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Fe-Nx-C electrocatalysts for the oxygen reduction reaction are typically fabricated via pyrolysis. However, the pyrolysis process is poorly understood. Therefore, a systematic investigation was initiated to elucidate the effects of the pyrolysis conditions (atmosphere and temperature) on the evolution of active sites starting from iron phthalocyanine supported over carbon black. The atomic level dispersion of Fe-Nx is sustained up to 600 °C and afterward, the growth of iron oxide nanoparticles is observed. Interestingly, the different X-ray absorption spectroscopy fingerprints acquired during in-situ and ex-situ experiments indicated the bonding of oxygen as a fifth ligand on the Fe sites when exposed to the open air. The ORR activities were analyzed in acidic and alkaline media. The best electrocatalytic activity was observed for the electrocatalysts pyrolyzed at 600 °C. Above this temperature, a reduction in the activity was observed. Surface-to-reactivity analysis was carried out identifying the relationship between surface chemistry/morphology and electrocatalytic activity.

In this manuscript, a comprehensive study is presented on Fe-based electrocatalysts with mono, bi, and tri-metallic compositions, emphasizing the influence of processing-structure correlations on the electrocatalytic activity for the oxygen reduction reaction (ORR) in the alkaline medium. These electrocatalysts were synthesized through the mixing of transition metal phthalocyanines (TM-Pc) with conductive carbon support, followed by controlled thermal treatment at specific temperatures (600 °C and 900 °C). An extensive analysis was conducted, employing various techniques, including X-ray Absorption Spectroscopy (XAS), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD), providing valuable insights into the structural characteristics of the synthesized nanoparticles. Importantly, an increase in the Fe-Pc weight percentage from 10% to 30% enhanced the ORR activity, although not proportionally. Furthermore, a comparative analysis between mono, bi, and tri-metallic samples subjected to different functionalization temperatures highlighted the superior electrocatalytic activity of electrocatalysts functionalized at 600 °C, particularly Fe 600 and Fe-Ni-Cu 600. These electrocatalysts featured Eon values of 0.96 V vs. RHE and E1/2 values of 0.9 V vs. RHE, with the added benefit of reduced anionic peroxide production. The potential of these Fe-based electrocatalysts to enhance ORR efficiency is underscored by this research, contributing to the development of more effective and sustainable electrocatalysts for energy conversion technologies.

In the cultural heritage field, non-invasive analyses are becoming more important as they avoid any sampling, allowing in situ measurements to be performed. XRF is one of the most common among those techniques, as it allows elemental speciation of the sample with a range that goes from F to U. However, the main limitation of this technique on cultural heritage objects is due to their intrinsic inhomogeneity, both lateral and in-depth. If MA-XRF has overcome the lateral inhomogeneity through the collection of multiple XRF spectra in different positions, it is more difficult to find an optimal way to perform in-depth analyses. Now, only confocal micro XRF allows for precise 3D analyses, as other techniques are limited to certain kinds of samples. In recent years, however, angle-resolved XRF has given promising results in the analysis of layered samples. In this study, we will review the information about this new analytical technique and its advantages and disadvantages in studying cultural heritage objects following our recent studies.

Bronze is an alloy composed primarily of copper and tin and since its discovery is widespread in the whole world. This alloy can thus be found in many archaeological sites and its study can give information about the technology of production, the trading routes, or the warfare within a region. However, bronze artefacts can undergo severe alteration processes, and the formation of corrosion layers of different copper minerals can prevent the readability of the artefact or even destroy it, as in the case of the ‘bronze disease’. Their preservation is crucial for maintaining a connection to our cultural heritage. In this paper, we present the study of some corroded bronze artefacts found in different burying conditions. They have been analysed through a scanner system that combines two non-invasive techniques, macro XRF (MA-XRF) and visible, near infrared, short wave infrared (VIS-NIR-SWIR) reflectance, to unravel information about the metal and the patina composition, thickness, and distribution. As the corrosion of bronze depends on the burying conditions and the alloy composition, these data are of the utmost importance to understanding the alteration processes occurring in the archaeological site and to ensure the artefacts’ optimal preservation.

In February 2016, 47 ingots were found in the seabed of Contrada Bulala (Gela, CL, Italy) near the site where in 2014 40 ingots had previously been recovered. The ingots composition was determined to be a Cu - Zn alloy [1], dated by the archaeologist to the VI century B.C. This specific alloy was then identified as orichalcum. From an archaeological point of view, the interest was to define the relation between the two discoveries and the origin of primary sources of metals. In previous studies, fundamental information was achieved by applying chemometric treatment of the analytical results obtained on microsamples from ingots from first and second discovery [2,3]. Starting from this database and from availability of microsamples taken from the ingots, we discuss the feasibility to obtain elemental and spectroscopic information from the investigated area by using a non-invasive approach. A recently commercialized portable instrumentation dedicated to synchronous and co-registered XRF and Vis-SWIR hyperspectral measurement, with non-destructive and contactless approach to the samples, has been used to analyze three microsamples taken from three different ingots of the 2016 group. With the purpose to build a non-invasive in situ protocol, the XRF obtained results are compared with the literature data [1-3] and they match. Moreover, the hyperspectral measurements are cross-checked with diffuse reflectance spectra acquired with a spectrophotometer in the UV-vis region, where the response related to the Cu transition in the alloy can be detected. The spectra of the three samples look very similar, with a broad minimum from about 250 nm up to 450 nm and a shoulder at about 600 nm; both these features, typical of brass, are known to vary as a function of Cu and Zn concentrations [4], which are indeed very close for the three samples (Cu ≥70% and Zn ≤20%). In addition, the spectra of the samples with the same Pb-isotope ratio are nearly identical.

In this work, platinum group metal-free (PGM-free) electrocatalysts were synthesized, characterized, and tested for hydrogen evolution reaction (HER). These materials were mono-, bi- and trimetallic Ni-based electrocatalysts with the addition of a second or a third transition metal (TM), such as iron and cobalt. TM–phthalocyanine (TMPc) was used as a metal precursor, mixed with a conductive carbon backbone and subjected to pyrolysis under controlled temperature and atmosphere conditions. Two temperatures of pyrolysis (600 °C and 900 °C) were used. The effect of TM loading in the precursors, different pyrolysis temperatures on the surface chemistry and morphology, and electrocatalytic activity towards HER were evaluated. The increase of NiPc in the initial mixture is beneficial to improving the electrocatalytic activity. The addition of a second and a third metal reflects positively on the HER performance. Interestingly, the pyrolysis temperature influences both the formation and growth of the nanoparticles, and this information is supported by high-resolution transmission electron microscopy (HR-TEM) and light synchrotron X-ray absorption spectroscopy (XAS) measurements.

With Angle Resolved XRF (AR-XRF) the sample is investigated at different angles of detection and irradiation. The geometry of analysis indeed affects the intensity of the characteristic elemental fluorescence signal of the sample, which depends on the element distribution inside the sample. This technique has already proved to be very useful in analyzing metallic bilayer samples. In this paper, we applied AR-XRF to study a real case in the field of Cultural Heritage, with the analysis of a glazed ceramic coming from Puebla, Mexico. The analysis of the decorations, which present different thicknesses and compositions, has shown the limits of the technique, especially in the case of thick and diffused layers, and the importance of a priori knowledge to retrieve structural information in the case of a complex system with a great number of variables.

L’analisi scientifica è da un po’ di tempo entrata nel mondo dei beni culturali, non sono più solo gli archeologi e gli storici dell’arte a occuparsi dello studio dei reperti archeologici e storici, ma anche gli scienziati sono entrati a gamba tesa portando le loro conoscenze al servizio di questa vasta gamma di materiali. Lo studio di reperti botanici e zoologici, le competenze chimiche e mineralogiche, lo studio di fenomeni fisici, ha permesso di porre e rispondere a nuove domande, colmando così lacune sulla storia dell’umanità. Reti commerciali, migrazioni, tecniche produttive, molte sono state le scoperte avvenute grazie anche all’intervento scientifico, oltre a fornire strumenti utili al restauro e alla conservazione dei reperti. Nei miei tre anni di dottorato mi sono occupato dell’applicazione dell’analisi in Fluorescenza a Raggi X (XRF) per analizzare campioni metallici e ceramici. Questa tecnica ha il vantaggio di poter essere applicata in maniera non invasiva e non distruttiva su un reperto per ottenere informazioni sulla sua composizione elementare. In particolare, il nostro obiettivo è quello di ottenere informazioni sui diversi strati che compongono un campione. Spesso, infatti, i manufatti presentano una struttura stratificata causata dal passaggio degli anni o dalla natura stessa dell’oggetto, che presenza una serie di decorazioni superficiali. L’impiego di tecniche non invasive permetterebbe quindi di ottenere informazioni più dettagliate anche su campioni al momento inaccessibili, in quanto troppo fragili o troppo preziosi. Lo studio si è quindi avvalso di tecniche a scansione angolare, per cui il segnale di fluorescenza caratteristica dipende sia dalla posizione dell’analita all’interno del campione, sia dalla struttura e composizione dello stesso, sia dalla geometria di analisi. Per valutare l’applicabilità delle tecniche sono stati analizzati tre casi diversi: campioni metallici preparati ad hoc in laboratorio, un campione ceramico, e un c, In the last decades scientific analysis has been deeply employed in the world of cultural heritage, thus, archaeologists and art historians are no more the sole front line workers of this field. Scientists, and science, have joined the team, giving new inputs and tools for the study of historical and archaeological samples, allowing to explore new paths and receive new answers, collecting information otherwise inaccessible on human history and culture. New discoveries have been made on the trade networks, migrations and on the technologies employed; besides, science also gave precious inputs on conservation and restoring procedures, allowing to better preserve fragile and sensitive artifacts. In my three years as a PhD student, I worked on the application of X-Ray Fluorescence (XRF) analysis to analyze ceramic and metal samples. XRF is a non-invasive technique that retrieves the elemental composition of a sample. In particular the aim of my PhD project is to obtain information on the layered structure of an unknown sample, distinguishing and characterizing the different layers. Indeed, artifacts usually concerning the field of Cultural Heritage present a layered structure; sometimes it is due to the presence of alteration layers, other times, instead, the objects are made of different layers from the principle, for example in the case of a glazed ceramic or of a painting. The possibility to get this information in a non-invasive way will give the possibility to analyze objects that are nowadays unattainable, because they cannot be sampled. My project has, thus, focused on the analysis of three kinds of samples employing angular dependent techniques (Angle Resolved-XRF, Grazing Emission-XRF}, Grazing Incidence-XRF}); indeed, the fluorescence signal of an analyte depends on its position inside the sample, on the sample composition and on the geometry of analysis. The chosen specimens allowed to verify the feasibility of this analytical method in an increasing complexi

Angle resolved XRF (AR-XRF) is an analytical technique in which the sample is analyzed at different angles of detection or irradiation. The change in the geometry affects the intensity of the elemental characteristic emission from the sample, which depends on the in-depth distribution of analyte. In this paper, for the first time, we apply AR-XRF to gilding samples that mime real cultural heritage ones. The samples analysed, also investigated with scanning electron microscopy, present small lateral inhomogeneities and a rough surface. Moreover, we illustrate how to analyze AR-XRF data, from the collection of XRF spectra to the creation of AR-XRF profiles and the fitting of data using Sherman's equation. Using AR-XRF combined with the fundamental parameters method we calculate the massive thickness of laboratory made layered samples.

Pulsed thermography was exploited to identify the presence of glass defects in order to get an indication of the conservation status of archaeological glass. Indeed, the process of degradation in artifacts subjected to centuries of burial can be of great relevance. More specifically, we evaluated the potential of pulsed thermography to map the presence of flakes in archaeological glass. This was achieved by comparing different heating setups and signal-processing algorithms. Tests were carried out previously on glass mockups with surface defects and then on archaeological artifacts.

The project FUXYA2020 was intended to design and prototype a low-cost basic energy dispersive X-ray fluorescence spectrometer for all those cases where there is not enough financial support to buy a commercial device. Indeed, home-made instruments are ideal when funds are low but constant over the years, as this approach allows the costs to be spread over a longer period of time. The FUXYA2020 was intended mostly for cultural heritage (CH) applications: we optimized the geometry to meet the requirements for both low Z matrix objects, such as glasses and ceramics, and medium-high Z materials, such as metals; besides, we designed a positioning system through Arduino components to obtain good results and repeatability for samples with a complex geometry. The FUXYA2020’s performance was tested both for qualitative and quantitative analyses, the former on pigment layers, and the latter on gold-based certified alloys, exploiting Axil-QXAS software for data elaboration. The classification of ancient ceramics based on multivariate analysis obtained through R environment was also carried out. The qualitative data on pigments have also been compared with the same data obtained by a commercial XRF spectrometer, demonstrating how our very simple and inexpensive prototype can be of great help for a rapid and reliable characterization of cultural heritage materials whenever commercial devices are unaffordable.

The field of Cultural Heritage (CH) comprises many rare, valuable, and fragile samples and for this very reason non-invasive and non-destructive techniques are the most preferred to their analysis. Among these techniques, XRF allows to perform a fast elemental characterization of the artifacts, detecting a high range of elements (from Al to U in air). XRF allows also to perform quantitative analysis, which is more feasible and reliable if the samples are of infinite thickness for the considered radiation, homogenous and flat. Unfortunately, many samples related to the field of CH are inhomogeneous, and they often present a layered structured. Indeed, they may have been created as a series of layer (like painting, surface-decorated ceramics, or gilded metals) or their surface may have been alteredby crust or patinas formation over the surface. In these cases, it can be useful to characterize the composition and the thickness of each layer, as to support inferences on the materials and technology employed to produce the layers, or on the alteration process behind the presence of the crusts. The characterization of the layered structure can be performed by means of data analysis, like the calculation Ka/Kb La/Lb ratio, or the use of Monte Carlo simulations; by employing lenses to select the volume of analysis (Confocal XRF); or by developing a proper experimental set-up: for nanolayers it is possible to use grazing emission or grazing incident XRF, while for thicker layer angle resolved XRF (AR-XRF) can be performed. AR-XRF is an experimental set-up in which the sample is analyzed at different angles (of irradiation or detection or both); the intensity of the elements’ characteristic lines changes accordingly the pathlength crossed by the source radiation and by the fluorescence radiation, which is changed during the experiment. The presence of different elements in different layers can be inferred by the intensity profiles obtained from the angular scanning. In this w

Among the possible variants of X-Ray Fluorescence (XRF), applications exploiting scanning Macro-XRF (MA-XRF) are lately widespread as they allow the visualization of the element distribution maintaining a non-destructive approach. The surface is scanned with a focused or collimated X-ray beam of millimeters or less: analyzing the emitted fluorescence radiation, also elements present below the surface contribute to the elemental distribution image obtained, due to the penetrative nature of X-rays. The importance of this method in the investigation of historical paintings is so obvious-as the elemental distribution obtained can reveal hidden sub-surface layers, including changes made by the artist, or restorations, without any damage to the object-that recently specific international conferences have been held. The present paper summarizes the advantages and limitations of using MA-XRF considering it as an imaging technique, in synergy with other hyperspectral methods, or combining it with spot investigations. The most recent applications in the cultural Heritage field are taken into account, demonstrating how obtained 2D-XRF maps can be of great help in the diagnostic applied on Cultural Heritage materials. Moreover, a pioneering analysis protocol based on the Spectral Angle Mapper (SAM) algorithm is presented, unifying the MA-XRF standard approach with punctual XRF, exploiting information from the mapped area as a database to extend the comprehension to data outside the scanned region, and working independently from the acquisition set-up. Experimental application on some reference pigment layers and a painting by Giotto are presented as validation of the proposed method.

Lapis lazuli use stretches back more than 6500 years; ancient civilizations of Mesopotamia, Egypt, China, Greece, and Rome treasured and prized it. Afghanistan has been the oldest source for this stone, while Chile, Canada, Russia and a few other countries have been reported as sources for raw material in more recent times; the rarity of historical mines surely represents a positive aspect for the provenance clue of artefacts. Lapis lazuli is a rock consisting mainly of lazurite, to which it owes the blue colour, calcite and pyrite. Other constituents may be present, related to the different mines. In the present work, we apply the principles of Radio-luminescence (RL) exploiting as radiation source the X-ray tube of a portable commercial X-Ray Fluorescence spectrometer; in this way, X-Ray Fluorescence spectra (XRF) can be simultaneously acquired to have a larger set of data. To highlight the instrumental experimental differences, we refer to the portable set up as X-Ray Luminescence (XRL), as suggested by recent literature. We thus looked for the possibility of applying a wieldy, low cost and non-destructive method that could fit also to precious objects, based on the join use of XRF and XRL. We performed analyses on raw lapis lazuli stones from five different provenances, both historical and modern, and on four sets of unknown origin carved polished stones, to test our methods on real artefacts. We focalised on a limited number of samples to concentrate on the statistical treatment of spectra obtained, so to get a synergic response of the two applied techniques. We were able to obtain a clear distinction for the different classified provenances and could speculate those of unknown samples.

The process of degradation of archaeological glass subjected to centuries of burial can be of great relevance: typical consequence of degradation in the original vitreous material is rainbow-like iridescence due to chemical alteration of surface layers, salts formation and ion migration. The research presented in this paper is focused on the study of a collection of Roman glass (I - II century A.D.) held by the Museo Civico Etnografico Archeologico Fanchini of Oleggio, Italy. Chemical characterization (namely flux, chromophores and opacifiers determination) has been performed by a combination of X-Ray Fluorescence (XRF) and Fibre Optics Reflectance Spectroscopy (FORS) in the UV–Vis-NIR region. Conservation conditions have been studied and degraded areas have been mapped through Infrared thermography (IRT). IRT is a non-invasive method typically used to measure the apparent temperature of objects and represent it as pseudo-colour images. In the present work, we demonstrate the feasibility of IRT for identifying and mapping glass substrate defects due to ageing of glass, assuming that they may be considered as thermal anomalies. Thermogram sequences have been processed by high order statistical analysis, which is particularly suitable since it is based on automated processes where the output is a single representative image. The use of a thermal camera allows furthermore to perform remote analysis in areas hardly reachable in a fast and effective way.

The use of non-invasive analytical techniques on cultural heritage objects usually faces the insurmountable limit of dealing with artworks subjected to more restorations. For painted surfaces, imaging techniques, such as infrared photography (NIR) and ultraviolet-induced visible fluorescence (UVIVF), allow to distinguish areas with different kind and period of interventions. This paper presents the application of such techniques on two wooden coffins of the 21st Dynasty with a complex restoration history, the analytical inspections deal with the issues occurring in the reconstruction of a fluorescence map that is influenced by on both the use of non-original pigments and the presence of protective varnishes. In uncontrolled laboratory conditions, the possibility to associate quantitatively and univocally the luminance recorded by the camera with a certain level of fluorescence can be very difficult. An algorithm has been developed to obtain a map with an evident relationship between fluorescence and diagnostic information. First, the pixels of the fluorescent areas presenting different reflectance in the visible image have been used to equalize the visible image. Then, the ratio of the UVIVF image to the equalized image has been calculated, highlighting the low and non-fluorescent areas. After the thresholding and the segmentation of the UVIVF image, the masks obtained have been overlaid on the NIR images to merge and to map the areas with supposed similar restoration materials. The results illustrated in this work are followed by a punctual spectroscopic campaign, where the information on the imaging analysis is linked to and completed by the study of the chemical compounds in the coffins.

The process of degradation in artefacts subjected to centuries of burial can be of great relevance above all in archaeological glass. Infrared thermography is a non-destructive method allowing to map the defects of the glass substrate, both produced during its manufacturing (e.g., bubbles and inclusions) and due to ageing. This research is focused on the use of different flash thermography methods for the mapping of superficial flakes on Roman glasses dating back to the I and II century A.D. The effectiveness of active thermography methods is evaluated to map degraded portions of archaeological glass considering their semitransparency and specific optical absorption.