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The performance of new materials and devices often depends on processes taking place at the interface between an active solid element and the environment (such as air, water or other fluids). Understanding and controlling such interfacial processes require surface-specific spectroscopic information acquired under real-world operating conditions, which can be challenging because standard approaches such as X-ray photoelectron spectroscopy generally require high-vacuum conditions. The state-of-the-art approach to this problem relies on unique and expensive apparatus including electron analysers coupled with sophisticated differentially pumped lenses. Here, we develop a simple environmental cell with graphene oxide windows that are transparent to low-energy electrons (down to 400 eV), and demonstrate the feasibility of X-ray photoelectron spectroscopy measurements on model samples such as gold nanoparticles and aqueous salt solution placed on the back side of a window. These proof-of-principle results show the potential of using graphene oxide, graphene and other emerging ultrathin membrane windows for the fabrication of low-cost, single-use environmental cells compatible with commercial X-ray and Auger microprobes as well as scanning or transmission electron microscopes. Thin graphene oxide windows can be used in X-ray photoelectron spectroscopy of environmental cells by virtue of their transparency to low-energy electrons.

The modifications in the electronic properties induced by the thickness and size of an individual flake of transition-metal halides on different substrates (silicon oxide or In-doped tin oxide) are of particular technological interest, even more in the case of chromium trihalides (CrX3, X = Cl, Br, and I), whose longer lifetime under ambient conditions is particularly intriguing. By using synchrotron-based scanning photoelectron microscopy with a resolution of 0.1 μm and Kelvin probe force microscopy, we evaluated the surface modification reaction and the surface potential. Our results established the correlations of the two latter properties with the thickness of flakes, observing a natural tendency to preserve their characteristic when the flakes have significantly less thickness. This is in contrast to thicker flakes, which show alteration patterns similar to those observed in bulk-cleaved samples (Kazim, S.; Mastrippolito, D.; Moras, P.; Jugovac, M.; Klimczuk, T.; Ali, M.; Ottaviano, L.; Gunnella, R. Phys. Chem. Chem. Phys.2023, 25, 3806–3814. https://doi.org/10.1039%2FD2CP04586A%29. This preliminary study investigates interfaces made by dry transfer of CrCl3 flakes in an atmospheric environment. Cl vacancies and the formation of O/CrCl3 are induced, serving as dissociation centers that facilitate the migration of Cl vacancies between the top and bottom surfaces. By manipulating 2D atomic layers via surface oxidation or the introduction of surface vacancies, a novel and versatile approach is unveiled for the development of low-dimensional multifunctional nanodevices.

Nanostructured materials play a key role in modern technologies adding new functionalities and improving the performance of current and future applications. Due to their nature resulting in diffused heterogeneous structures (chemical and electronic composition typically organized in phases or building blocks) characterizing these materials needs state of the art technologies which combine nanometer spatial resolution, environmental reliability, and operando capabilities. Scanning photoelectron spectromicroscopy (SPEM) is one of the characterization tools that combine high spectral resolution X-ray photoelectron spectroscopy with submicron spatial resolution. In particular, the SPEM equipment hosted at the ESCA microscopy beamline at Elettra is capable of in situ and operando analysis regardless of sample morphology. The review presents three different case studies illustrating the capabilities of SPEM in the investigation of catalytic materials in different conditions and processes.

In this study the adsorption and photodegradation capabilities of modified multi-walled carbon nanotubes (MWCNTs), using tartrazine as a model pollutant, is demonstrated. MWCNT-COOH/Fe3O4 and MWCNT-COOH/Fe3O4/NiO nanocomposites were prepared by precipitation of metal oxides in the presence of MWCNTs. Their properties were examined by X-ray diffraction in powder (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, synchrotron-based Scanning PhotoElectron Microscopy (SPEM), and Brunauer-Emmett-Teller (BET) analysis. It was found that the optimal adsorption conditions were pH 4 for MWCNT-COOH/Fe3O4 and pH 3 for MWCNT-COOH/Fe3O4/NiO, temperature 25 °C, adsorbent dose 1 g L−1, initial concentration of tartrazine 5 mg L−1 for MWCNT-COOH/Fe3O4 and 10 mg L−1 for MWCNT-COOH/Fe3O4/NiO and contact time 5 min for MWCNT-COOH/Fe3O4/NiO and 15 min for MWCNT-COOH/Fe3O4. Moreover, the predominant degradation process was elucidated simultaneously, with and without simulated sunlight irradiation, using thermal lens spectrometry (TLS) and UV–Vis absorption spectrophotometry. The results indicated the prevalence of the photodegradation mechanism over adsorption from the beginning of the degradation process.

A Scanning Photoelectron Microscopy (SPEM) experiment has been applied to ZnO:N films deposited by Atomic Layer Deposition (ALD) under O-rich conditions and post-growth annealed in oxygen at 800 °C. State-of-the-Art spatial resolution (130 nm) allows for probing the electronic structure of single column of growth. The samples were cleaved under ultra-high vacuum (UHV) conditions to open atomically clean cross-sectional areas for SPEM experiment. It has been shown that different columns reveal considerably different shape of the valence band (VB) photoemission spectra and that some of them are shifted towards the bandgap. The shift of the VB maximum, which is associated with hybridization with acceptor states, was found to be correlated with carbon content measured as a relative intensity of the C1s and Zn3d core levels. Generalized Gradient Approximation (GGA) supplemented by +U correction was applied to both Zn3d and O2p orbitals for calculation of the VZn migration properties by the Nudged Elastic Band (NEB) method. The results suggest that interstitial -CHx groups facilitate the formation of acceptor complexes due to additional lattice perturbation.

Solid-state batteries (SSB), characterized by solid-state electrolytes—in particular inorganic ones (ISSE)—are an ideal option for the safe implementation of metallic Li anodes. Even though SSBs with ISSEs have been extensively investigated over the last two decades, they still exhibit a series of technological drawbacks. In fact, mechano-chemical issues, mainly the stability of the electrolyte/anode interface, hinder their widespread application. The present investigation focusses on a thin-film LMO (Lithium-Manganese-Oxide)/LAGP (LiAlGe Phosphate)/Copper, anodeless Lithium-metal battery and explores the morphochemical evolution of the electrode/electrolyte interfaces with synchrotron-based Scanning Photoelectron Microscopy (SPEM) of intact pristine and cycled cells. Chemical images were acquired with submicrometer resolution, to highlight the coupled geometrical and chemical-state changes caused by electrochemical ageing. Geometrical changes of the electrolyte/cathode interface were induced by periodic volume changes, causing de-cohesion of the solid-solid contact, but no chemical-state changes accompany the cathodic damaging mode. Instead, shape changes of the electrolyte/anode region pinpoint the correlation between mechanical damaging with the decomposition of the LAGP ISSE, due to the reduction of Ge, triggered by the contact with elemental Li. The micro-spectroscopic approach adopted in this study enabled the assessment of the highly localized nature of the cathodic and anodic degradation modes in SSB devices and to single out the chemical and mechanical contributions.

Flexible carbon nanotube (CNT) chemoresistors offer a scalable, low‐cost platform for wearable gas detection. However, a clear understanding of their sensing mechanism remains essential to optimize sensitivity, selectivity, and overall reliability. In this work, we complement electrical response measurements in both dry air and ultra‐high vacuum (UHV) with synchrotron‐based in situ X‐ray photoelectron spectroscopy (XPS) to directly probe ammonia (NH3)–CNT interactions. In both environments, the response can be described by Langmuir‐type adsorption–desorption kinetics. In dry air (3–50 ppm), the devices exhibit a reproducible increase in resistance with a sensitivity of ∼0.4% ppm−1. Under UHV, a nominal NH3 concentration of ∼8 ppm produces a smaller relative response of ∼0.5%, comparable to that obtained at 3 ppm in dry air. In situ micro‐focused XPS reveals reversible (≈1 eV) shifts in the C 1s core‐level binding energy during NH3 exposure, confirming that NH3 acts as an electron donor. This spectroscopic evidence correlates quantitatively with the chemoresistive response, establishing intra‐CNT charge transfer as the dominant transduction mechanism. These findings underscore the effectiveness of coupling XPS with electrical analysis to unravel gas‐sensor transduction in nanomaterials and pave the way for the rational design of high‐performance CNT‐based sensors. Flexible carbon nanotube chemoresistors detect NH3 through charge‐transfer interactions directly revealed by in situ synchrotron X‐ray photoelectron spectroscopy. Binding‐energy shifts of ≈1 eV correlate with resistance changes, demonstrating that intra‐CNT charge transfer between NH3 and CNTs is the dominant sensing mechanism. This combined spectroscopic–electrical approach advances the rational design of reliable CNT‐based gas sensors.

The challenges in development of solid oxide fuel cells (SOFCs) are reducing their dimensions and increasing their efficiency and durability, which requires physicochemical characterization at micro-scales of the device components during operation conditions. Recently, the unique potential of scanning photoelectron microscopy (SPEM) has been demonstrated by in-situ studies of externally-driven SOFCs, which mimic real devices. Here we overcome the gap between model and real systems using a single-chamber Ni|YSZ|Mn SOFC, supporting a range of self-driven electrochemical reactions in variable gas environments and temperatures. The reported SPEM results, obtained during spontaneous electrochemical processes occurring in reactive gas ambient, demonstrate the chemical evolution of electrodic material, in particular the lateral distribution of the oxidation state and the induced local potential, clearly marking out the electrochemically most active micro-regions of the Ni anode.

The relatively small size of thin （one or few layers） graphene flakes makes it extremely difficult to study the behavior of suspended graphene by characterization techniques other than the electron microscopies. Herein, we exploited the capability of spatially resolved photoemission in combination with high resolution transmission electron microscopy to investigate the interaction of thermally evaporated Pt atoms on suspended and supported graphene. Spectroscopic and microscopic analyses reveal that the nucleation of nanometer- sized Pt particles in these two regions exhibit different trends. While only small nanometer-sized islands are present on the supported graphene, relatively larger clusters of islands were also found on the suspended flakes. The X-ray photoemission C ls core levels acquired after the Pt deposition show an increase in the number of vacancies in the graphene sheets.

Suspended graphene is exposed to different fluorine-containing species producedby a plasma source fed with CF4 precursor gas. We investigate the fluorinationprocess by selecting two different kinetic energies for the ions striking the graphenesurface. The chemical-bonding environment is discussed, and the control of thegraphene-fluorination homogeneity is investigated at the individual graphenesheets. The modifications of the electronic and structural properties are examinedby scanning photoelectron microscopy, micro-Raman analysis, and scanningelectron microscopy. The results are compared with those obtained for supportedgraphene on copper. Suspended graphene provides a quasi-ideal model forinvestigating the intrinsic properties of irradiated carbon nano-systems whileavoiding damage due to backscattered atoms and recoil due to a supportingsubstrate.