EH2) containing all the instrumentation for experiments with the focused beam. The beamline is equipped with instrumentation for X-ray Absorption Spectroscopy. Additional instrumentation is available for measurements in Total Electron Yield, ReflEXAFS and XEOL detection schemes. The instrumentation can be installed in either of the two experimental hutches to be used either with a large homogeneous beam (EH1) or with two focused beams (EH2). A pulsed diode laser synchronised with the storage ring Radio Frequency can be used for pump and probe experiments in stroboscopic mode. The Hard X-ray XAS technique is a critical characterisation method widely employed for studying the electronic structure of fuel cell materials, and the probe’s penetration power is a convenient advantage for in situ and operando experiments. This instrument has been involved for several years in research on electro-chemistry, photo-electro-chemistry, fuel cells, and water splitting (Wang, Lavacchi et al. 2015; Achilli, Minguzzi et al. 2016; Baran, Wojtyła et al. 2016; Miller, Lavacchi et al. 2016; Minguzzi, Naldoni et al. 2017; Berretti, Giaccherini et al. 2019).